Abstract:
There is provided a semiconductor memory device, including: a plurality of bank groups each comprising a plurality of banks; a plurality of data pads grouped by a predetermined number for receiving data for the bank groups, wherein the data pads are divided into a plurality of first pad groups receiving data and a plurality of second pad groups selectively receiving data according to a data input/output option value; a first driving unit configured to drive data input via the first pad group to transfer the data input via the first pad group to the bank group corresponding to the first pad group; a second driving unit configured to drive data input via the second pad group to transfer the data input via the second pad group to the bank group corresponding to the second pad group; and a third driving unit configured to drive data input via the first pad group to transfer the data input via the first pad group to the bank group corresponding to the second pad group in response to the data input/output option value.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority of Korean patent application number 10-2008-0040930, filed on Apr. 30, 2008, which is incorporated by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     The subject matter relates to a semiconductor design technology, and in particular, to a method for driving a received data in a semiconductor memory device. More particularly, this application relates to a method for driving a received data at a variable data input/output bandwidth in a semiconductor memory device. 
     Generally, in a semiconductor memory device such as a dynamic random access memory (DRAM), a data input/output bandwidth represents the amount of data that can be simultaneously read or written by one addressing. The data input/output bandwidth makes it possible to perform more efficient operations by controlling the amount of data input/output according to the use purposes of the DRAM. For example, a DRAM used as a main memory might have an X8 data input/output bandwidth, whereas a DRAM used in a graphic card might have an X32 data input/output bandwidth. 
     Moreover, the data input/output bandwidth corresponds to the number of data input/output pads for the DRAM. For examples the DRAM for the main memory having the X8 data input/output bandwidth has eight data input/output pads, whereas the DRAM for the graphic card having the X32 data input/output bandwidth has thirty-two data input/output pads. 
     In the case of the DRAM used as the main memory, the data input/output bandwidth may be determined according to whether the DRAM is used in a personal computer (PC) which processes a relatively small amount of data or a server which processes a relatively large amount of data. In one example, a DRAM used in a notebook computer has the X4 data input/output bandwidth, a DRAM used in a desktop computer has the X8 data input/output bandwidth, and a DRAM used in a server has an X16 data input/output bandwidth. 
     In this way, as the DRAM is used as the main memory, since DRAMs having the same purpose also have a variable data input/output bandwidth, the DRAM used in the main memory is designed to selectively use the X4 data input/output bandwidth, the X8 data input/output bandwidth, and the X16 data input/output bandwidth. 
     That is, a DRAM is designed which uses the X16 data input/output bandwidth having the sixteen data input/output pads, and this DRAM using the X16 data input/output bandwidth can also be controlled to use only eight or four data input/output pads among the sixteen data input/output pads according to a user&#39;s selection, i.e., data input/output option, thereby enabling the DRAM with the X16 data input/output bandwidth to use the X4 data input/output bandwidth and the X8 data input/output bandwidth. 
     The DRAM used as the main memory can easily change the data input/output bandwidth according to the user&#39;s selection, as described above, because the DRAM used as the main memory has the following structure. 
       FIG. 1  is a block diagram showing a conventional DRAM structure for a main memory. 
     Referring to  FIG. 1 , a conventional DRAM for a main memory includes a plurality of banks BANK 0  through BANK 3 , global input/output line GI 0  (with sixteen lines) connected to the banks BANK 0 , BANK 1 , BANK 2  and BANK 3  to input and output data, and sixteen data input/output pads DQ 0  through DQ 15  corresponding to the sixteen lines in global input/output line GI 0 . 
     Since the conventional DRAM for the main memory has a structure that all the banks BANK 0  through BANK 3  are connected to all the data input/output pads DQ 0  through DQ 15 , all the sixteen data input/output pads DQ 0  through DQ 15  are used in the X16 data input/output bandwidth, only the eight data input/output pads DQ 0  through DQ 7  are used in the X8 data input/output bandwidth, and only the four data input/output pads DQ 0  through DQ 3  are used in the X4 data input/output bandwidth. Although the number of data input/output pads used in such a scheme is changed, it is not difficult to input external data to the banks BANK 0  through BANK 3  via the global input/output line GIO or to output data stored in the banks BANK 0  through BANK 3 . 
     In this way, the DRAM for the main memory can change the data input/output bandwidth according to a user&#39;s selection, whereas a DRAM for a graphics device uses a fixed X32 data input/output bandwidth. This is because the DRAM for the graphics device requires inputting/outputting data at far faster speed than the DRAM for the main memory so that it must have the following structure. 
       FIG. 2  is a block diagram illustrating a conventional DRAM structure for a graphics device. 
     Referring to  FIG. 2 , a conventional DRAM for a graphics device includes a plurality of bank groups  200 A through  200 D each including a plurality of banks BANK 0  through BANK 15 , a plurality of data input/output pads DQ 0  through DQ 31  in four groups of eight for respectively receiving data by the bank groups  200 A through  200 D, and four global input/output lines GI 0 _UL (with 8 lines), GI 0 _DL (with 8 lines), GI 0 _DR (with 8 lines) and GI 0 _UR (with 8 lines) respectively inputting/outputting data between the bank groups  200 A through  200 D and four data input/output pad groups  260 A through  260 D. 
     As shown in  FIG. 2 , the data input/output pads DQ 0  through DQ 31  are divided into the data input/output pad group  260 A corresponding to the zeroth bank group  200 A, the data input/output pad group  260 B corresponding to the first bank group  200 B, the data input/output pad group  260 C corresponding to the second bank group  200 C, and the data input/output pad group  260 D corresponding to the third bank group  200 D. 
     The four global input/output lines GI 0 _UL, GI 0 _DL, GI 0 _UR, and GI 0 _DR are divided into the eight lines of zeroth global input/output line GI 0 _UL for inputting/outputting data of the zeroth bank group  200 A, the eight lines of first global input/output line GI 0 _DL for inputting/outputting data of the first bank group  200 B, the eight lines of second global input/output line GI 0 _DR for inputting/outputting data of the second bank group  200 C, and the eight lines of third global input/output line GI 0 _UR for inputting/outputting data of the third bank group  200 D. 
     From the structure of the DRAM for the graphics device described above, it can be seen that none of the bank groups  200 A,  200 B,  200 C and  200 D is connected to all of the data input/output pads DQ 0  through DQ 31 . That is, the zeroth bank group  200 A can input/output data through only the data input/output pad group  260 A including the zeroth to seventh data input/output pads DQ 0  through DQ 7 . The first bank group  200 B can input/output data through only the data input/output pad group  260 B including the eighth to fifteenth data input/output pads DQ 8  through DQ 15 . The second bank group  200 C can input/output data through only the data input/output pad group  260 C including the sixteenth to twenty-third data input/output pads DQ 16  through DQ 23 . The third bank group  200 D can input/output data through only the data input/output pad group  260 D including the twenty-fourth to thirty-first data input/output pads DQ 24  through DQ 31 . 
     Accordingly, in a state where the data input/output bandwidth is changed into the X16 data input/output bandwidth, the second and third bank groups  200 C and  200 D cannot input/output data, as only the sixteen data input/output pads DQ 0  through DQ 15  are used. 
     To provide access to each of the bank groups, even in a case where the number of the data input/output pads for inputting/outputting data is reduced by the change of the data input/output bandwidth, the structure of the DRAM for the graphics device capable of inputting/outputting with all internal banks has been proposed as follows. 
       FIG. 3  is a block diagram showing a structure of a conventional DRAM for a graphics device, capable of easily changing a data input/output bandwidth. 
     Referring to  FIG. 3 , a conventional DRAM for a graphics device capable of changing a data input/output bandwidth includes a plurality of bank groups  300 A,  300 B,  300 C and  300 D each including a plurality of banks BANK 0  through BANK 15 , a plurality of data input/output pads DQ 0  through DQ 31  grouped by a predetermined number for receiving data by each of the bank groups  300 A through  300 D, first driving units  320 A and  320 C driving data D 0  through D 7  and D 16  through D 23  input through first pad groups  360 A and  360 C to transfer the data to the first and third bank groups  300 A and  300 C corresponding to the first pad groups  360 A and  360 C, second driving units  320 B and  320 D driving data D 8  through D 15  and D 24  through D 31  input through second pad groups  360 B and  360 D to transfer the data to the second and fourth bank groups  300 B and  300 D corresponding to the second pad groups  360 B and  360 D, and data division transferring units  340 A and  340 B transferring data D 0  through D 7  and D 16  through D 23  input through the first pad groups  360 A and  360 C to the first and third bank groups  300 A and  300 C corresponding to the first pad groups  360 A and  360 C and the second and fourth bank groups  300 B and  300 D corresponding to the second pad groups  360 B and  360 D. 
     Moreover, the conventional DRAM for the graphics device further includes first data transferring units  380 A and  380 C transferring any one of the output data D 0  through D 7  and D 16  through D 23  of the first driving units  320 A and  320 C and the output data D 0 , D 1 , D 2 , D 3 , D 4 , D 5 , D 6 , D 7 , D 16 , D 17 , D 18 , D 19 , D 20 , D 21 , D 22  and D 23  of the data division transferring units  340 A and  340 B to the first and third bank groups  300 A and  300 C corresponding to the first pad groups  360 A and  360 C in response to an address signal ADDRESS, and second data transferring units  380 B and  380 D transferring any one of the output data D 8 , D 9 , D 10 , D 11 , D 12 , D 13 , D 14 , D 15 , D 24 , D 25 , D 26 , D 27 , D 28 , D 29 , D 30  and D 31  of the second driving units  320 B and  320 D and the output data D 8 , D 9 , D 10 , D 11 , D 12 , D 13 , D 14 , D 15 , D 24 , D 25 , D 26 , D 27 , D 28 , D 29 , D 30  and D 31  of the data division transferring units  340 A and  340 B to the second and fourth bank groups  300 B and  300 D corresponding to the second pad groups  360 B and  360 D in response to the address signal ADDRESS. 
     At this point, the data input/output pads DQ 0 , DQ 1 , DQ 2 , DQ 3 , DQ 4 , DQ 5 , DQ 6 , DQ 7 , DQ 8 , DQ 9 , DQ 10 , DQ 11 , DQ 12 , DQ 13 , DQ 14 , DQ 15 , DQ 16 , DQ 17 , DQ 18 , DQ 19 , DQ 20 , DQ 21 , DQ 22 , DQ 23 , DQ 24 , DQ 25 , DQ 26 , DQ 27 , DQ 28 , DQ 29 , DQ 30  and DQ 31  are divided into the pad group  360 A corresponding to the zeroth bank group  300 A, the pad group  360 B corresponding to the first bank group  300 B, the pad group  360 C corresponding to the second bank group  300 C, and the pad group  360 D corresponding to the third bank group  300 D. The pad groups  360 A,  360 B,  360 C and  360 D are divided into the first pad groups  360 A and  360 C, which receive external data regardless of the data input/output bandwidth, and the second pad groups  360 B and  360 D, which selectively receive data according to the data input/output bandwidth of a semiconductor device. 
     According to the above-described configuration, in the conventional DRAM for the graphics device capable of changing a data input/output bandwidth, in the operation of the X16 data input/output bandwidth, it can be seen that data are input through the zeroth to seventh data input/output pads DQ 0 , DQ 1 , DQ 2 , DQ 3 , DQ 4 , DQ 5 , DQ 6  and DQ 7  and the sixteenth to twenty-third data input/output pads DQ 16 , DQ 17 , DQ 18 , DQ 19 , DQ 20 , DQ 21 , DQ 22  and DQ 23  included in the first pad groups  360 A and  360 C whereas data are not input through the eighth to fifteenth data input/output pads DQ 8 , DQ 9 , DQ 10 , DQ 11 , DQ 12 , DQ 13 , DQ 14 , DQ 15  and the twenty-fourth to thirty-first data input/output pads DQ 24 , DQ 25 , DQ 26 , DQ 27 , DQ 28 , DQ 29 , DQ 30  and DQ 31  included in the second pad groups  360 B and  360 D. 
     Alternatively, in the operation of the X32 data input/output bandwidth, it can be seen that data are input to all the data input/output pads DQ 0 , DQ 1 , DQ 2 , DQ 3 , DQ 4 , DQ 5 , DQ 6 , DQ 7 , DQ 8 , DQ 9 , DQ 10 , DQ 11 , DQ 12 , DQ 13 , DQ 14 , DQ 15 , DQ 16 , DQ 17 , DQ 18 , DQ 19 , DQ 20 , DQ 21 , DQ 22 , DQ 23 , DQ 24 , DQ 25 , DQ 26 , DQ 27 , DQ 28 , DQ 29 , DQ 30  and DQ 31  included in the first pad groups  360 A and  360 C and the second pad groups  360 B and  360 D. 
     Accordingly, it can be seen that the first driving units  320 A and  320 C are turned on and drive data input through the first pad groups  360 A and  360 C, in the operation of the X16 data input/output bandwidth and the operation of the X32 data input/output bandwidth. 
     On the other hand, it can be seen that the second driving units  320 B and  320 D are turned off not to perform any operation because data are not input through the second pad groups  360 B and  360 D in the operation of the X16 data input/output bandwidth, whereas they are turned on and drive data input trough the second pad groups  360 B and  360 D because data are input through the second pad groups  360 B and  360 D in the operation of the X32 data input/output bandwidth. 
     Furthermore, the data division transferring units  340 A and  340 B simply transfer the data D 0 , D 1 , D 2 , D 3 , D 4 , D 5 , D 6 , D 7 , D 16 , D 17 , D 18 , D 19 , D 20 , D 21 , D 22  and D 23  input through the first pad groups  360 A and  360 C to the first and third bank groups  300 A and  300 C corresponding to the first pad groups  360 A and  360 C and the second and fourth bank groups  300 B and  300 D corresponding to the second pad groups  360 B and  360 D. Such a configuration will be described in more detail below. 
       FIG. 4  is a circuit diagram illustrating a detailed structure of a conventional DRAM for a graphic capable of easily changing a data input/output bandwidth illustrated in  FIG. 3 . 
       FIG. 4  illustrates connection relationships between the zeroth data input/output pad DQ 0  included in the first pad groups  360 A and  360 C, the eighth data input/output pad DQ 8  included in the second pad groups  360 B and  360 D, a zeroth driver DRV 0  included in the first driving units  320 A and  320 C, an eighth driver DRV 8  included in the second driving units  320 B and  320 D, a zeroth path PTH 0  included in the data division transferring units  340 A and  340 B, a zeroth multiplexer MUX 0  included in the first data transferring units  380 A and  380 C, an eighth multiplexer MUX 8  included in the second data transferring units  380 B and  380 D, the zeroth bank group  300 A, and the first bank group  300 B, among the elements of the conventional DRAM for the graphics device capable of changing the data input/output bandwidth illustrated in  FIG. 3 . 
     In  FIG. 4 , for the convenience of the description, it is omitted to describe to connection relationships of the sixteenth driver DRV 16 , the sixteenth input/output pad DQ 16  and the sixteenth and twenty fourth multiplexers MUX 16  and MUX 24  shown in  FIG. 3 , since the sixteenth driver DRV 16 , the sixteenth input/output pad DQ 16  and the sixteenth and twenty fourth multiplexers MUX 16  and MUX 24  shown in  FIG. 3  are corresponding to the zeroth driver DRV 0 , the zeroth input/output pad DQ 0  and the zeroth and eighth multiplexers MUX 0  and MUX 8  shown in  FIG. 3 . 
     Referring to  FIG. 4 , among the elements of the conventional DRAM for the graphics device capable of changing the data input/output bandwidth illustrated in  FIG. 3 , the data division transferring units  340 A and  340 B simply receive the output data of the zeroth driver DRV 0  included in the first driving units  320 A and  320 C and only transfer the zeroth multiplexer MUX 0  included in the first data transferring units  380 A and  380 C and the eighth multiplexer MUX 8  included in the second data transferring units  380 B and  380 D. 
     That is, when data are output from the zeroth driver DRV 0  included in the first driving units  320 A and  320 C, the data division transferring units  340 A and  340 B unconditionally transfer the data to the zeroth multiplexer MUX 0  included in the first data transferring units  380 A and  380 C and the eighth multiplexer MUX 8  included in the second data transferring units  380 B and  380 D, and thus the data division transferring units  340 A and  340 B intend to transfer the output data of the zeroth driver DRV 0  included in the first driving units  320 A and  320 C to the zeroth and first bank groups  300 A and  300 B. 
     At this point, in the operation of the X16 data input/output bandwidth, the zeroth multiplexer MUX 0  included in the first data transferring units  380 A and  380 C and the eighth multiplexer MUX 8  respectively perform control for the output data of the zeroth path PTH 0  included in the data division transferring units  340 A and  340 B to be transferred to the zeroth bank group  300 A or the first bank group  300 B in response to the address signal ADDRESS. That is, the zeroth multiplexer MUX 0  included in the first data transferring units  380 A and  380 C and the eighth multiplexer MUX 8  respectively perform control for the output data of the zeroth driver DRV 0  included in the first driving units  320 A and  320 C applied to the zeroth path PTH 0  included in the data division transferring units  340 A and  340 B to be transferred the zeroth and first bank groups  300 A and  300 B. 
     Similarly, in the operation of the X32 data input/output bandwidth, the zeroth multiplexer MUX 0  included in the first data transferring units  380 A and  380 C and the eighth multiplexer MUX 8  respectively perform control for the output data of the zeroth driver DRV 0  included in the first driving units  320 A and  320 C to be transferred to the zeroth bank group  300 A and for the output data of the eighth driver DRV 8  included in the driving units  320 B and  320 D to be transferred to the first bank group  300 B in response to the address signal ADDRESS. 
     Additionally, the address signal ADDRESS, which determines whether the output data of the zeroth driver DRV 0  is transferred to the zeroth bank group  300 A or the first bank group  300 B, is applied to an address input pad (not shown) simultaneously with the application of the data D 0  of the zeroth data input/output pad DQ 0 . 
     Although the data division transferring units  340 A and  340 B operate with the above-described configuration, when the data input/output bandwidth is changed in the DRAM for the graphics device, data input through a predetermined data input/output pad may instead be driven to be transferred to all banks of the semiconductor memory device. 
     By the way, as illustrated in  FIGS. 3 and 4 , it can be seen that the data division transferring units  340 A and  340 B are disposed relatively near the first driving units  320 A and  320 C and the first data transferring units  380 A and  380 C, but is disposed relatively far from the second driving units  320 B and  320 D and the second data transferring units  380 B and  380 D. 
     That is, the first driving units  320 A and  320 C should transfer data input through the first pad groups  360 A and  360 C to the relatively near first data transferring units  380 A and  380 C, and should also transfer data input through the first pad groups  360 A and  360 C to the relatively far second data transferring units  380 B and  380 D. Accordingly, the driving power of the first driving units  320 A and  320 C is relatively strongly designed for the output data thereof to be stably transferred to the relatively far second data transferring units  380 B and  380 D. 
     On the other hand, since the second driving units  320 B and  320 D transfer data input through the second pad groups  360 B and  360 D to the relatively near second data transferring units  380 B and  380 D, the second driving units  320 B and  320 D are designed to have a relatively weak driving power. 
     In this way, in a case where the driving power of the first driving units  320 A and  320 C is relatively strongly designed, the driving power of the first driving units  320 A and  320 C can stably transfer the output data thereof to a far distance, but also consume a large amount of current in proportion to the transferring distance of the output data. 
     Particularly, in a case where the output data of the first driving units  320 A and  320 C should stably be transferred to the relatively far first bank group  300 B as well as the relatively near zeroth bank group  300 A like the operation of the X16 data input/output bandwidth, since it is preferential that data should stably be transferred, the driving power of the first driving units  320 A and  320 C may strongly be designed. 
     However, in a case where the output data of the first driving units  320 A and  320 C are transferred to only the relatively near zeroth bank group  300 A and are not transferred to the relatively far first bank group  300 B like the operation of the X32 data input/output bandwidth, there is no need that the driving power of the first driving units  320 A and  320 C is strongly designed. 
     By the way, the first driving units  320 A and  320 C have a strong driving power irrespective of the operation of the X16 data input/output bandwidth and the operation of the X32 data input/output bandwidth. Consequently, a current is consumed unnecessarily. 
     SUMMARY OF THE INVENTION 
     Embodiments of the present invention are directed to providing a DRAM for a graphics device which maintains the driving power of data input from a data input/output pad at a minimum corresponding to the data input/output bandwidth, for transferring the data to internal banks. 
     In accordance with an aspect of the present invention, there is provided a semiconductor memory device, including: a plurality of bank groups each comprising a plurality of banks; a plurality of data pads grouped by a predetermined number for receiving data for the bank groups, wherein the data pads are divided into a plurality of first pad groups receiving data and a plurality of second pad groups selectively receiving data according to a data input/output option value; a first driving unit configured to drive data input via the first pad group to transfer the data input via the first pad group to the bank group corresponding to the first pad group; a second driving unit configured to drive data input via the second pad group to transfer the data input via the second pad group to the bank group corresponding to the second pad group; and a third driving unit configured to drive data input via the first pad group to transfer the data input via the first pad group to the bank group corresponding to the second pad group in response to the data input/output option value. 
     In accordance with another aspect of the present invention, there is provided a semiconductor memory device, including: a plurality of bank groups each comprising a plurality of banks; a plurality of data pads grouped by a predetermined number for receiving data for each of the bank groups, wherein the data pads are divided into a plurality of first pad groups receiving data and a plurality of second pad groups selectively receiving data according to a data input/output option value; a plurality of pipe latches grouped by a predetermined number for latching data input via each data input/output pad, wherein the pipe latches are divided into a first pipe latch group latching data input via the first pad group and a second pipe latch group selectively latching data input via the first pad group or the second pad group in response to the data input/output option value; a first driving unit configured to drive data latched by the first pipe latch group to transfer the data latched by the first pipe latch group to the bank group corresponding to the first pad group; a second driving unit configured to drive data latched by the second pipe latch group to transfer the data latched by the second pipe latch group to the bank group corresponding to the second pad group; and a data transferring unit configured to transfer data input via the first pad group or the second pad group to the second pipe latch group in response to the data input/output option value. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram showing a conventional DRAM structure for a main memory. 
         FIG. 2  is a block diagram showing a conventional DRAM structure for a graphic. 
         FIG. 3  is a block diagram showing a structure of a conventional DRAM for a graphics device capable of changing a data input/output bandwidth. 
         FIG. 4  is a circuit diagram showing a detailed structure of a conventional DRAM for a graphics device capable of changing a data input/output bandwidth illustrated in  FIG. 3 . 
         FIG. 5  is a block diagram illustrating the structure of a DRAM for a graphics device capable of changing a data input/output bandwidth in accordance with a first embodiment of the present invention. 
         FIG. 6  is a circuit diagram illustrating a detailed structure of a DRAM for a graphics device capable of easily changing a data input/output bandwidth in accordance with a first embodiment of the present invention. 
         FIG. 7  is a block diagram illustrating the structure of a DRAM for a graphics device capable of easily changing a data input/output bandwidth in accordance with a second embodiment of the present invention. 
         FIG. 8  is a circuit diagram illustrating a detailed structure of a DRAM for a graphics device capable of easily changing a data input/output bandwidth a second embodiment of the present invention illustrated in  FIG. 7 . 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. 
     First Embodiment 
       FIG. 5  is a block diagram illustrating the structure of a DRAM for a graphics device capable of easily changing a data input/output bandwidth in accordance with a first embodiment of the present invention. 
     Referring to  FIG. 5 , a DRAM for a graphics device capable of easily changing data input/output bandwidth in accordance with a first embodiment of the present invention includes a plurality of bank groups  500 A,  500 B,  500 C and  500 D each including a plurality of banks BANK 0 , BANK 1 , BANK 2 , BANK 3 , BANK 4 , BANK 5 , BANK 6 , BANK 7 , BANK 8 , BANK 9 , BANK 10 , BANK 11 , BANK 12 , BANK 13 , BANK 14  and BANK 15 , a plurality of data input/output pads DQ 0 , DQ 1 , DQ 2 , DQ 3 , DQ 4 , DQ 5 , DQ 6 , DQ 7 , DQ 8 , DQ 9 , DQ 10 , DQ 11 , DQ 12 , DQ 13 , DQ 14 , DQ 15 , DQ 16 , DQ 17 , DQ 18 , DQ 19 , DQ 20 , DQ 21 , DQ 22 , DQ 23 , DQ 24 , DQ 25 , DQ 26 , DQ 27 , DQ 28 , DQ 29 , DQ 30  and DQ 31  grouped by a predetermined number for receiving data into the bank groups  500 A,  500 B,  500 C and  500 D, first driving units  520 A and  520 C driving data D 0 , D 1 , D 2 , D 3 , D 4 , D 5 , D 6 , D 7 , D 16 , D 17 , D 18 , D 19 , D 20 , D 21 , D 22  and D 23  input through first pad groups  560 A and  560 C to transfer the data to the first and third bank groups  500 A and  500 C corresponding to the first pad groups  560 A and  560 C, second driving units  520 B and  520 D driving data D 8 , D 9 , D 10 , D 11 , D 12 , D 13 , D 14 , D 15 , D 24 , D 25 , D 26 , D 27 , D 28 , D 29 , D 30  and D 31  input through second pad groups  560 B and  560 D to transfer the data to the second and fourth bank groups  500 B and  500 D corresponding to the second pad groups  560 B and  560 D, and third driving units  540 A and  540 B driving data D 0 , D 1 , D 2 , D 3 , D 4 , D 5 , D 6 , D 7 , D 16 , D 17 , D 18 , D 19 , D 20 , D 21 , D 22  and D 23  input through first pad groups  560 A and  560 C to transfer them to the second and fourth bank groups  500 B and  500 D corresponding to the second pad groups  560 B and  560 D according to a data input/output option value DATA_IO_OP. 
     Moreover, the DRAM for the graphics device in accordance with the first embodiment of the present invention further includes first data transferring units  580 A and  580 C transferring any one of the output data D 0 , D 1 , D 2 , D 3 , D 4 , D 5 , D 6 , D 7 , D 16 , D 17 , D 18 , D 19 , D 20 , D 21 , D 22  and D 23  of the first driving units  520 A and  520 C and the output data D 0 , D 1 , D 2 , D 3 , D 4 , D 5 , D 6 , D 7 , D 16 , D 17 , D 18 , D 19 , D 20 , D 21 , D 22  and D 23  of the third driving units  540 A and  540 B to the first and third bank groups  500 A and  500 C corresponding to the first pad groups  560 A and  560 C in response to an address signal ADDRESS, and second data transferring units  580 B and  580 D transferring any one of the output data D 8 , D 9 , D 10 , D 11 , D 12 , D 13 , D 14 , D 15 , D 24 , D 25 , D 26 , D 27 , D 28 , D 29 , D 30  and D 31  of the second driving units  520 B and  520 D and the output data D 8 , D 9 , D 10 , D 11 , D 12 , D 13 , D 14 , D 15 , D 24 , D 25 , D 26 , D 27 , D 28 , D 29 , D 30  and D 31  of the third driving units  540 A and  540 B to the second and fourth bank groups  500 B and  500 D corresponding to the second pad groups  560 B and  560 D in response to the address signal ADDRESS. 
     At this point, the data input/output pads DQ 0 , DQ 1 , DQ 2 , DQ 3 , DQ 4 , DQ 5 , DQ 6 , DQ 7 , DQ 8 , DQ 9 , DQ 10 , DQ 11 , DQ 12 , DQ 13 , DQ 14 , DQ 15 , DQ 16 , DQ 17 , DQ 18 , DQ 19 , DQ 20 , DQ 21 , DQ 22 , DQ 23 , DQ 24 , DQ 25 , DQ 26 , DQ 27 , DQ 28 , DQ 29 , DQ 30  and DQ 31  are divided into the pad group  560 A corresponding to the zeroth bank group  500 A, the pad group  560 B corresponding to the first bank group  500 B, the pad group  560 C corresponding to the second bank group  500 C, and the pad group  560 D corresponding to the third bank group  500 D. The pad groups  560 A,  560 B,  560 C and  560 D are divided into the first pad groups  560 A and  560 C receiving external data regardless of the data input/output bandwidth and the second pad groups  560 B and  560 D selectively receiving data according to the data input/output bandwidth. 
     According to the above-described configuration, in the DRAM for the graphics device in accordance with the first embodiment of the present invention, in the operation of the X16 data input/output bandwidth, it can be seen that data are input through the zeroth to seventh data input/output pads DQ 0 , DQ 1 , DQ 2 , DQ 3 , DQ 4 , DQ 5 , DQ 6  and DQ 7  and the sixteenth to twenty-third data input/output pads DQ 16 , DQ 17 , DQ 18 , DQ 19 , DQ 20 , DQ 21 , DQ 22  and DQ 23  included in the first pad groups  560 A and  560 C, whereas data are not input through the eighth to fifteenth data input/output pads DQ 8 , DQ 9 , DQ 10 , DQ 11 , DQ 12 , DQ 13 , DQ 14 , DQ 15  and the twenty-fourth to thirty-first data input/output pads DQ 24 , DQ 25 , DQ 26 , DQ 27 , DQ 28 , DQ 29 , DQ 30  and DQ 31  included in the second pad groups  560 B and  560 D. 
     Alternatively, in the operation of the X32 data input/output bandwidth, it can be seen that data are input to all the data input/output pads DQ 0 , DQ 1 , DQ 2 , DQ 3 , DQ 4 , DQ 5 , DQ 6 , DQ 7 , DQ 8 , DQ 9 , DQ 10 , DQ 11 , DQ 12 , DQ 13 , DQ 14 , DQ 15 , DQ 16 , DQ 17 , DQ 18 , DQ 19 , DQ 20 , DQ 21 , DQ 22 , DQ 23 , DQ 24 , DQ 25 , DQ 26 , DQ 27 , DQ 28 , DQ 29 , DQ 30  and DQ 31  included in the first pad groups  560 A and  560 C and the second pad groups  560 B and  560 D. 
     Accordingly, it can be seen that the first driving units  520 A and  520 C are turned on and drive data input through the first pad groups  560 A and  560 C, in the operation of the X16 data input/output bandwidth and the operation of the X32 data input/output bandwidth. 
     On the other hand, it can be seen that the second driving units  520 B and  520 D are turned off not to perform any operation because data are not input through the second pad groups  560 B and  560 D in the operation of the X16 data input/output bandwidth, whereas they are turned on and drive data input trough the second pad groups  560 B and  560 D because data are input through the second pad groups  560 B and  560 D in the operation of the X32 data input/output bandwidth. 
     Furthermore, it can be seen that the third driving units  540 A and  540 B are turned on and drive data input through the first pad groups  560 A and  560 C in a first selection mode of the data input/output option value DATA_IO_OP operating by the X16 data input/output bandwidth, and are turned off not to perform any operation in a second selection mode of the data input/output option value DATA_IO_OP operating by the X32 data input/output bandwidth. 
       FIG. 6  is a circuit diagram illustrating a detailed structure of a DRAM for a graphics device capable of easily changing a data input/output bandwidth in accordance with a first embodiment of the present invention. 
       FIG. 6  illustrates connection relationships between the zeroth data input/output pad DQ 0  included in the first pad groups  560 A and  560 C, the eighth data input/output pad DQ 8  included in the second pad groups  560 B and  560 D, a zeroth driver DRV 0  included in the first driving units  520 A and  520 C, an eighth driver DRV 8  included in the second driving units  520 B and  520 D, a zeroth pass driver PDV 0  included in the third driving units  540 A and  540 B, a zeroth multiplexer MUX 0  included in the first data transferring units  580 A and  580 C, an eighth multiplexer MUX 8  included in the second data transferring units  580 B and  580 D, the zeroth bank group  500 A, and the first bank group  500 B, among the elements of the DRAM for the graphics device capable of easily changing the data input/output bandwidth in accordance with the first embodiment of the present invention illustrated in  FIG. 5 . 
     In  FIG. 6 , for the convenience of the description, it is omitted to describe to connection relationships of the sixteenth and twenty fourth input/output pads DQ 16  and DQ 24  shown in  FIG. 5 , since the sixteenth and twenty fourth input/output pads DQ 16  and DQ 24  shown in  FIG. 5  are corresponding to the zeroth and eighth input/output pads DQ 0  and DQ 8  shown in  FIG. 5 . 
     Referring to  FIG. 6 , it can be seen that the zeroth driver DRV 0  included in the first driving units  520 A and  520 C is turned on in both the operation of the X16 data input/output bandwidth and the operation of the X32 data input/output bandwidth so that data are input through the zeroth data input/output pad DQ 0  included in the first pad groups  560 A and  560 B, thereby driving data input through the zeroth data input/output pad DQ 0  included in the first pad groups  560 A and  560 B. 
     Furthermore, it can be seen that the eighth driver DRV 8  included in the second driving units  520 B and  520 D is turned off not to perform any operation because data are not input through the eighth data input/output pad DQ 8  included in the second pad groups  560 B and  560 D in the operation of the X16 data input/output bandwidth, whereas it is turned on and drives data input trough the eighth data input/output pad DQ 8  included in the second pad groups  560 B and  560 D because data are input through the eighth data input/output pad DQ 8  included in the second pad groups  560 B and  560 D in the operation of the X32 data input/output bandwidth. 
     It can be seen that the zeroth pass driver PDV 0  included in the third driving units  540 A and  540 B is turned on and drives data input through the zeroth data input/output pad DQ 0  included in the first pad groups  560 A and  560 B in the first selection mode of the data input/output option value DATA_IO_OP operating by the X16 data input/output bandwidth, whereas it is turned off not to perform any operation according to the data input/output option value DATA_IO_OP in the second selection mode of the data input/output option value DATA_IO_OP operating by the X32 data input/output bandwidth. 
     That is, the first driving units  520 A and  520 C and the second driving units  520 B and  520 D respectively operates to drive data input through the first pad groups  560 A and  560 C and data input through the second pad groups  560 B and  560 D in the operation of the X16 data input/output bandwidth, and the first driving units  520 A and  520 C and the third driving units  540 A and  540 B respectively operates to drive only data input through the first pad groups  560 A and  560 C in the operation of the X32 data input/output bandwidth. 
     At this point, since the first driving units  520 A and  520 C and the second driving units  520 B and  520 D are designed to have a relatively weak driving power and the third driving units  540 A and  540 B are designed to have a relatively strong driving power, a level of a used driving power is changed according to whether an operation is the operation of the X32 data input/output bandwidth or the operation of the X16 data input/output bandwidth. 
     That is, in the first selection mode of the data input/output option value DATA_IO_OP operating by the X16 data input/output bandwidth, since the third driving units  540 A and  540 B having a relatively strong driving power are used, a relatively high current is consumed. In the second selection mode of the data input/output option value DATA_IO_OP operating by the X32 data input/output bandwidth, since the first driving units  520 A and  520 C and the second driving units  520 B and  520 D having a relatively weak driving power are used, a relatively low current is consumed. Therefore, an amount of current consumed in the first to third driving units  520 A,  520 B,  520 C,  520 D,  540 A and  540 B is changed according to whether the data input/output option value DATA_IO_OP is the first selection mode or the second selection mode. 
     In a case where the first embodiment of the present invention is applied as described above, the DRAM for the graphics device capable of changing the data input/output bandwidth includes the data driving units which can drive data input through the data input/output pads by a driving power corresponding to the data input/output option value DATA_IO_OP to transfer the data to the internal banks, thereby driving the data input through the data input/output pads by consuming a minimum amount of current regardless of the change of the data input/output bandwidth. 
     Second Embodiment 
       FIG. 7  is a block diagram illustrating the structure of a DRAM for a graphics device capable of easily changing a data input/output bandwidth in accordance with a second embodiment of the present invention. 
     Referring to  FIG. 7 , a DRAM for a graphic capable of easily changing data input/output bandwidth in accordance with a second embodiment of the present invention includes a plurality of bank groups  700 A,  700 B,  700 C and  700 D each including a plurality of banks BANK 0 , BANK 1 , BANK 2 , BANK 3 , BANK 4 , BANK 5 , BANK 6 , BANK 7 , BANK 8 , BANK 9 , BANK 10  BANK 11 , BANK 12 , BANK 13 , BANK 14  and BANK 15 , a plurality of data input/output pads DQ 0 , DQ 1 , DQ 2 , DQ 3 , DQ 4 , DQ 5 , DQ 6 , DQ 7 , DQ 8 , DQ 9 , DQ 10 , DQ 11 , DQ 12 , DQ 13 , DQ 14 , DQ 15 , DQ 16 , DQ 17 , DQ 18 , DQ 19 , DQ 20 , DQ 21 , DQ 22 , DQ 23 , DQ 24 , DQ 25 , DQ 26 , DQ 27 , DQ 28 , DQ 29 , DQ 30  and DQ 31  grouped by a predetermined number for receiving data into the bank groups  700 A,  700 B,  700 C and  700 D, a plurality of pipe latches PL 0 , PL 1 , PL 2 , PL 3 , PL 4 , PL 5 , PL 6 , PL 7 , PL 8 , PL 9 , PL 10 , PL 11 , PL 12 , PL 13 , PL 14 , PL 15 , PL 16 , PL 17 , PL 18 , PL 19 , PL 20 , PL 21 , PL 22 , PL 23 , PL 24 , PL 25 , PL 26 , PL 27 , PL 28 , PL 29 , PL 30  and PL 31  grouped by a predetermined number for latching the data D 0 , D 1 , D 2 , D 3 , D 4 , D 5 , D 6 , D 7 , D 8 , D 9 , D 10 , D 11 , D 12 , D 13 , D 14 , D 15 , D 16 , D 17 , D 18 , D 19 , D 20 , D 21 , D 22 , D 23 , D 24 , D 25 , D 26 , D 27 , D 28 , D 29 , D 30  and D 31  input through each of the data input/output pads DQ 0 , DQ 1 , DQ 2 , DQ 3 , DQ 4 , DQ 5 , DQ 6 , DQ 7 , DQ 8 , DQ 9 , DQ 10 , DQ 11 , DQ 12 , DQ 13 , DQ 14 , DQ 15 , DQ 16 , DQ 17 , DQ 18 , DQ 19 , DQ 20 , DQ 21 , DQ 22 , DQ 23 , DQ 24 , DQ 25 , DQ 26 , DQ 27 , DQ 28 , DQ 29 , DQ 30  and DQ 31 , first driving units  720 A and  720 C driving the data D 0 , D 1 , D 2 , D 3 , D 4 , D 5 , D 6 , D 7 , D 16 , D 17 , D 18 , D 19 , D 20 , D 21 , D 22  and D 23  latched by first pipe latch groups  730 A and  730 C to transfer the data to the first and third bank groups  700 A and  700 C corresponding to the first pad groups  760 A and  760 C, second driving units  720 B and  720 D driving the data D 0 , D 1 , D 2 , D 3 , D 4 , D 5 , D 6 , D 7 , D 8 , D 9 , D 10 , D 11 , D 12 , D 13 , D 14 , D 15 , D 16 , D 17 , D 18 , D 19 , D 20 , D 21 , D 22 , D 23 , D 24 , D 25 , D 26 , D 27 , D 28 , D 29 , D 30  and D 31  latched by second pipe latch groups  730 B and  730 D to transfer the data to the second and fourth bank groups  700 B and  700 D corresponding to the second pad groups  760 B and  760 D, and data transferring units  770 A and  770 B the data D 0 , D 1 , D 2 , D 3 , D 4 , D 5 , D 6 , D 7 , D 16 , D 17 , D 18 , D 19 , D 20 , D 21 , D 22  and D 23  input through the first pad groups  760 A and  760 C or the data D 8 , D 9 , D 10 , D 11 , D 12 , D 13 , D 14 , D 15 , D 24 , D 25 , D 26 , D 27 , D 28 , D 29 , D 30  and D 31  input through the second pad groups  760 B and  760 D to transfer the data to the second pipe latch groups  730 B and  730 D according to the data input/output option value DATA_IO_OP. 
     At this point, the data input/output pads DQ 0 , DQ 1 , DQ 2 , DQ 3 , DQ 4 , DQ 5 , DQ 6 , DQ 7 , DQ 8 , DQ 9 , DQ 10 , DQ 11 , DQ 12 , DQ 13 , DQ 14 , DQ 15 , DQ 16 , DQ 17 , DQ 18 , DQ 19 , DQ 20 , DQ 21 , DQ 22 , DQ 23 , DQ 24 , DQ 25 , DQ 26 , DQ 27 , DQ 28 , DQ 29 , DQ 30  and DQ 31  are divided into the pad group  760 A corresponding to the zeroth bank group  700 A, the pad group  760 B corresponding to the first bank group  700 B, the pad group  760 C corresponding to the second bank group  700 C, and the pad group  760 D corresponding to the third bank group  700 D. The pad groups  760 A,  760 B,  760 C and  760 D are divided into the first pad groups  760 A and  760 C receiving external data regardless of the data input/output bandwidth and the second pad groups  760 B and  760 D selectively receiving data according to the data input/output bandwidth. 
     According to the above-described configuration, in the DRAM for the graphics device in accordance with the second embodiment of the present invention, in the operation of the X16 data input/output bandwidth, it can be seen that data are input through the zeroth to seventh data input/output pads DQ 0 , DQ 1 , DQ 2 , DQ 3 , DQ 4 , DQ 5 , DQ 6  and DQ 7  and the sixteenth to twenty-third data input/output pads DQ 16 , DQ 17 , DQ 18 , DQ 19 , DQ 20 , DQ 21 , DQ 22  and DQ 23  included in the first pad groups  760 A and  760 C whereas data are not input through the eighth to fifteenth data input/output pads DQ 8 , DQ 9 , DQ 10 , DQ 11 , DQ 12 , DQ 13 , DQ 14 , DQ 15  and the twenty-fourth to thirty-first data input/output pads DQ 24 , DQ 25 , DQ 26 , DQ 27 , DQ 28 , DQ 29 , DQ 30  and DQ 31  included in the second pad groups  760 B and  760 D. 
     Likewise, in the operation of the X32 data input/output bandwidth, it can be seen that data are input to all the data input/output pads DQ 0 , DQ 1 , DQ 2 , DQ 3 , DQ 4 , DQ 5 , DQ 6 , DQ 7 , DQ 8 , DQ 9 , DQ 10 , DQ 11 , DQ 12 , DQ 13 , DQ 14 , DQ 15 , DQ 16 , DQ 17 , DQ 18 , DQ 19 , DQ 20 , DQ 21 , DQ 22 , DQ 23 , DQ 24 , DQ 25 , DQ 26 , DQ 27 , DQ 28 , DQ 29 , DQ 30  and DQ 31  included in the first pad groups  760 A and  760 C and the second pad groups  760 B and  760 D. 
     In this state, the data D 0 , D 1 , D 2 , D 3 , D 4 , D 5 , D 6 , D 7 , D 16 , D 17 , D 18 , D 19 , D 20 , D 21 , D 22  and D 23  input through the zeroth to seventh data input/output pads DQ 0 , DQ 1 , DQ 2 , DQ 3 , DQ 4 , DQ 5 , DQ 6  and DQ 7  and the sixteenth to twenty-third data input/output pads DQ 16 , DQ 17 , DQ 18 , DQ 19 , DQ 20 , DQ 21 , DQ 22  and DQ 23  included in the first pad groups  760 A and  760 C are applied to the first input terminals of a plurality of multiplexers P_MUX_ 0 , P_MUX_ 1 , P_MUX_ 2 , P_MUX_ 3 , P_MUX_ 4 , P_MUX_ 5 , P_MUX_ 6 , P_MUX_ 7 , P_MUX_ 8 , P_MUX_ 9 , P_MUX_ 10 , P_MUX_ 11 , P_MUX_ 12 , P_MUX_ 13 , P_MUX_ 14  and P_MUX_ 15  included in the data transferring units  770 A and  770 B. The data D 8 , D 9 , D 10 , D 11 , D 12 , D 13 , D 14 , D 15 , D 24 , D 25 , D 26 , D 27 , D 28 , D 29 , D 30  and D 31  input through the eighth to fifteenth data input/output pads DQ 8 , DQ 9 , DQ 10 , DQ 11 , DQ 12 , DQ 13 , DQ 14 , DQ 15  and the twenty-fourth to thirty-first data input/output pads DQ 24 , DQ 25 , DQ 26 , DQ 27 , DQ 28 , DQ 29 , DQ 30  and DQ 31  included in the second pad groups  760 B and  760 D are applied to the second input terminals of a plurality of multiplexers P_MUX_ 0 , P_MUX_ 1 , P_MUX_ 2 , P_MUX_ 3 , P_MUX_ 4 , P_MUX_ 5 , P_MUX_ 6 , P_MUX_ 7 , P_MUX_ 8 , P_MUX_ 9 , P_MUX_ 10 , P_MUX_ 11 , P_MUX_ 12 , P_MUX_ 13 , P_MUX_ 14  and P_MUX_ 15  included in the data transferring units  770 A and  770 B. The applied data D 0 , D 1 , D 2 , D 3 , D 4 , D 5 , D 6 , D 7 , D 16 , D 17 , D 18 , D 19 , D 20 , D 21 , D 22  and D 23 , or the applied data D 8 , D 9 , D 10 , D 11 , D 12 , D 13 , D 14 , D 15 , D 24 , D 25 , D 26 , D 27 , D 28 , D 29 , D 30  and D 31  are selectively transferred to the second pipe latch groups  730 B and  730 D according to the data input/output option value DATA_IO_OP. 
     Accordingly, the data transferring units  770 A and  770 B transfer the data D 0 , D 1 , D 2 , D 3 , D 4 , D 5 , D 6 , D 7 , D 16 , D 17 , D 18 , D 19 , D 20 , D 21 , D 22  and D 23  of the first pad groups  760 A and  760 C applied to the first input terminals of the multiplexers to the second pipe latch groups  730 B and  730 D, in the first selection mode of the data input/output option value DATA_IO_OP operating by the X16 data input/output bandwidth. The data transferring units  770 A and  770 B transfer the data D 8 , D 9 , D 10 , D 11 , D 12 , D 13 , D 14 , D 15 , D 24 , D 25 , D 26 , D 27 , D 28 , D 29 , D 30  and D 31  of the second pad groups  760 B and  760 D applied to the second input terminals of the multiplexers to the second pipe latch groups  730 B and  730 D, in the second selection mode of the data input/output option value DATA_IO_OP operating by the X32 data input/output bandwidth. 
       FIG. 8  is a circuit diagram illustrating a detailed structure of a DRAM for a graphic capable of easily changing a data input/output bandwidth in accordance with the second embodiment of the present invention illustrated in  FIG. 7 . 
       FIG. 8  illustrates connection relationships between the zeroth data input/output pad DQ 0  included in the first pad groups  760 A and  760 C, a zeroth pipe latch PL 0  included in the first pipe latch groups  730 A and  730 C, the eighth data input/output pad DQ 8  included in the second pad groups  760 B and  760 D, an eighth pipe latch PL 8  included in the second pipe latch groups  730 B and  730 D, and the zeroth multiplexer P_MUX_ 0  included in the data transferring units  770 A and  770 B. 
     In  FIG. 8 , for the convenience of the description, it will be omitted to describe to connection relationships of the sixteenth and twenty fourth pipe latches PL 16  and PL 24 , the sixteenth input/output pad DQ 16  and the sixteenth and twenty fourth multiplexers P_MUX 16  and P_MUX 24  shown in  FIG. 7 , since the sixteenth and twenty fourth pipe latches PL 16  and PL 24 , the sixteenth input/output pad DQ 16  and the sixteenth and twenty fourth multiplexers P_MUX 16  and P_MUX 24  shown in  FIG. 7  are corresponding to the zeroth and eight pipe latches PL 0  and PL 8 , the zeroth input/output pad DQ 0  and the zeroth and eighth multiplexers P_MUX 0  and P_MUX 8  shown in  FIG. 7 . 
     Referring to  FIG. 8 , the zeroth data input/output pad DQ 0  is directly connected to the input terminal of the zeroth pipe latch PL 0  and is also connected to the first input terminal of the zeroth multiplexer P_MUX_ 0 , the eighth data input/output pad DQ 8  is connected to the second input terminal of the zeroth multiplexer P_MUX_ 0 , and the output terminal of the zeroth multiplexer P_MUX_ 0  is connected to the input terminal of the eighth pipe latch PL 8 . 
     Herein, each of the zeroth pipe latch PL 0  and the eighth pipe latch PL 8  includes a plurality of pipelines P_LINE_ 1 , P_LINE_ 2  and P_LINE_ 3 . The pipelines P_LINE_ 1 , P_LINE_ 2  and P_LINE_ 3  included in the zeroth pipe latch PL 0  respectively receive the data of an input terminal thereof in response to a plurality of pipeline input signals PIPE_IN_ 1 , PIPE_IN_ 2  and PIPE_IN_ 3 , and respectively output the received data to the zeroth driver DRV 0  included in the first driving units  720 A and  720 C in response to a plurality of first pipeline output signals PIPE_OUT_UP_ 1 , PIPE_OUT_UP_ 2  and PIPE_OUT_UP_ 3 . 
     The pipelines P_LINE_ 1 , P_LINE_ 2  and P_LINE_ 3  included in the eighth pipe latch PL 8  respectively receive the data of an input terminal thereof in response to the pipeline input signals PIPE_IN_ 1 , PIPE_IN_ 2  and PIPE_IN_ 3 , and respectively output the received data to the eighth driver DRV 8  included in the second driving units  720 B and  720 D in response to a plurality of second pipeline output signals PIPE_OUT_DN_ 1 , PIPE_OUT_DN_ 2  and PIPE_OUT_DN_ 3 . 
     The zeroth multiplexer P_MUX_ 0  transfers one of the data D 0  of the zeroth data input/output pad DQ 0  applied through the first input terminal thereof and the data D 8  of the eighth data input/output pad DQ 8  applied through the second input terminal thereof to the input terminal of the eighth pipe latch PL 8  in response to the data input/output option value DATA_IO_OP. 
     The DRAM in accordance with the second embodiment will be described below with reference to such a configuration. 
     First, the data D 0  input to the zeroth data input/output pad DQ 0  included in the first pad groups  760 A and  760 C is transferred to the zeroth pipe latch PL 0  included in the first pipe latch groups  730 A and  730 C and are simultaneously transferred to the eighth pipe latch PL 8  included in the second pipe latch groups  730 B and  730 D, in the first selection mode of the data input/output option value DATA_IO_OP operating by the X16 data input/output bandwidth. 
     That is, the zeroth multiplexer P_MUX_ 0  transfers the data D 0  of the zeroth data input/output pad DQ 0  applied through the first input terminal thereof to the eighth pipe latch PL 8  in the second selection mode of the data input/output option value DATA_IO_OP operating by the X32 data input/output bandwidth. 
     In this way, the data D 0  of the zeroth data input/output pad DQ 0  transferred to each of the zeroth pipe latch PL 0  and the eighth pipe latch PL 8  is latched by any one of the pipelines P_LINE_ 1 , P_LINE_ 2  and P_LINE_ 3  according to the pipeline input signals PIPE_IN_ 1 , PIPE_IN_ 2  and PIPE_IN_ 3 . 
     Additionally, since an 8-bit prefetch operation should be performed when the data D 0  of the zeroth data input/output pad DQ 0  is 8 bits, a capacity of the pipelines P_LINE_ 1 , P_LINE_ 2  and P_LINE_ 3  included in each of the zeroth pipe latch PL 0  and the eighth pipe latch PL 8  also is 8 bits. Since an 4-bit prefetch operation should be performed when the data D 0  of the zeroth data input/output pad DQ 0  is 4 bits, a capacity of the pipelines P_LINE_ 1 , P_LINE_ 2  and P_LINE_ 3  included in each of the zeroth pipe latch PL 0  and the eighth pipe latch PL 8  also is 4 bits. 
     In this way, the zeroth pipe latch PL 0  and the eighth pipe latch PL 8  latch the data D 0  of the zeroth data input/output pad DQ 0  at the same time. However, in a case where the first pipeline output signals PIPE_OUT_UP_ 1 , PIPE_OUT_UP_ 2  and PIPE_OUT_UP_ 3  are toggled, the data latched by the zeroth pipe latch PL 0  is output to the zeroth driver DRV 0  included in the first driving units  720 A and  720 B and is transferred to the zeroth bank group  700 A. In a case where the second pipeline output signals PIPE_OUT_DN_ 1 , PIPE_OUT_DN_ 2  and PIPE_OUT_DN_ 3  are toggled, the data latched by the eighth pipe latch PL 8  is output to the eighth driver DRV 8  included in the second driving units  720 B and  720 D and is transferred to the third bank group  700 C. 
     That is, in a case where a predetermined place in which the data D 0  of the zeroth data input/output pad DQ 0  should be stored is included in the zeroth bank group  700 A, control is performed for the first pipeline output signals PIPE_OUT_UP_ 1 , PIPE_OUT_UP_ 2  and PIPE_OUT_UP_ 3  to be toggled. In a case where the predetermined place in which the data D 0  of the zeroth data input/output pad DQ 0  should be stored is included in the third bank group  700 C, control is performed for the second pipeline output signals PIPE_OUT_DN_ 1 , PIPE_OUT_DN_ 2  and PIPE_OUT_DN_ 3  to be toggled. 
     Additionally, the predetermined place in which the data D 0  of the zeroth data input/output pad DQ 0  should be stored can be seen through the address signal ADDRESS applied to an address input pad (not shown) simultaneously with the application of the data D 0  of the zeroth data input/output pad DQ 0 . 
     Accordingly, a circuit (not shown) for controlling the toggling of the first pipeline output signals PIPE_OUT_UP_ 1 , PIPE_OUT_UP_ 2  and PIPE_OUT_UP_ 3  and the second pipeline output signals PIPE_OUT_DN_ 1 , PIPE_OUT_DN_ 2  and PIPE_OUT_DN_ 3  operates in response to the address signal ADDRESS applied to the address input pad. 
     Furthermore, the data D 0  input to the zeroth data input/output pad DQ 0  included in the first pad groups  760 A and  760 C is transferred to the zeroth pipe latch PL 0  included in the first pipe latch groups  730 A and  730 C, and the data D 8  input to the eighth data input/output pad DQ 8  included in the second pad groups  760 B and  760 D is transferred to the eighth pipe latch PL 8  included in the second pipe latch groups  730 B and  730 D, in the second selection mode of the data input/output option value DATA_IO_OP operating by the X32 data input/output bandwidth. 
     That is, the zeroth multiplexer P_MUX_ 0  transfers the data D 8  of the eighth data input/output pad DQ 8  applied through the second input terminal thereof to the eighth pipe latch PL 8 , in the second selection mode of the data input/output option value DATA_IO_OP operating by the X32 data input/output bandwidth. 
     In this way, the data D 0  of the zeroth data input/output pad DQ 0  transferred to the zeroth pipe latch PL 0  is latched by any one of the pipelines P_LINE_ 1 , P_LINE_ 2  and P_LINE_ 3  included in the zeroth pipe latch PL 0  according to the pipeline input signals PIPE_IN_ 1 , PIPE_IN_ 2  and PIPE_IN_ 3 , and the data D 8  of the eighth data input/output pad DQ 8  transferred to the eighth pipe latch PL 8  is latched by any one of the pipelines P_LINE_ 1 , P_LINE_ 2  and P_LINE_ 3  included in the eighth pipe latch PL 8  according to the pipeline input signals PIPE_IN_ 1 , PIPE_IN_ 2  and PIPE_IN_ 3 . 
     In this way, the data D 0  of the zeroth data input/output pad DQ 0  latched by the zeroth pipe latch PL 0  is transferred to the zeroth driver DRV 0  included in the first driving units  720 A and  720 C according to the toggling of the first pipeline output signals PIPE_OUT_UP_ 1 , PIPE_OUT_UP_ 2  and PIPE_OUT_UP_ 3 . 
     Furthermore, the data D 8  of the eighth data input/output pad DQ 8  latched by the eighth pipe latch PL 8  is output to the eighth driver DRV 8  included in the second driving units  720 B and  720 D and is transferred to the third bank group  700 C according to the toggling of the second pipeline output signals PIPE_OUT_DN_ 1 , PIPE_OUT_DN_ 2  and PIPE_OUT_DN_ 3 . 
     That is, in a case where the predetermined place in which the data D 0  of the zeroth data input/output pad DQ 0  should be stored is included in the zeroth bank group  700 A, control is performed for the first pipeline output signals PIPE_OUT_UP_ 1 , PIPE_OUT_UP_ 2  and PIPE_OUT_UP_ 3  to be toggled. In a case where the predetermined place in which the data D 0  of the zeroth data input/output pad DQ 0  should be stored is included in the third bank group  700 C, control is performed for the second pipeline output signals PIPE_OUT_DN_ 1 , PIPE_OUT_DN_ 2  and PIPE_OUT_DN_ 3  to be toggled. 
     In the structure of the DRAM for the graphics device capable of easily changing the data input/output bandwidth in accordance with the second embodiment having the above-described configuration, it can be seen that the first driving units  720 A and  720 C drive the data D 0 , D 1 , D 2 , D 3 , D 4 , D 5 , D 6 , D 7 , D 16 , D 17 , D 18 , D 19 , D 20 , D 21 , D 22  and D 23  latched by the first pipe latch groups  730 A and  730 C to transfer them to the first and third bank groups  700 A and  700 C corresponding to the first pad groups  760 A and  760 C, and are disposed relatively near the first and third bank groups  700 A and  700 C. Moreover, it can be seen that the second driving units  720 B and  720 D drive the data D 0 , D 1 , D 2 , D 3 , D 4 , D 5 , D 6 , D 7 , D 8 , D 9 , D 10 , D 11 , D 12 , D 13 , D 14 , D 15 , D 16 , D 17 , D 18 , D 19 , D 20 , D 21 , D 22 , D 23 , D 24 , D 25 , D 26 , D 27 , D 28 , D 29 , D 30  and D 31  latched by the second pipe latch groups  730 B and  730 D to transfer them to the second and fourth bank groups  700 B and  700 D corresponding to the second pad groups  760 B and  760 D, and are disposed relatively near the first and third bank groups  700 A and  700 C. 
     Accordingly, although the first driving units  720 A and  720 C and the second driving units  720 B and  720 D have a relatively weak driving power, they can stably transfer the data. Moreover, since the first driving units  720 A and  720 C and the second driving units  720 B and  720 D have a relatively weak driving power, they can consume only a low current. 
     In a case where the second embodiment is applied as described above, the DRAM for the graphics device capable of changing the data input/output bandwidth includes the pipe latches which can latch the data input through the data input/output pads, and transfers the selectively latched data to the internal banks according to the change of the data input/output bandwidth, thereby consuming a minimum amount of current regardless of the change of the data input/output bandwidth. 
     The DRAM for the graphics device capable of changing the data input/output bandwidth includes the data driving units which can drive data input through the data input/output pads by a driving power corresponding to the data input/output option value DATA_IO_OP to transfer the data to the internal banks, thereby consuming a minimum amount of current regardless of the change of the data input/output bandwidth. 
     The DRAM for the graphics device capable of changing the data input/output bandwidth includes the pipe latches which can latch data input through the data input/output pads, thereby consuming a minimum amount of current regardless of the change of the data input/output bandwidth. 
     While the present invention has been described with respect to the specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims. 
     For example, DRAMs for the graphics device in accordance with the embodiments of the present invention basically have the X32 data input/output bandwidth and may have the X16 data input/output bandwidth according to the change of the data input/output bandwidth, which is for convenience. That is, the spirit and scope of the present invention include a case where the DRAMs for the graphic have the data input/output bandwidth larger or smaller than the X32 data input/output bandwidth, and also include a case where the DRAMs for the graphic have the data input/output bandwidth larger or smaller than the X16 data input/output bandwidth according to the change of the data input/output bandwidth.