Patent ID: 8243540

Claim:
A semiconductor memory device comprising: a memory cell array outputting at least one of a first and a second data group at a first data rate; an output circuit, wherein the output circuit, in a normal mode of operation, serially outputs at least one of the first and the second data group at the first data rate, and in a first test mode outputs the first data group at a second data rate, in a second test mode outputs the second data group at the second data rate, and in a third test mode outputs the first data group or the second data group at the second data rate in response to at least one control signal; and a test mode set circuit outputting a first, a second and a third test mode signal for respectively determining the first, second and third test mode of the output circuit, in response to a plurality of input signals, wherein the output circuit includes, a selecting section, wherein the selection section outputs at least one selection signal for selecting the first data group or the second data group, in response to at least the control signal, at least two of the first, second or third test mode signals, and the internal read signal, wherein the selecting section includes, a first sub-selecting section that performs a first logic operation on an inverted signal of the control signal, at least one test mode signal of the at least two test mode signals, and the internal read signal, and performs a second logic operation on the output of the first logic operation and at least one another test mode signal of the at least two test mode signals, the first sub-selecting section outputting a first selection signal based on the first and second logic operations, and a second sub-selecting section that performs a third logic operation on the control signal, at least one test mode signal of the at least two test mode signals, and the internal read signal, and performs a fourth logic operation on the output of the third logic operation and at least one another test mode signal of the at least two test mode signals, the second sub-selecting section outputting a second selection signal based on the third and fourth logic operations; and a buffering section outputs the first data group in response to the first selection signal and outputs the second data group in response to the second selection signal.