Patent ID: 6011500
Filing Date: 2000-01-04
Classification: H03M

Abstract:
An integrated circuit with a built-in D/A converter, comprising:digital signal processing means for performing predetermined processing of a digital signal input thereto and for outputting a digital signal;clock signal generating means for generating clock signals;a counter for counting said clock signals generated by said clock signal generating means and outputting a digital signal representative of its count value, said counter being responsive to a count mode switching signal to switch between a count mode in which to repeat counting up said clock signals and a count mode in which to repeat counting down said clock signals;a selector responsive to a select signal to selectively output either one of said digital signal from said digital signal processing means and said digital signal from said counter;a D/A converter for converting said digital signal output from said selector to an analog signal; andcontrol means which, when supplied with a test enable signal to start testing of said D/A converter, outputs a select signal for controlling said counter to start its counting operation and said selector to select and output said digital signal from said counter and, upon counting a predetermined number of clock signals, applies said count mode switching signal to said counter to switch it from one count mode to the other.