FUNCTION CHANGING CIRCUIT OF SEMICONDUCTOR MEMORY DEVICE

摘要

PURPOSE: A function changing circuit is provided to be capable of parsing and verifying a device via a test mode after fabricating a semiconductor memory device. CONSTITUTION: A test mode decoder(310) receives an address(ADDR), address strobe signals(RASB, CASB), and control signals(CSB, WEB) to output test mode signals(T1-Tn), a clock signal(TCLK) and a reset signal(TRST). A counter part(320) counts the clock signal(TCLK) to output count signals(Q1-Q3), and clears a count value in response to the reset signal(TRST). A logic gate part(330) logically combines respective input signals(Vi31-Vi33) and the outputs(Q1-Q3) of the counter part(320), and outputs final output signals(Vo31-Vo33).