Programmable impedance control circuit and method thereof

摘要

A programmable impedance control circuit for detecting a characteristic impedance of transmission line to thereby output it to an output driver and on-chip terminator in a semiconductor device. Particularly the circuit serves to control an internal impedance according to a controlled, programmable protocol irrespective of the changes in an external impedance due to factors such as voltage and temperature after an initial internal impedance is set during a locking operation.