Reference clock complementary metal-oxide semiconductor (cmos) input buffer with self-calibration and improved electrostatic discharge (esp) performance

Abstract

Reference clock CMOS input buffer with self-calibration and improved ESD performance. In one embodiment, a reference clock input buffer of an image sensor includes a Schmitt trigger configured to generate a clock signal having a falling edge and a rising edge. The falling edge and the rising edge are separated by a hysteresis voltage. The Schmitt trigger includes a plurality of output switches and a plurality of voltage control switches that are individually coupled to individual output switches [M-i] of the plurality of output switches. Voltage of the falling edge signal or the rising edge signal of the Schmitt trigger is adjustable by selectively switching at least one voltage control switch of the plurality of voltage control switches.