The application of Infrared communication is very wide and IR transceiver has be-come a standard part of home entertainment equipment.
A preamplifier with single 5V supply had been designed for IR receiver module IC. As the distance between transmitter and receiver gets longer, the magnitude of input signal grows smaller. So to operate well at long distance, receiver IC should have high gain and low noise characteristics. Preamplifier must provide same magnitude of out-put signal, independent of distance. So gain limiting stages are needed. And to cut off DC noise component effectively, large resistance and capacitance are required. So many techniques are used to reduce IC size.
Transimpedance type preamplifier was designed, and diode limiting amplifier and current limiting amplifier was used. Current limiting amplifier has another function that make single input to differential output. AMS BiCMOS model was used in designing preamplifier, and both BJT version and MOS version was designed. Total power con-sumption is below 1mW and IC size is about 0.3㎟.
