A binary-weighted 64-dB programmable gain amplifier with a DCOC and AB-class buffer

This paper designs a binary-weighted programmable gain amplifier(PGA) with a DC offset cancellation (DCOC) circuit and an AB-class output buffer.The PGA adopts the circuit topology of a differential amplifier with diode-connected loads.Simulation shows that the performance of the PGA is not sensitive to temperature and process variation.According to test results,controlled by a digital signal of six bits,the PGA can realize a dynamic gain of-2 to 61 dB,and a gain step of 1 dB with a step error within±0.38 dB.The minimum 3 dB bandwidth is 92 MHz.At low-gain mode,IIP3 is 17 dBm,and a 1 dB compression point can reach 5.7 dBm.The DCOC circuit enables the amplifier to be used in a direct-conversion receiver and the AB-class output buffer circuit reduces the overall static power consumption.