High speed voltage follower for standard BiCMOS technology

A new wideband low-distortion class A unitary gain voltage follower is presented in this brief. Based on a Gilbert's translinear loop of four transistors, the proposed topology only includes high frequency n-p-n transistors in signal paths. The circuit has been simulated under +/-1.5 V using the 0.8-mum BiCMOS technology from AMS. Simulation results confirm low output distortion and high frequency operation performances. For a total power consumption of only 3 mW, the -3-dB bandwidth of the voltage transfer function is higher than 2.5 GHz with a 1-k Omega loading resistance. The corresponding total harmonic distortion rate is lower than 0.06% when a 100-mV peak-to-peak input sinusoidal voltage is applied.