High-speed BiCMOS operational amplifier for switched-capacitor circuits

A high-speed fully-differential operational amplifier (op-amp) realized in 2-/spl mu/ BiCMOS technology is proposed. Input MOS buffers allow the use of this op-amp in switched capacitor (SC) circuits with high clock frequency (up to 75 MHz). The gain stage is realized with resistively-loaded bipolar devices. No common mode feedback is required. This saves area and power and increases speed. The op-amp presents a DC gain of about 46 dB with a unity-gain frequency as large as 700 MHz with 1.5 pF load. The measured performance of closed-loop settling time (1%) is about 12 ns.<>