An 80 MHz Bandwidth and 26.8 dBm OOB IIP3 Transimpedance Amplifier with Improved Nested Feedforward Compensation and Multi-Order Filtering

This paper presents a wideband and highly linear transimpedance amplifier (TIA) with a high-speed, current-efficient transconductance amplifier and multi-order filtering. The proposed TIA employs a Rauch biquad structure and incorporates an operational transconductance amplifier with an improved feedforward frequency compensation in a nested configuration. The Rauch biquad TIA architecture improves the out-of-band (OOB) selectivity, achieving a high OOB IIP3 of the TIA. The proposed feedforward compensation scheme is effective only at high frequencies and thus further enhances the gain bandwidth product of the transconductance amplifier. The current re-use technique improves the power efficiency of the feedforward stage. The prototype circuit was designed in the TSMC 65nm CMOS technology. The TIA achieves a bandwidth of 80 MHz and an OOB IIP3 of 26.8 dBm with a power consumption of 14.2 mW from a supply of 1.8 V while occupying a core area of 0.037 mm2.