A broadband fully differential amplifier in InP DHBT using global shunt-shunt feedback

Abstract

This paper presents a broadband fully differential amplifier using a 0.8-μm InP DHBT process, exhibiting a bandwidth exceeding 8GHz from DC and achieves a differential gain of 14.56dB, occupying 0.78mm × 0.7mm with all pads involved and consuming only 375mW with a -5V power supply. The core of the design leverages an operational amplifier with Cherry-Hooper architecture, incorporating global shunt-shunt feedback to ensure high gain linearity across the bandwidth. Notably, the -1dB bandwidth of this circuit extends up to 5GHz. Additionally, the design is entirely devoid of inductors, resulting in a consistent gain profile without any significant gain peaking.