A DC-Coupled, HBT-Based Transimpedance Amplifier for the LISA Quadrant Photoreceivers

The quadrant photoreceivers (QPRs) in the Laser Interferometer Space Antenna (LISA) mission must feature an input-referred current noise below 2 pAHz^\frac{-1}{2} at 25 MHz to avoid degradation of the signal-to-noise ratio. We present a QPR with a dc-coupled transimpedance amplifier (TIA) based on heterojunction bipolar transistors (HBTs). The QPR features an input-referred current noise density below 1.5 pAHz^\frac{-1}{2} at 25 MHz, a 37 MHz bandwidth, and a 56.2 mW power consumption. Additionally, the dc-coupled, HBT-based TIA allows the QPR to fulfill the size and interface requirements of the LISA mission.