Differential Bloch Oscillating Transistor Pair

TL;DR

This paper investigates a differential Bloch Oscillating Transistor pair for cryogenic low-noise measurements, demonstrating effective common mode rejection and excellent noise performance at high source impedances.

Contribution

It introduces a differential stage using a pair of Bloch Oscillating Transistors and characterizes its noise and common mode rejection capabilities.

Findings

Common mode rejection ratio ~20 dB

Excellent noise performance at MΩ source impedances

Effective differential measurement at cryogenic temperatures

Abstract

We examine a Bloch Oscillating Transistor pair as a differential stage for cryogenic low-noise measurements. Using two oppositely biased, nearly symmetric Bloch Oscillating Transistors, we measured the sum and difference signals in the current gain and transconductance modes while changing the common mode signal, either voltage or current. From the common mode rejection ratio we find values $\sim 20$ dB even under non-optimal conditions. We also characterize the noise properties and obtain excellent noise performance for measurements having source impedances in the M$\Omega$ range.