A Trimming-Free 3-in-1 Multi-Mode Passive Switched-Capacitor Amplifier With an Absolute Logarithmic Error of 0.5 dB up to 200 ^◦C

This work presents a 3-in-1 multi-mode amplifier, including automatic gain control (AGC) and logarithmic gain, which achieves a total gain of 9.5–85.5 dB and an input-referred noise (IRN) of 4.7 µVrms within a bandwidth of 136 kHz. The PVT-focused amplifier design operates from −25 ^◦C to 200 ^◦C and does not require any trimming. Incorporating a parallel piecewise logarithmic approximation using nine passive-switched-capacitor (PSC) stages with a fixed gain of three (0.015 dB error per stage), the temperature stable absolute logarithmic error is 0.5 dB. This leads to a logarithmic conformity error (LCE) of 0.75 % up to 200 ^◦C.