1 Introduction

The OPAx328 family of high-speed, precision amplifiers with low (about 45 Ω), flat output impedance from 1 kHz to 10 MHz, which is critical for driving large capacitive loads, makes these op amps not only an excellent option for buffering of voltage references but also for driving high-resolution analog-to-digital converters (ADCs). Additionally, due to their ultra-low input bias current, IB, over a wide temperature range, OPAx328 devices are a great choice for high-input impedance, single-supply applications, like trans-impedance gain amplifier (TIA), enabling precision measurement of photo-currents below 1 nA.