A compact low-noise broadband digital picoammeter architecture

作者：Crescentini M; Tartagni M; Morgan H; Traverso P A

来源：Measurement, 2017, 100: 194-204.

DOI：10.1016/j.measurement.2016.12.040

• Ammeter
• Low-current measurement
• Current
• Leakage currents
• Charge-sensitive amplifier
• Low-noise amplifier
• Femto-ampere

A low-noise (<= 44 fA/root Hz), broadband (>= 100 kHz) compact architecture and related operation solutions are proposed for portable and low-cost time-domain acquisition of currents with effective resolution in the order of 1 pA and below. The front-end architecture is based on an integrating-differentiating scheme to achieve the optimal performance in terms of input-referred equivalent noise, but it overcomes the typical noise/bandwidth trade-off by making the sampling frequency of the AID conversion independent from the rate at which the analog front-end is reset. In order to strongly mitigate the main drawback, i.e., the introduction in the system of an inherent time-variance, a Track-and-Hold circuit synchronized with the reset is exploited. For validation purposes, a dual-channel prototype was implemented in a low-cost CMOS technology. The prototype is characterized by standard figures of merit and is experimentally validated by two simple case studies, which are typical of practical applications.

• 出版日期2017-3