In this article by Analog Devices’ Senior Staff Field Applications Engineer, Paul Perrault and Staff Applications and Marketing Engineer, Robert Kiely, they demonstrate that the best way to ensure humidity performance is to use hermetic packages like ceramic, and that conformal coatings can slow down the humidity effects within precision analog electronics. Along with following best practices this will ensure that your voltage reference itself won’t hold water, but instead will keep water out and preserve the performance you need in your precision design.
Voltage references serve a crucial role in precision analog systems, often setting the noise/resolution floor within an analog-to-digital converter (ADC) for precision measurement systems in instrumentation, test and measurement, and energy metering applications. For the design engineer, a supplier’s portfolio may include a bewildering array of silicon options. But among various voltage reference specifications (voltage noise, accuracy, drift, quiescent current, series vs. shunt, etc.) and their options for packaging (hermetic ceramic, plastic, die packaging), it’s worth assessing whether the end electronics product is actually performing as optimally as desired. There are many design pitfalls that could easily undermine the µV or nV accuracy noise target you were looking to achieve. Through a holistic view of the PCB manufacturing process, this article explores ways that a design engineer or PCB assembly engineer can protect against damaging environmental effects while preserving analog performance.