High performance data acquisition signal chains used for spectroscopy, magnetic resonance imaging (MRI), gas chromatography, and vibration, oil/gas, and seismic systems demand a state-of-the-art, high dynamic range (DR) while addressing difficult thermal design, space, and cost challenges.

One of the ways to achieve a higher dynamic range is to oversample the converter to accurately monitor and measure both small and large input signals from the sensors. There are a number of other ways to increase the dynamic range of an analog-to-digital converter (ADC), such as using programmable gain amplifiers or operating multiple ADCs in parallel and digital postprocessing the output to get the averaged result. However, some designers may find these methods cumbersome or impractical to implement for their systems, mainly due to power, space, and cost constraints.

This application note focuses on the oversampling of high throughput, 5 MSPS, 18-bit/16-bit precision successive approximation register (SAR) converters by implementing a straightforward averaging of ADC output samples to increase the dynamic range.