SBAS603B April 2013 – November 2020 ADS4449
PRODUCTION DATA
To ensure a low-noise, common-mode reference, the VCM terminal should be filtered with a 0.1-µF, low-inductance capacitor connected to ground. The VCM terminal is designed to directly bias the ADC inputs (refer to Figure 9-4 to Figure 9-7).
Each ADC input terminal sinks a common-mode current of approximately 1.5 µA per MSPS of clock frequency. When a differential amplifier is used to drive the ADC (with dc-coupling), ensure that the output common-mode of the amplifier is within the acceptable input common-mode range of the ADC inputs (VCM ± 25 mV).