The ADS79xx can operate with an external 2.5-V ± 10-mV reference. A clean, low noise, well-decoupled reference voltage on the REFP pin is required to ensure good performance of the converter. A low noise band-gap reference like the REF5025 can be used to drive this pin. A 10-μF ceramic decoupling capacitor is required between the REFP and REFM pins of the converter. The capacitor should be placed as close as possible to the pins of the device.