AD9481 - Vref Capacitance

Question

The AD9481 datasheet mentions that a 10 uF bulk capacitor is required on the VREF pin when the internal fixed reference is used. It doesn't say what the maximum ESR for this capacitor should be. Is there a recommendation on how high the ESR can be for this capacitance? 
 Also, would there be any significant downsides to using a lower capacitance like 6.8 uF of 4.7 uF for this bulk capacitance? Which, if any, datasheet specs would be impacted by this?

PeeveeS · Accepted Answer

Hi ADriskell, Thanks for your interest in AD9481. The capacitors are there for stability when the internal VREF is used. Though we recommend that you use the same value indicated in the datasheet, you may use bulk capacitors ranging from 1uF to 100uF. You may also use capacitors in parallel to lower the effective ESR and increasing the capacitance. For the ESR, the lower the better. ESR <1ohm is a good criteria. Best regards, jsalenga

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AD9481 - Vref Capacitance

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