AD7794 External Voltage

Question

Hello 
 I want to use an external voltage of 3.3V for AD7794 to fully capture the signal. 
 Which voltage reference component you suggest me to choose? 
 And should I connect the REFIN- pin to the GND? 
 
 Thank you.

FormerMember · Accepted Answer

This was answered on another thread, so i copied it and pasted it below. 
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 Hi cevdet29, 
 The AD7794 suggests the use of ADR391 and ADR381 which are 2.5 V micropower low noise voltage reference. 
 For 3.3V, I suggest you use the ADR4533 which is ultra-low noise but has Is=950uA compared to the ADR391 with Is=120uA. 
 Yes you can connect the REFIN- pin to GND. 
 Btw the external reference can only accept 3.3V when AVdd is powered at 3.3V 
 Hope this helps. 
 ACatapang 
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AD7794 External Voltage