Reference buffer choice for AD7984

Question

Hi, 
 Are there any recommended opamp for the buffer of the AD7984 reference? My reference chip is ADR434. I'm considering AD8628 now, but I'm afraid of the low GBP of it. 
 
 Thanks. 
 
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andreialejandro · Accepted Answer

Hi, 
 The external reference option of the AD7984 has a dynamic input impedance and should therefore be driven by a low-impedance source with efficient decoupling between the REF and GND pins. Checking the compatibility of the reference buffer that you are planning to use which is the AD8628 to the specified parameters of the AD7984 SAR ADC, in terms of voltage swing, load current, and input-output resistances I can conclude that your chosen reference buffer is compatible to the ADC. Regarding the gain bandwidth product, the dynamic performance of the op-amp AD8628 is not that significant because the signal input and the buffered output is only DC signal. Below is the configuration of the reference, reference buffer, and ADC. 
 
 Regards, 
 Andrei)

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Reference buffer choice for AD7984