We have purchased some units of the AD8495 and we are about to test its performance. So I downloaded the CN0271 reference design:
And I can't make much sense of this +2.5V going to IN- input of AD8476 (pin 1). It can be seen on the schematic:
And on the ref. design webpage:
BOM confirms that R5 is a short and is populated:
Since the AD8476 is just a differential amplifier, unity gain, its differential output should be (AD8495 output ) - 2.5V. However, the AD8495 reference is grounded, and its output equation is:
Considering the whole board is based on a single +5V supply, that looks a bit awkward.
It looks to me that pin 1 should be grounded. AD8476 main purpose seems to be just convert the single ended output from the AD8495 to a differential signal and drive the ADC. Most of the common-mode is already addressed by the instrumentation amplifier, anyway.
But I am probably missing something here, since I believe this is a tested circuit. Could you advise?