PSRR of AD8622

Document created by analog-archivist Employee on Feb 23, 2016
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On pages 3/4 of the data sheet, a minimum PSRR of 125 dB @ 25°C is specified,
whereas in Figs. 29/32 the PSRR apparently settles to slightly above 100 dB
below 10 Hz. Could you please explain the reason for this discrepancy?

 

The specs table show the large signal PSRR at dc. Basically, we test for Vos1
at +/-2V, then test Vos2 at +/-18V. PSRR = delta Vsy / delta Vos.

The figures show small signal ac PSRR at different frequencies. Vsy is
modulated by a small amount of ac voltage to measure the amplifier’s ability in
rejecting any change in Vsy.

This article can give a brief explanation on the difference:
http://www.analog.com/library/analogdialogue/archives/45-04/op_amp_measurements.
html

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