AD7656ABSTZ datasheet(15/29 Pages) AD

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AD7656A

Data Sheet

Channel-to-Channel Isolation

Channel-to-channel isolation is a measure of the level of crosstalk

between any two channels. It is measured by applying a full-scale,

100 kHz sine wave signal to all unselected input channels and

determining the degree to which the signal attenuates in the

selected channel with a 30 kHz signal.

Power Supply Rejection Ratio (PSRR)

Variations in power supply affect the full-scale transition but

not the linearity of the converter. Power supply rejection is the

maximum change in the full-scale transition point due to a change

in power supply voltage from the nominal value. See the Typical

Performance Characteristics section.

Figure 15 shows the power supply rejection ratio vs. supply

ripple frequency for the AD7656A. The power supply rejection

ratio is defined as the ratio of the power in the ADC output at the

full-scale frequency, f, to the power of a 200 mV p-p sine wave

applied to the VDD and VSS supplies of the fSAMPLE of the ADC.

PSRR (dB) = 10 log (Pf/PfS)

where:

Pf is equal to the power at frequency f in the ADC output.

PfS is equal to the power at frequency fS coupled onto the VDD

and VSS supplies.

Percent Full-Scale Ratio (% FSR)

%FSR is calculated using the full theoretical span of the ADC.

Rev. 0 | Page 14 of 28

AD7656ABSTZ Datasheet(PDF) 15 Page - Analog Devices