ADA4932-1YCPZ-R71 datasheet(19/28 Pages) AD

19 / 28 page

ADA4932-1/ADA4932-2

Rev. A | Page 19 of 28

THEORY OF OPERATION

The ADA4932-x differs from conventional op amps in that it

has two outputs whose voltages move in opposite directions and

an additional input, VOCM. Like an op amp, it relies on high open-

loop gain and negative feedback to force these outputs to the

desired voltages. The ADA4932-x behaves much like a standard

voltage feedback op amp and facilitates single-ended-to-differential

conversions, common-mode level shifting, and amplifications of

differential signals. Like an op amp, the ADA4932-x has high input

impedance and low output impedance. Because it uses voltage

feedback, the ADA4932-x manifests a nominally constant gain

bandwidth product.

Two feedback loops are employed to control the differential and

common-mode output voltages. The differential feedback, set

with external resistors, controls only the differential output voltage.

The common-mode feedback controls only the common-mode

output voltage. This architecture makes it easy to set the output

common-mode level to any arbitrary value within the specified

limits. The output common-mode voltage is forced, by the internal

common-mode feedback loop, to be equal to the voltage applied

to the VOCM input.

The internal common-mode feedback loop produces outputs

that are highly balanced over a wide frequency range without

requiring tightly matched external components. This results in

differential outputs that are very close to the ideal of being

identical in amplitude and are exactly 180° apart in phase.

ADA4932-1YCPZ-R71 数据表(PDF) 19 Page - Analog Devices