ADA4930-1/ADA4930-2

Data Sheet

Rev. B | Page 16 of 25

OPERATIONAL DESCRIPTION

DEFINITION OF TERMS

+IN

–IN

+OUT

–OUT

–FB

+FB

ADA4930

Figure 42. Circuit Definitions

Differential Voltage

Differential voltage refers to the difference between two

node voltages. For example, the output differential voltage (or,

equivalently, output differential-mode voltage) is defined as

−OUT terminals with respect to a common reference.

Common-Mode Voltage

Common-mode voltage refers to the average of two node voltages.

The output common-mode voltage is defined as

Balance

Output balance is a measure of how close the differential signals are

to being equal in amplitude and opposite in phase. Output balance

is most easily determined by placing a well-matched resistor

divider between the differential voltage nodes and comparing the

magnitude of the signal at the divider midpoint with the magnitude

of the differential signal (see Figure 39). By this definition, output

balance is the magnitude of the output common-mode voltage

divided by the magnitude of the output differential mode voltage.

dm

OUT

cm

OUT

V

V

Error

Balance

Output

,

,

