Datasheet

ADA4930-1/ADA4930-2
Rev. A | Page 16 of 28
OPERATIONAL DESCRIPTION
DEFINITION OF TERMS
+IN
–IN
+OUT
–OUT
+D
IN
–
FB
+FB
–D
IN
V
OCM
R
G
R
F
R
G
V
OUT, dm
R
L, dm
R
F
ADA4930
09209-049
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
V
OUT, dm
= (V
+OUT
− V
−OUT
)
where V
+OUT
and V
−OUT
refer to the voltages at the +OUT and
−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
V
OUT, cm
= (V
+OUT
+ V
−OUT
)/2
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.
dmOUT
cmOUT
V
V
ErrorBalanceOutput
,
,
=