Datasheet

ADA4938-1/ADA4938-2
Rev. A | Page 18 of 28
TERMINOLOGY
ADA4938
+IN
–IN
+OUT
–OUT
–
FB
+FB
V
OCM
R
G
R
F
R
G
V
OUT, dm
R
L, dm
R
F
06592-004
Common-Mode Voltage
The common-mode voltage is the average of two node voltages.
The output common-mode voltage is defined as
V
OUT, cm
= (V
+OUT
+ V
−OUT
)/2
Balance
Balance is a measure of how well differential signals are matched in
amplitude and are exactly 180° apart in phase. 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 midpoint of the divider with
the magnitude of the differential signal. By this definition,
output balance is the magnitude of the output common-mode
voltage divided by the magnitude of the output differential
mode voltage.
Figure 57. Circuit Definitions
Differential Voltage
The differential voltage is 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.
dmOUT
cmOUT
V
V
ErrorBalanceOutput
,
,
=