ADA4940-1 AD [Analog Devices], ADA4940-1 Datasheet - Page 20

• Manufacturer Part Number: ADA4940-1
• Description: Ultralow Power, Low Distortion
• Manufacturer: AD [Analog Devices]

ADA4940-1/ADA4940-2
TERMINOLOGY
DEFINITION OF TERMS
Differential Voltage
Differential voltage refers to the difference between two node
voltages. For example, the differential output voltage (or
equivalently, output differential mode voltage) is defined as
where V
−OUT terminals with respect to a common reference.
Similarly, the differential input voltage is defined as
Common-Mode Voltage (CMV)
CMV refers to the average of two node voltages. The output
common-mode voltage is defined as
Similarly, the input common-mode voltage is defined as
+V
+D
–D
OCM
IN
IN
V
V
V
V
OUT, dm
IN, dm
OUT, cm
IN, cm
+OUT
R
R
= (+D
= (+D
G
G
R
R
= (V
= (V
and V
F
F
+OUT
+OUT
IN
IN
−OUT
–FB
+IN
–IN
+FB
+ (−D
− (−D
Figure 61. Circuit Definitions
+ V
− V
refer to the voltages at the +OUT and
−OUT
−OUT
ADA4840-1/
IN
IN
ADA4940-2
))/2
))
)/2
)
–OUT
+OUT
R
V
L, dm
OUT, dm
Rev. B | Page 20 of 32
–
+
Common-Mode Offset Voltage
The common-mode offset voltage is defined as the difference
between the voltage applied to the V
common mode of the output voltage.
Differential V
The differential mode and common-mode voltages each have
their own error sources. The differential offset (V
voltage error between the +IN and −IN terminals of the amplifier.
Differential CMRR reflects the change of V
changes to the common-mode voltage at the input terminals
+D
V
changes to the common-mode voltage at the output terminals.
Balance
Balance is a measure of how well the differential signals are
matched in amplitude; the differential signals are exactly 180°
apart in phase. By this definition, the output balance is the
magnitude of the output common-mode voltage divided by
the magnitude of the output differential mode voltage.
OCM
IN
V
CMRR
CMRR
Output
and −D
CMRR reflects the change of V
OS, cm
= V
V
DIFF
OCM
IN
Balance
.
OUT, cm
OS
=
=
, Differential CMRR, and V
ΔV
ΔV
ΔV
ΔV
− V
OS,
OS,
OCM
IN,
Error
dm
cm
dm
OCM
=
V
V
OUT
OUT
,
,
dm
cm
OCM
OS, dm
terminal and the
in response to
OS, dm
OCM
Data Sheet
in response to
OS, dm
CMRR
) is the