Datasheet

Single-Ended to Fully Differential Application
3-3
THS4504EVM Applications
3.2 Single-Ended to Fully Differential Application
Single-supply, single-ended to fully differential conversion is a popular
application for fully differential amps. Until the introduction of fully differential
amps such as the THS4504, it was necessary to include two coupling
capacitors to prevent the input signal from violating the input common mode
range of the op amp. The THS4504 is optimized for ground-referenced inputs
in single supply applications—no capacitors are required.
Figure 3−2. Single Supply Operation
J2
Vout+
R2
487
W
−
Vocm
+
U1
THS4504
1
8
2
3
6
5
4
R17
0
J3
Vout −
R3
523
W
R5
R4
499
W
+VS
TP1
Vocm
C2 0
J1
Vin−
R6 0
R1
54.9
W
C1 0
R7 0
499
W
When operated, the the output voltage is offset to +VS/2 (2.5 V) by the internal
action of V
OCM
.
Figure 3−3. Output of a Ground Referenced, Single-Supply Application
Note that a small offset is present on the input voltage. This is caused by a
voltage divider formed by R2 + R4 and the parallel combination of R1 and the
source resistance of the signal generator.