Datasheet

Single-Ended to Fully Differential Application
3-3
THS4501EVM Applications
Figure 3−2. Single Supply Operation
J2
Vout+
R2
374
W
−
Vocm
+
U1
THS4501
1
8
2
3
6
5
4
R17
0
J3
Vout−
R3
402
W
R5
392
W
C13
1
m
F
R4
392
W
+VS
TP1
Vocm
C2 0
J1
Vin−
R6 0
R1
56.2
W
C1 0
R7 0
Figure 3−3. Output of a Ground Referenced, Single-Supply Application
3
2
1
0
−1
0 500 n 1 Ω
t − Time − s
Volts
Note that a small offset is present on the input voltage. This is caused by a volt-
age divider formed by R2 + R4 and the parallel combination of R1 and the
source resistance of the signal generator.
This application circuit has interaction between R
source
, R
termination
, and R
g
.
Texas Instruments has provided an engineer design utility to facilitate the
design of these circuits. Engineer design utilities are available on the
Amplifiers and Comparators section of the Analog and Mixed Signal portion of
the TI web page.
The designer should be aware that each individual feedback path is an invert-
ing path. There is no noninverting gain circuit for fully differential amps. The
designer should also be aware that the gain is affected by the open loop char-
acteristic of the FDA, the same assingle-endedop amps. If there is sufficient
safety margin between the closed loop response and open loop response of
the FDA (40 dB or more), the error contribution from the open loop response of
the FDA is negligible and can be ignored.