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THS4131 Datasheet, PDF (18/37 Pages) National Semiconductor (TI) – HIGH-SPEED, LOW-NOISE, FULLY-DIFFERENTIAL I/O AMPLIFIERS | |||
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THS4130
THS4131
SLOS318H â MAY 2000 â REVISED MAY 2011
www.ti.com
Figure 37 and Figure 38 depict the differences between the operation of the THS413x fully-differential amplifier in
two different modes. Fully-differential amplifiers can work with differential input or can be implemented as single
in/differential out.
VINâ R(g)
Vs
VIN+
R(g)
Rf
VCC+
â+
+â
VOCM
VCCâ
VO+
VOâ
Rf
Note: For proper operation, maintain symmetry by setting
Rf1 = Rf2 = Rf and R(g)1 = R(g)2 = R(g) â A = Rf/R(g)
Figure 37. Amplifying Differential Signals
VINâ R(g)
VIN+
R(g)
Vs
Rf
VCC+
â+
VO+
+â
VOâ
VOCM
VCCâ
RECOMMENDED RESISTOR VALUES
GAIN
1
2
5
10
R(g) â¦
390
374
402
402
Rf â¦
390
750
2010
4020
Rf
Figure 38. Single In With Differential Out
If each output is measured independently, each output is one-half of the input signal when gain is 1. The
following equations express the transfer function for each output:
VO
+
1
2
VI
(11)
The second output is equal and opposite in sign:
VO
+
â
1
2
VI
(12)
18
Copyright © 2000â2011, Texas Instruments Incorporated
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