THS4130CDG4 Datasheet, PDF (18/36 Pages) Texas Instruments – HIGH-SPEED, LOW-NOISE, FULLY-DIFFERENTIAL I/O AMPLIFIERS

THS4130
THS4131
SLOS318H – MAY 2000 – 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.
V_IN− ^R(g)
Vs
V_IN+
R_(g)
R_f
V_CC+
−+
+−
V_OCM
V_CC−
V_O+
V_O−
R_f
Note: For proper operation, maintain symmetry by setting
R_f1 = R_f2 = R_f and R_(g)1 = R_(g)2 = R_(g) ⇒ A = R_f/R_(g)
Figure 37. Amplifying Differential Signals
V_IN− ^R(g)
V_IN+
R_(g)
Vs
R_f
V_CC+
−+
V_O+
+−
V_O−
V_OCM
V_CC−
RECOMMENDED RESISTOR VALUES
GAIN
1
2
5
10
R_(g) Ω
390
374
402
402
R_f Ω
390
750
2010
4020
R_f
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
+
–
1
2
VI
(12)
18
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