Error Out
RI/
2kΩ
OPA627
OPA637
CF
RI, R1
CF
Error Band
(0.01%)
2kΩ
6pF
±0.5mV
500Ω
4pF
±0.2mV
HP-
5082-
2835
2kΩ
+15V
RI
High Quality
–
+
NOTE: CF is selected for best settling time performance
depending on test fixture layout. Once optimum value is
determined, a fixed capacitor may be used.
±5V
Out
Pulse Generator
51Ω
–15V
FIGURE 11. Settling Time and Slew Rate Test Circuit.
Gain = 100
≈
CMRR 116dB
OPA637
–In
+
–
≈
Bandwidth 1MHz
RF
5kΩ
25kΩ
25kΩ
5
6
2
3
Input Common-Mode
Range = ±5V
INA105
Differential
Amplifier
RG
101Ω
3pF
Output
–
+
RF
5kΩ
25kΩ
25kΩ
–
+
1
+In
OPA637
Differential Voltage Gain = 1 + 2RF/RG
FIGURE 12. High Speed Instrumentation Amplifier, Gain = 100.
Gain = 1000
≈
CMRR 116dB
OPA637
–In
+
–
≈
Bandwidth 400kHz
RF
5kΩ
10kΩ
100kΩ
5
6
2
3
Input Common-Mode
Range = ±10V
INA106
Differential
Amplifier
RG
101Ω
3pF
Output
–
+
RF
5kΩ
10kΩ
100kΩ
–
+
1
+In
OPA637
Differential Voltage Gain = (1 + 2RF/RG) • 10
FIGURE 13. High Speed Instrumentation Amplifier, Gain = 1000.
This composite amplifier uses the OPA603 current-feedback op amp to
provide extended bandwidth and slew rate at high closed-loop gain. The
feedback loop is closed around the composite amp, preserving the
precision input characteristics of the OPA627/637. Use separate power
supply bypass capacitors for each op amp.
R2
–
A1
+
–
*Minimize capacitance at this node.
VI
+
VO
GAIN
(V/V)
A1
OP AMP
R1
(Ω)
R2
(kΩ)
R3
R4
–3dB
SLEW RATE
OPA603
R
L ≥ 150Ω
for ±10V Out
(Ω)
(kΩ) (MHz)
(V/µs)
R1
100
1000
OPA627
OPA637
50.5(1) 4.99
49.9 4.99
20
12
1
1
15
11
700
500
*
R3
R4
NOTE: (1) Closest 1/2% value.
FIGURE 14. Composite Amplifier for Wide Bandwidth.
®
13
OPA627, 637
TI [ TEXAS INSTRUMENTS ]
