R
I
/
Error Out
2kΩ
OPA627
R
I
, R
1
C
F
Error Band
(0.01%)
2kΩ
6pF
±0.5mV
OPA637
500Ω
4pF
±0.2mV
C
F
HP-
5082-
2835
2kΩ
+15V
R
I
–
High Quality
Pulse Generator
51Ω
±5V
Out
+
NOTE: C
F
is selected for best settling time performance
depending on test fixture layout. Once optimum value is
determined, a fixed capacitor may be used.
–15V
FIGURE 11. Settling Time and Slew Rate Test Circuit.
Gain = 100
CMRR
≈
116dB
Bandwidth
≈
1MHz
2
25kΩ
INA105
Differential
Amplifier
3
–
+In
+
R
F
5kΩ
OPA637
Differential Voltage Gain = 1 + 2R
F
/R
G
25kΩ
1
25kΩ
5
–In
+
–
OPA637
R
F
5kΩ
Input Common-Mode
Range = ±5V
R
G
101Ω
3pF
–
+
25kΩ
6
Output
FIGURE 12. High Speed Instrumentation Amplifier, Gain = 100.
Gain = 1000
CMRR
≈
116dB
Bandwidth
≈
400kHz
2
10kΩ
INA106
Differential
Amplifier
3
–
R
F
5kΩ
OPA637
10kΩ
1
100kΩ
5
–In
+
–
OPA637
R
F
5kΩ
Input Common-Mode
Range = ±10V
R
G
101Ω
3pF
–
+
100kΩ
6
Output
+In
+
Differential Voltage Gain = (1 + 2R
F
/R
G
) • 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.
R
2
–
A
1
V
I
+
+
*Minimize capacitance at this node.
V
O
–
OPA603
R
1
R
3
*
R
L
≥
150Ω
for ±10V Out
GAIN
(V/V)
100
1000
A
1
OP AMP
OPA627
OPA637
R
1
(Ω)
50.5
(1)
49.9
R
2
(kΩ)
4.99
4.99
R
3
(Ω)
20
12
R
4
(kΩ)
1
1
–3dB
(MHz)
15
11
SLEW RATE
(V/
µ
s)
700
500
R
4
NOTE: (1) Closest 1/2% value.
FIGURE 14. Composite Amplifier for Wide Bandwidth.
®
13
OPA627, 637
TI [ TEXAS INSTRUMENTS ]
