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KH231
Fast Settling, Wideband Buffer/Amplifier (Av = 鹵1 to 鹵5)
Features
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General Description
The KH231 Buffer/Amplifier is a wideband operational
amplifier designed specifically for high-speed, low-
gain applications. The KH231 is based on a current
feedback op amp topology-a unique design that both
eliminates the gain-bandwidth tradeoff and permits
unprecedented high-speed performance. (See table below.)
The KH231 Buffer/Amplifier is the ideal design alter-
native to low precision open-loop buffers and oscillation-
prone conventional op amps. The KH231 offers precise
gains from 鹵1.000 to 鹵-5.000 and linearity that is a
true 0.1%-even for demanding 50鈩?loads. Open-loop
buffers, on the other hand, offer a nominal gain of
0.95 鹵0.03 and a linearity of only 3% for typical loads.
A buffer鈥檚 settling time may look impressive but it is
usually specified at unrealistically large load resis-
tances or when the effects of thermal tail are not
included; the KH231 Buffer/Amplifier settles to 0.05%
in 15ns-while driving a 100鈩?load.
Offsets and drifts, usually a low priority in conven-
tional high-speed op amp designs, were not ignored
in the KH231; the input offset voltage is typically 1mV
and input offset voltage drift is only 10碌V/擄C. The
KH231 is stable and oscillation-free across the entire
gain range and since it鈥檚 internally compensated, the
user is saved the trouble of designing external com-
pensation networks and having to 鈥渢weak鈥?them in
production. The absence of a gain-bandwidth trade-
off in the KH231 allows performance to be predicted
easily; the table below shows how the bandwidth is
affected very little by changing the gain setting.
The KH231 is constructed using thin film resistor/bipolar
transistor technology, and is available in the following
versions:
The KH231 is constructed using thin film resistor/bipolar
transistor technology, and available in these versions:
KH231AI
KH231AK
KH231AM
-2
-5
Units
MHz
ns
V/ns
ns
165MHz closed-loop 鈥?-3dB bandwidth
15ns settling to 0.05%
1mV input offset voltage, 10碌V/擄C drift
100mA output current
Excellent AC and DC linearity
Direct replacement for CLC231
Applications
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Driving flash A/D converters
Precision line driving
(a gain of 2 cancels matched-line losses)
DAC current-to-voltage conversion
Low-power, high-speed applications (50mW @ 鹵5V)
Small Signal Pulse Response
Output Voltage (400mV/div)
A
v
= 2
A
v
= -2
Time (5ns/div)
Bottom View
I
CC
Adjust
Case
ground
GND
7
Adjust -V
CC
8
9
-V
CC
V+ 6
10
Collector
Supply
Output
Supply
Voltage
Non-Inverting
Input
Inverting
Input
Not
Connected
+
V- 5
NC 4
3
Case
ground
GND
2
4
4
-
11 V
o
12
+V
CC
Collector
Supply
1
Supply
Voltage
Adjust +V
CC
I
CC
Adjust
Pins 2 and 8 are used to adjust the supply current or to adjust the off-
set voltage (see text). These pins are normally left unconnected.
-25擄C to +85擄C
-55擄C to +125擄C
-55擄C to +125擄C
Typical Performance
Gain Setting
Parameter
1
2
5
-1
-3dB bandwidth
180 165 130
rise time (2V)
1.8 2.0 2.5
slew rate
2.5 3.0 3.0
settling time (to 0.1%) 12 12 12
165 150 115
2.0 2.2 2.9
3.0 3.0 3.0
12 12 15
KH231HXC
KH231HXA
-55擄C to +125擄C
-55擄C to +125擄C
12-pin TO-8 can
12-pin TO-8 can, features
burn-in & hermetic testing
12-pin TO-8 can,
environmentally
screened and electrically
tested to MIL-STD-883
SMD#: 5962-8959401HXC
SMD#: 5962-8959401HXA
REV. 1A February 2001
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