Features

Applications

(a gain of 2 cancels matched-line losses)

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 ±1.000 to ±-5.000 and linearity that is a

true 0.1%-even for demanding 50

Ω loads. Open-loop

buffers, on the other hand, offer a nominal gain of

0.95 ±0.03 and a linearity of only 3% for typical loads.

A buffer’s 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

Ω 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

µV/°C. The

KH231 is stable and oscillation-free across the entire

gain range and since it’s internally compensated, the

user is saved the trouble of designing external com-

pensation networks and having to “tweak” 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

-25°C to +85°C

12-pin TO-8 can

KH231AK

-55°C to +125°C

12-pin TO-8 can, features

burn-in & hermetic testing

KH231AM

-55°C to +125°C

12-pin TO-8 can,

environmentally

screened and electrically

tested to MIL-STD-883

KH231HXC

-55°C to +125°C

SMD#: 5962-8959401HXC

KH231HXA

-55°C to +125°C

SMD#: 5962-8959401HXA

KH231

Fast Settling, Wideband Buffer/Amplifier (Av = ±1 to ±5)

REV. 1A January 2004

Small Signal Pulse Response

Time (5ns/div)

K

Supply

Voltage

8

Adjust

7

GND

9

-V

CC

2

Adjust

3

GND

1

+V

CC

6

V+

5

V-

4

NC

10

-V

CC

V

o

+V

CC

11

12

4

4

Collector

Supply

Output

Collector

Supply

Supply

Voltage

Case

ground

Non-Inverting

Input

Inverting

Input

Not

Connected

Case

ground

+

-

Bottom View

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.

Typical Performance

Gain Setting

Parameter

1

2

5

-1

-2

-5

Units

-3dB bandwidth

180 165 130 165 150 115

MHz

rise time (2V)

1.8

2.0

2.5 2.0

2.2 2.9

ns

slew rate

2.5

3.0

3.0 3.0

3.0 3.0

V/ns

settling time (to 0.1%)

12

12

12

12

12

15

ns

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