SPT SPT231AIH, SPT231AMH Datasheet

Features

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165MHz closed-loop – -3dB bandwidth

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15ns settling to 0.05%

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1mV input offset voltage, 10µV/°C drift

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100mA output current

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Excellent AC and DC linearity

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Direct replacement for CLC231

Applications

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Driving flash A/D converters

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Precision line driving
(a gain of 2 cancels matched-line losses)

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DAC current-to-voltage conversion

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Low-power, high-speed applications
(50mW @ ±5V)

General Description

The SPT231 Buffer/Amplifier is a wideband operational amplifier
designed specifically for high-speed, low-gain applications. The
SPT231 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 SPT231 Buffer/Amplifier is the ideal design alternative to low
precision open-loop buffers and oscillation-prone conventional op
amps. The SPT231 offers precise gains from ±1.000 to ±5.000
and linearity that is a true 0.1%-even for demanding 50Ω 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 resistances or when the effects of
thermal tail are not included; the SPT231 Buffer/Amplifier settles
to 0.05% in 15ns-while driving a 100Ω load.

Offsets and drifts, usually a low priority in conventional high­speed op amp designs, were not ignored in the SPT231; the input
offset voltage is typically 1mV and input offset voltage drift is only
10µV/°C. The SPT231 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 compensation networks
and having to “tweak” them in production. The absence of a gain­bandwidth tradeoff in the SPT231 allows performance to be
predicted easily; the table below shows how the bandwidth is
affected very little by changing the gain setting.

The SPT231 is constructed using thin film resistor/bipolar transis­tor technology, and is available in the following versions:

SPT231AIH -25°C to +85°C 12-pin TO-8 can
SPT231AMH -55°C to +125°C 12-pin TO-8 can, features burn-

in and hermetic testing

FAST SETTLING, WIDEBAND BUFFER/AMPLIFIER (AV = ±1 to ±5)

Typical Performance

Bottom View

Package Dimensions

4755 Forge Road, Colorado Springs, Colorado 80907, USA

Phone: [phone] FAX: [phone] Website: http://www.spt.com E-Mail: [e-mail]

2 10/9/98

SPT231

Min/max ratings are based on product characterization and simulation. Individual parameters are tested as noted. Outgoing quality levels are
determined from tested parameters.

SPT231 Electrical Characteristics

(Av = +2, Vcc = ±15V, RL = 100Ω, Rf = 250Ω; unless specified)

Absolute Maximum Ratings