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An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. PRODUCTION DATA.

LF298-MIL

SNOSD57 – JUNE 2017

LF298-MIL Monolithic Sample-and-Hold Circuits

1

1 Features

1

•

Operates from ±5-V to ±18-V Supplies

•

Less than 10-μs Acquisition Time

•

Logic Input Compatible With TTL, PMOS, CMOS

•

0.5-mV Typical Hold Step at Ch = 0.01 µF

•

Low Input Offset

•

0.002% Gain Accuracy

•

Low Output Noise in Hold Mode

•

Input Characteristics Do Not Change During Hold

Mode

•

High Supply Rejection Ratio in Sample or Hold

•

Wide Bandwidth

•

Space Qualified, JM38510

2 Applications

•

Ramp Generators With Variable Reset Level

•

Integrators With Programmable Reset Level

•

Synchronous Correlators

•

2-Channel Switches

•

DC and AC Zeroing

•

Staircase Generators

3 Description

The LF298-MIL devices are monolithic sample-and-

hold circuits that use BI-FET technology to obtain

ultrahigh DC accuracy with fast acquisition of signal

and low droop rate. Operating as a unity-gain

follower, DC gain accuracy is 0.002% typical and

acquisition time is as low as 6 µs to 0.01%. A bipolar

input stage is used to achieve low offset voltage and

wide bandwidth. Input offset adjust is accomplished

with a single pin and does not degrade input offset

drift. The wide bandwidth allows the LF298-MIL to be

included

inside

the

feedback

loop

of

1-MHz

operational

amplifiers

without

having

stability

source impedances to be used without degrading

accuracy.

P-channel junction FETs are combined with bipolar

devices in the output amplifier to give droop rates as

low as 5 mV/min with a 1-µF hold capacitor. The

JFETs have much lower noise than MOS devices

used in previous designs and do not exhibit high

temperature instabilities. The overall design ensures

no feedthrough from input to output in the hold mode,

even for input signals equal to the supply voltages.

Logic inputs on the LF298-MIL are fully differential

with low input current, allowing for direct connection

to TTL, PMOS, and CMOS. Differential threshold is

1.4 V. The LF298-MIL will operate from ±5-V to ±18-V

supplies.

An A version is available with tightened electrical

specifications.

Device Information(1)

PART NUMBER

PACKAGE

BODY SIZE (NOM)

LF298-MIL

SOIC (14)

8.65 mm × 3.91 mm

TO-99 (8)

9.08 mm × 9.08 mm

(1) For all available packages, see the orderable addendum at

the end of the data sheet.

Typical Connection

Acquisition Time