LM231, LM331

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SNOSBI2B – JUNE 1999 – REVISED MARCH 2013

LM231A/LM231/LM331A/LM331 Precision Voltage-to-Frequency Converters

Check for Samples: LM231, LM331

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FEATURES

DESCRIPTION

The LM231/LM331 family of voltage-to-frequency

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•

Ensured Linearity 0.01% max

converters are ideally suited for use in simple low-

•

Improved Performance in Existing Voltage-to-

cost circuits for analog-to-digital conversion, precision

Frequency Conversion Applications

frequency-to-voltage

conversion,

long-term

•

Split or Single Supply Operation

integration,

linear

frequency

modulation

or

demodulation, and many other functions. The output

•

Operates on Single 5V Supply

when used as a voltage-to-frequency converter is a

•

Pulse Output Compatible with All Logic Forms

pulse train at a frequency precisely proportional to the

•

Excellent Temperature Stability: ±50 ppm/°C

applied input voltage. Thus, it provides all the

max

inherent

advantages

of

the

voltage-to-frequency

conversion techniques, and is easy to apply in all

•

Low Power Consumption: 15 mW Typical at 5V

standard voltage-to-frequency converter applications.

•

Wide Dynamic Range, 100 dB min at 10 kHz

Further, the LM231A/LM331A attain a new high level

Full Scale Frequency

of accuracy versus temperature which could only be

•

Wide Range of Full Scale Frequency: 1 Hz to

attained

with

expensive

voltage-to-frequency

modules. Additionally the LM231/331 are ideally

100 kHz

suited for use in digital systems at low power supply

•

Low Cost

voltages and can provide low-cost analog-to-digital

conversion

in

microprocessor-controlled

systems.

And, the frequency from a battery powered voltage-

to-frequency converter can be easily channeled

through a simple photo isolator to provide isolation

against high common mode levels.

The

LM231/LM331

utilize

a

new

temperature-

compensated band-gap reference circuit, to provide

excellent accuracy over the full operating temperature

range, at power supplies as low as 4.0V. The

precision timer circuit has low bias currents without

degrading the quick response necessary for 100 kHz

voltage-to-frequency conversion. And the output are

capable of driving 3 TTL loads, or a high voltage

output up to 40V, yet is short-circuit-proof against

CONNECTION DIAGRAM

Figure 1. Plastic Dual-In-Line Package (PDIP)

See Package Number P (R-PDIP-T8)

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PRODUCTION DATA information is current as of publication date.

Copyright © 1999–2013, Texas Instruments Incorporated

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.