Features: · Guaranteed linearity 0.01% max
· Improved performance in existing voltage-to-frequency conversion applications
· Split or single supply operation
· Operates on single 5V supply
· Pulse output compatible with all logic forms
· Excellent temperature stability, g50 ppm/§C max
· Low power dissipation, 15 mW typical at 5V
· Wide dynamic range, 100 dB min at 10 kHz full scale frequency
· Wide range of full scale frequency, 1 Hz to 100 kHz
· Low cost
Application*Use stable components with low temperature coefficients. See Typical Applications section.
**0.1mFor1mF, See ''Principles of Operation.''SpecificationsIf Military/Aerospace specified devices are required, please contact the National Semiconductor Sales ffice/Distributors for availability and specifications.
LM131A/LM131 LM231A/LM231 LM331A/LM331
Supply Voltage 40V 40V 40V
Output Short Circuit to Ground Continuous Continuous Continuous
Output Short Circuit to VCC Continuous Continuous Continuous
Input Voltage -0.2V to aVS -0.2V to aVS -0.2V to aVS
TMIN TMAX TMIN TMAX TMIN TMAX
Operating Ambient Temperature Range -55to +125 -25to +85 0to +70
Power Dissipation (PD at 25)
and Thermal Resistance (jA)
(H Package) PD 670 mW
jA 150/W
(N Package) PD 1.25W 1.25W
jA 100/W 100/W
(M Package)PD 1.25W
JA 85/W
Lead Temperature (Soldering, 10 sec.)
Dual-In-Line Package (Plastic) 260 260 260
Metal Can Package (TO-5) 260
ESD Susceptibility (Note 4)
Metal Can Package (TO-5) 2000V
Other Packages 500V 500VDescriptionThe LM331_1240109 family of voltage-to-frequency converters are ideally suited for use in simple low-cost cir-cuits for analog-to-digital conversion, precision frequency-to-voltage conversion, long-term integration, linear frequen-cy modulation or demodulation, and many other functions.The output when used as a voltage-to-frequency converter is a pulse train at a frequency precisely proportional to the applied input voltage. Thus, it provides all the inherent ad-vantages of the voltage-to-frequency conversion tech-niques, and is easy to apply in all standard voltage-to-fre-quency converter applications. Further, the LM331_1240109 attains a new high level of accuracy ver-sus temperature which could only be attained with expen-sive voltage-to-frequency modules. Additionally the LM131 is ideally suited for use in digital systems at low power sup-ply voltages and can provide low-cost analog-to-digital con-version in microprocessor-controlled systems. And, the fre-quency from a battery powered voltage-to-frequency con-verter can be easily channeled through a simple photoisola-tor to provide isolation against high common mode levels.The LM331_1240109 utilizes a new temperature-compensated band-gap reference circuit, to provide excel-lent 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 is capable of driving 3 TTL loads, or a high voltage output up to 40V, yet is short-circuit-proof against VCC.
LM331_1240109 Data Sheet
