Precision voltage-to-frequency converters

Onlinecomponents.com, an authorized distributor of Texas Instrument, features the LM231/LM331 family. The devices are voltage-to-frequency converters that are suited ideally for use in simple low-cost circuits for analog-to-digital conversion, long term integration, linear frequency 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 advantages of the voltage-to-frequency conversion techniques, and is easy to apply in all standard voltage-to-frequency converter applications. Further, the LM231A/LM331A attain a new high level of accuracy versus temperature which could only be attained with expensive voltage-to-frequency modules. Additionally the LM231/331 are ideally suited for use in digital systems at low power supply 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/LM331utilize a new temperature-compensated band-gap reference circuit, to provide excellent accuracy over the full operating temperature range, at power supplies as low as 4.0 V. The precision timer circuit has low bias currents without degrading the quick response necessary for 100kHz voltage-to-frequency conversion. And the output are capable of driving 3 TTL loads, or a high voltage output up to 40 V, yet is short-circuit-proof against VCC.