Low Cost Monolithic Voltage-to-Frequency Converter
The AD654 is a monolithic V/F converter consisting of an input amplifier, a precision oscillator system, and a high current output stage. A single RC network is all that is required to set up any full scale (FS) frequency up to 500 kHz and any FS input voltage up to ±30 V. Linearity error is only 0.03% for a 250 kHz FS, and operation is guaranteed over an 80 dB dynamic range. The overall temperature coefficient (excluding the effects of external components) is typically ±50 ppm/°C. The AD654 operates from a single supply of 5 V to 36 V and consumes only 2.0 mA quiescent current.
The low drift (4 µV/°C typ) input amplifier allows operation directly from small signals such as thermocouples or strain gauges while offering a high (250 M(ohm)) input resistance. Unlike most V/F converters, the AD654 provides a square-wave output, and can drive up to 12 TTL loads, optocouplers, long cables, or similar loads.
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Single-Supply Acceleration-to-Frequency Circuits
(Analog Dialogue, Vol. 29, No. 3, 1995)
Ask The Applications Engineer-3
(Analog Dialogue, 30th Anniversary Reader Bonus)
Rarely Asked Questions
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The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.