AD654JN/+

Overview

The AD654JN/+ is a monolithic voltage-to-frequency converter featuring an input amplifier, precision oscillator, and high-current output stage. It supports single or dual supplies from 5 V to 36 V with a quiescent current of 2.0 mA. The device achieves full-scale frequencies up to 500 kHz using a single RC network. Nonlinearity is specified at 0.1% for 250 kHz and 0.4% for 500 kHz. It operates over a temperature range of -40°C to +85°C in an 8-lead mini-DIP package.

Feature Summary

• Versatile input amplifier with high impedance suitable for direct connection to sensors like thermocouples.
• Open-collector output stage capable of driving TTL loads, optocouplers, and long cables.
• Requires minimal external components, utilizing only an RC timing network for frequency setup.
• Operates on a single positive supply or dual supplies with flexible logic common referencing.

Applications

• Analog-to-digital conversion using microprocessors or frequency counters.
• Isolated signal transmission via optocouplers.
• Two-wire temperature-to-frequency conversion systems.
• Phase-locked loops and tuning switched-capacitor filters.

Procurement Notes

Verify the specific suffix JN against the datasheet to confirm the 8-lead mini-DIP package and through-hole mounting style. Confirm that the part number corresponds to the standard AD654 specifications regarding supply voltage and linearity. Check for any discontinuance notices or alternative package options if availability is constrained.

Selection Notes

Select this component when a low-cost, monolithic V/F converter is required with minimal external circuitry. Ensure the application fits within the 5 V to 36 V supply range and requires frequencies up to 500 kHz. Consider the 8-lead DIP package constraints and the need for an external timing capacitor with low dielectric absorption for optimal linearity.

Part Context

The AD654 belongs to Analog Devices' family of voltage-to-frequency converters, designed for cost-effective signal conditioning. It integrates the functions of an input amplifier and oscillator into a single chip, simplifying design compared to discrete solutions. The JN suffix denotes the plastic dual in-line package variant suitable for general-purpose industrial and instrumentation applications.

Replacement Considerations

The AD654JR is a surface-mount SOIC equivalent. Verify pin compatibility and thermal characteristics when substituting packages. No other direct functional substitutes are documented in the provided source material.