AD598AD

Overview

The AD598AD is a monolithic LVDT signal conditioning subsystem manufactured by Analog Devices Inc. in a 20-lead Ceramic DIP package. It converts mechanical position to a unipolar or bipolar DC voltage with high accuracy. The device integrates a low distortion sine wave oscillator and operates on a ratiometric architecture, eliminating the need for adjustments and reducing sensitivity to phase shifts. It supports excitation frequencies from 20 Hz to 20 kHz and accepts secondary input levels as low as 100 mV rms. The AD598AD functions within a temperature range of -40°C to +85°C, drawing 15 mA at ±15 V supply.

Feature Summary

• Monolithic solution integrating oscillator and decoder for LVDT/RVDT applications
• Ratiometric decoding insensitive to null voltage and primary-to-secondary phase shifts
• Capable of driving remote LVDTs up to 300 feet and outputting signals over 1000 feet
• Thermally protected excitation output suitable for telemetry and hostile environments

Applications

• Flight control feedback systems
• Servo system position feedback
• Machine tool automatic measurement
• Proving ring weigh scales

Procurement Notes

Verify the specific suffix 'AD' confirms the ceramic DIP package and industrial temperature grade (-40°C to +85°C). Confirm that the component matches the original Analog Devices manufacturing specifications rather than third-party equivalents. Ensure the ordering information aligns with the current product lifecycle status provided by authorized distributors.

Selection Notes

Select the AD598AD when an extended operating temperature range below 0°C is required compared to the JR variant. This model is appropriate for applications demanding the robustness of a side-brazed ceramic DIP package. Verify that the external passive components selected for frequency and gain setting are compatible with the specified input voltage ranges and power supply configurations.

Part Context

The AD598AD belongs to the AD598 family of Linear Variable Differential Transformer signal conditioners. It serves as a complete subsystem for converting transducer mechanical position into a scaled DC signal. The AD variant specifically denotes the military-grade temperature performance and ceramic packaging option available alongside the standard plastic SOIC version.

Replacement Considerations

The AD598JR is the pin-compatible alternative offering a lower temperature range (0°C to +70°C) in a plastic SOIC package. For military specifications, the AD598SD/883B processed to MIL-STD-883B covers the -55°C to +125°C range.