ADI AD598JRZ

The AD598 is a complete monolithic linear variable differential transformer (LVDT) signal conditioning subsystem. Used in conjunction with an LVDT, it converts the mechanical position of the sensor into a DC voltage with high accuracy and repeatability. All circuit functions are integrated on the chip. By adding a few external passive components to set the frequency and gain, the AD598 can convert the raw LVDT secondary outputs into a scaled DC signal. The device can also be used with RVDT sensors. The AD598 contains a low-distortion sine wave oscillator to drive the LVDT primary. The LVDT secondary outputs consist of two sine waves that directly drive the AD598. The AD598 processes these two signals, dividing their difference by their sum to produce a scaled, single- or bipolar DC output. The AD598 uses a unique ratiometric architecture (patent pending) that eliminates some of the drawbacks of traditional LVDT interface methods. Benefits of this new circuit include: no trimming required, transformer null voltage and primary-to-secondary phase shift do not affect system accuracy, improved temperature stability, and better sensor interchangeability.

• For use with LVDT and RVDT, converting mechanical position to DC voltage
• Capable of driving remote LVDT up to 300 feet away
• Position output capable of driving cables up to 1000 feet
• Suitable for telemetry applications or harsh environments
• Usable as a loop integrator in simple electromechanical servo loops