AD698ACPZ

AD698ACPZ is a complete, monolithic Linear Variable Differential Transformer (LVDT) signal conditioning subsystem. It is used in conjunction with LVDTs to convert transducer mechanical position to a unipolar or bipolar DC voltage with a high degree of accuracy and repeatability. All circuit functions are included on the chip. With addition of a few external passive components to set frequency and gain, AD698 converts raw LVDT output to a scaled DC signal. The device operates with half-bridge LVDTs, LVDTs connected in the series opposed configuration and RVDTs. The AD698 contains a low distortion sine wave oscillator to drive LVDT primary. Two synchronous demodulation channels of the AD698 are used to detect primary and secondary amplitude. The part divides the output of the secondary by the amplitude of the primary and multiplies by a scale factor. This eliminates scale factor errors due to drift in the amplitude of the primary drive, improving temperature performance and stability.

• Single chip solution, contains internal oscillator and voltage reference
• No adjustments required
• Interfaces to half-bridge, 4-wire LVDT
• DC output proportional to position
• 20Hz to 20kHz frequency range
• Decodes AC bridge signals
• Linearity: 0.05%, output voltage: ±11V, gain drift: 20ppm/8°C (typ), offset drift: 5ppm/8°C (typ)
• Available in 40-lead LFCSP package
• Operating temperature range from –40°C to +85°C