Low Cost Lvdt-to-digital Converter - Analog Devices

The AD2S93 is a complete 14-bit resolution tracking LVDT-to- digital converter. A Type II tracking loop is employed to track the AB input and produce a digital output equal to (AB)/ (REF/2), where REF is a fixed amplitude ac reference phase co- herent with the AB input. This allows the measurement of any 2-, 3-, 4- and 5-wire LVDT or linear amplitude modulated in- put. The operating frequency range is from 360 Hz to 10 kHz with user definable bandwidth set externally within a range of 45 Hz to 1250 Hz. The AD2S93 has a 16-bit serial output. The MSB (LOS), read first, indicates a loss of the signal A, B, or reference inputs to the converter or transducer. The second and third MSBs are flags indicating whether [REF/2 (UNR) AB +REF/2 (OVR]) is outside the linear operating range of the converter. The dis- placement data is presented as 13-bit offset binary giving a 12- bit operating range. LOS, OVR and UNR are pinned out on the device, in addition a NULL flag is available which is set when (AB) = 0. By Analog Devices, Inc.