Vishay ISO-AC-VSAO Reference Design

Vishay ISO-AC-VSAO Reference Design focuses on voltage-sensing solutions for high AC-voltage applications that require an isolated high-voltage sensing circuit. This application is based on the Vishay VIA0250DD isolation amplifier and a voltage divider comprising a set of TNPV resistors. The high voltage input (UACIN to REF) is scaled down to UAC to REF using a set of TNPV resistors. This reduced voltage is then fed into the VIA0250DD isolation amplifier, producing an isolated, amplified analog signal at its output (OUTP to OUTN).

The differential output signal, with a common-mode voltage of 1.44V, is accessible via pin headers labeled OUTP and OUTN, allowing users to connect a differential ADC or use it for other prototyping needs. This differential output is converted to a single-ended output, providing a range of 0V to 2.5V (OUT to GND), ready for interfacing with a single-ended ADC or multimeter. To minimize thermal drift, the differential-to-single-ended conversion stage uses the ACAS resistor network, providing well-matched resistance values over a wide temperature range.