AD637JR

The AD637JR by Analog Devices is a high-precision, wideband RMS-to-DC converter designed to compute the true RMS value of complex AC or AC plus DC input waveforms. It offers exceptional accuracy with a maximum nonlinearity of 0.02% for inputs from 0 V to 2 V rms.

This converter boasts a wide bandwidth, operating at 8 MHz for inputs above 1 V rms and 600 kHz for inputs as low as 100 mV rms. It provides superior crest factor compensation, allowing measurements of signals with crest factors up to 10 with less than 1% additional error. The AD637JR can compute true RMS, mean square, or absolute value, outputting an equivalent DC voltage. A dedicated pin provides a direct dB output with a 60 dB range.

Designed for ease of use, the AD637JR requires only an external capacitor to set the averaging period. It features a chip select/power-down function that reduces quiescent current from 2.2 mA to 350 µA, making it suitable for power-sensitive applications. When powered down, the output enters a high-impedance state, enabling multiple AD637JR devices to form a wideband true RMS multiplexer.

The AD637JR is available in a 16-SOIC Surface Mount package. Its input circuitry is protected against overload voltages exceeding supply levels, and the inputs are not damaged if supply voltages are lost. This component is laser wafer trimmed for rated performance without external adjustments.