AD637JD

The AD637JD by Analog Devices is a high-precision, wideband RMS-to-DC converter designed to compute the true RMS value of any complex waveform. It offers exceptional accuracy with a maximum nonlinearity of 0.02% for inputs from 0 V to 2 V rms. The 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 supports crest factors up to 10 with less than 1% additional error.

This IC computes true RMS, mean square, or absolute value, providing an equivalent DC output voltage. A dedicated pin offers a direct dB output with a 60 dB range. The AD637JD features a chip select/power-down function, reducing quiescent current from 2.2 mA to 350 µA when not in use, making it suitable for low-power applications. It is housed in a 14-CDIP package and supports through-hole mounting.

The device is laser wafer trimmed for rated performance without external adjustments, requiring only an external capacitor to set the averaging period. The on-chip buffer amplifier can be configured as an input buffer or an active filter to reduce ripple and increase accuracy. The AD637JD is designed for applications requiring precise RMS measurements of AC or AC plus DC signals.