AD737AR

Overview

The AD737AR is a low power, precision, monolithic true RMS-to-DC converter manufactured by Analog Devices Inc. It is laser trimmed to provide a maximum error of ±0.2 mV plus 0.3% of reading with sine wave inputs. The device maintains high accuracy while measuring a wide range of input waveforms, including variable duty cycle pulses and triac phase-controlled sine waves. It features a 200 mV full-scale input range, direct interfacing with 3½ digit CMOS ADCs, and a high input impedance of 10^12 Ω. The part operates on a wide power supply range from ±2.5 V to ±16.5 V with a typical standby current of 25 µA.

Feature Summary

• Computes true RMS value for accurate signal measurement across various waveform types
• Provides average rectified value and absolute value outputs
• Features high input impedance and low input bias current for minimal signal loading
• Requires no external trims for specified accuracy

Applications

• Upgrading performance of non-RMS precision rectifiers
• Direct interfacing with 3½ digit CMOS ADCs
• Measurement of variable duty cycle pulses
• Analysis of triac phase-controlled sine waves

Procurement Notes

Verify the specific suffix 'AR' against the official Analog Devices datasheet to confirm package type and temperature rating. Ensure compatibility with system voltage rails within the ±2.5 V to ±16.5 V range. Confirm that the negative-going output polarity aligns with downstream circuit requirements. Check for RoHS compliance status in the latest documentation.

Selection Notes

Select this component when precise RMS conversion is required for complex waveforms beyond simple sine waves. Consider the negative output polarity and ensure appropriate signal conditioning if positive output is needed. Evaluate the 200 mV full-scale range against input signal levels to determine if scaling is necessary. Compare power consumption requirements against the 25 µA standby current specification.

Part Context

The AD737 series includes the AD736, which provides a positive output-going version of the same basic device. Both parts are designed for low-cost, low-power applications requiring true RMS conversion. The AD737AR variant specifically denotes the industrial temperature range and SOIC package configuration as per Analog Devices naming conventions.

Replacement Considerations

The AD736 serves as a functional alternative with positive output polarity. Verify pinout compatibility and output polarity requirements before substitution. No other direct substitutes are confirmed in public documentation.