AD736BQ

Overview

The AD736BQ is a low power, precision, monolithic true RMS-to-DC converter manufactured by Analog Devices Inc. It converts an AC voltage waveform to a DC voltage representing the true RMS value. The device features a 200 mV rms full-scale input range and high input impedance of 10^12 Ω with maximum input bias current of 25 pA. It provides high accuracy with a maximum error of ±0.3 mV ± 0.3% of reading for sine wave inputs. The supply voltage range is +2.8 V, -3.2 V to ±16.5 V, with a maximum supply current of 200 µA.

Feature Summary

• Converts AC voltage waveforms to DC voltage representing true RMS values
• Maintains high accuracy across wide range of input waveforms including variable duty-cycle pulses
• Requires no external trims for specified accuracy
• Features buffered voltage output

Applications

• Upgrading performance of non-RMS precision rectifiers
• Measuring variable duty-cycle pulse signals
• Analyzing triac phase-controlled sine waves

Procurement Notes

Verify component authenticity through authorized Analog Devices channels or certified distributors. Confirm part status as discontinued at major retailers like DigiKey. Check datasheet revision and lot traceability. Ensure storage conditions comply with humidity sensitivity requirements. Validate pinout compatibility if replacing existing circuitry.

Selection Notes

Select this component when precise RMS conversion is required for complex waveforms beyond simple sine waves. Consider the 200 mV rms input range limitation and potential need for input attenuators for larger signals. Evaluate power consumption constraints against the 200 µA supply current specification. Verify supply voltage compatibility within the +2.8 V, -3.2 V to ±16.5 V range.

Part Context

The AD736 series represents Analog Devices' solution for accurate RMS-to-DC conversion in low-power applications. The AD736BQ variant offers laser-trimmed precision without external adjustments. It serves as a cost-effective alternative to discrete RMS circuits, providing superior accuracy for general-purpose signal processing tasks requiring true RMS measurement capabilities.

Replacement Considerations

The AD737 is a related device featuring power-down control with standby current of only 25 μA. Note that the AD737 has negative DC output voltage and 8 kΩ output impedance, differing from the AD736's buffered positive output.