AD736 True RMS to DC Converter IC SMD Package

The AD736 is a low-power precision True RMS-to-DC converter IC from Analog Devices, designed to accurately measure the true root mean square (RMS) value of AC signals and convert them into a proportional DC output voltage.

It can handle a wide range of input waveforms — sine, square, triangular, pulse, or complex signals with harmonics — and provides accurate RMS readings even for distorted or non-sinusoidal signals.

Housed in a compact SMD (SOIC-8) package, the AD736 is ideal for use in digital multimeters, test equipment, power monitors, and portable instruments that require high accuracy, low power, and compact design.

• The AD736 is capable of computing the average rectified value, absolute value, or true rms value of various input signals.
• Only one external component, an averaging capacitor, is required for the AD736 to perform true rms measurement.
• The low power consumption of 1 mW makes the AD736 suitable for many battery-powered applications.
• A high input impedance of 1012 ? eliminates the need for an external buffer when interfacing with input attenuators.
• A low impedance input is available for those applications that require an input signal up to 300 mV rms operating from low power supply voltages.

• Converts an ac voltage waveform to a dc voltage and then converts to the true rms, average rectified, or absolute value 200 mV rms full-scale input range (larger inputs with input attenuator)
• High input impedance: 1012 ?
• Low input bias current: 25 pA maximum
• High accuracy: ±0.3 mV ± 0.3% of reading
• RMS conversion with signal crest factors up to 5
• Wide power supply range: +2.8 V, ?3.2 V to ±16.5 V
• Low power: 200 µA maximum supply current
• Buffered voltage output
• No external trims needed for specified accuracy

Applications:

• True RMS AC voltage or current measurement
• Portable and handheld digital multimeters
• Audio level and power monitoring
• AC power and energy metering systems
• Test and calibration instruments
• Signal and waveform analysis
• Industrial process control systems

Working Principle:

The AD736 internally performs three key mathematical operations to determine the RMS value:

1. Squares the input signal.
2. Averages the squared result over time.
3. Takes the square root of the averaged value.

This process produces an output DC voltage directly proportional to the true RMS value of the input, ensuring accurate readings regardless of signal shape or distortion.