**The AD736AQ: A Precision Low-Level True RMS Converter for Demanding Measurement Applications**

In the realm of electronic measurement, accurately quantifying the magnitude of complex, real-world signals is a fundamental challenge. While average-responding meters are sufficient for pure sinusoidal waveforms, they fail dramatically when faced with the distorted, non-sinusoidal signals common in modern systems—from variable-speed motor drives to audio equipment and switching power supplies. For these demanding applications, a True Root Mean Square (RMS) measurement is essential, as it directly correlates to the power content of a signal regardless of its waveshape. The **AD736AQ** stands as a premier solution in this domain, a monolithic integrated circuit specifically engineered to deliver **high-precision, low-level true RMS conversion**.

The core innovation of the AD736AQ lies in its ability to compute the true RMS value of an AC signal. The mathematical definition of RMS is the square root of the mean of the square of the input signal over a specified period (√(1/T ∫₀ᵀ v²(t) dt)). The AD736AQ performs this computation directly through a sophisticated internal architecture. It employs an **implicit computation technique** using a proprietary translinear core, which squares, averages, and then takes the square root of the input signal. This method provides a significant advantage over earlier RMS converters that required external components for the averaging function, offering greater accuracy, stability, and simplicity of design.

A key feature that distinguishes the AD736AQ in precision applications is its exceptional performance with **low-level input signals**. It can accurately measure AC signals with amplitudes as low as **100 μV rms** and up to 200 mV rms full-scale, making it indispensable for sensitive measurements where signal levels are minute. Furthermore, it boasts a wide bandwidth of 370 kHz (guaranteed for 100 mV rms inputs) and maintains high accuracy even for signals with high crest factors up to 5. This capability ensures that the peaks of complex waveforms, such as pulse trains or audio signals, are measured correctly without overloading the converter or introducing significant errors.

The versatility of the AD736AQ is another hallmark. It offers two output options: a filtered DC output equivalent to the RMS value and a buffered AC output of the squared function, providing flexibility for system designers. Its high input impedance (1012 Ω) minimizes loading on the signal source, and its laser-trimmed precision ensures a low total error budget, typically less than ±0.3% of reading for many common waveforms. Housed in a robust 8-pin cerdip package, the "AQ" grade is specified over the full military temperature range (-55°C to +125°C), underscoring its reliability in the most severe environments, from aerospace and defense to industrial automation.

In practical terms, the AD736AQ finds its place in a vast array of critical measurement instruments. It is the cornerstone of **high-accuracy digital multimeters (DMMs)**, power analyzers, and panel meters. It is also deployed in vibration analysis systems, audio power measurement, and any scenario where the true power of a non-sinusoidal signal must be known for design validation, quality control, or system monitoring.

**ICGOODFIND:** The AD736AQ remains a benchmark in analog computation, providing an unparalleled combination of **accuracy, bandwidth, and versatility for true RMS measurement**. Its ability to handle low-level signals with high precision and its robust performance across extreme temperatures make it an enduringly relevant component for the most demanding measurement challenges in engineering.

**Keywords:** True RMS Converter, Low-Level Signal Measurement, High Precision, Crest Factor, Implicit Computation.