DESCRIPTION The AD636 is a low power monolithic IC that performs true that is comparable or superior to that of hybrid and modular converters costing much more. The AD636 is specified for a signal range of 0 mV to 200 mV rms. Crest factors up to 6 can be accommodated with less than 0.5% additional error, allowing accurate measurement of complex input waveforms. The low power supply current requirement of the AD636, typically 800 A, is ideal for battery-powered portable instruments. It operates from a wide range of dual and single power supplies, from 2.5 V to 16.5 V or from +5 V to +24 V. The input and output terminals are fully protected; the input signal can exceed the power supply with no damage to the device (allowing the presence of input signals in the absence of supply voltage), and the output buffer amplifier is short-circuit protected. The AD636 includes an auxiliary dB output derived from an internal circuit point that represents the logarithm of the rms current and can be se FEATURES True rms-to-dc conversion 200 mV full scale Laser-trimmed to high accuracy 0.5% maximum error (AD636K) 1.0% maximum error (AD636J) Wide response capability Computes rms of ac and dc signals 1 MHz, 3 dB bandwidth: V rms > 100 mV Signal crest factor of 6 for 0.5% error dB output with 50 dB range Low power: 800 A quiescent current Single or dual supply operation Monolithic integrated circuit Low cost FUNCTIONAL BLOCK DIAGRAM RLdBBUF INBUF OUTIOUT10k10k+VSCAVVINCURRENTMIRRORSQUARERDIVIDERABSOLUTEVALUEAD63600787-001 Figure 1. GENERAL DESCRIPTION The AD636 is a low power monolithic IC that performs true that is comparable or superior to that of hybrid and modular converters costing much more. The AD636 is specified for a signal range of 0 mV to 200 mV rms. Crest factors up to 6 can be accommodated with less than 0.5% additional error, allowing accurate measurement of complex input waveforms. The low power supply current requirement of the AD636, typically 800 A, is ideal for battery Specifications subject to change without no