The AD636 is a low power monolithic IC that performs true rms-to-dc conversion on low level signals. It offers performance that is comparable or superior to that of hybrid and modular converters costing much more.
The AD636 is a low‑power true RMS‑to‑DC converter offering a 200 mV full‑scale range, 0.5 %‑1 % maximum error and a 1 MHz –3 dB bandwidth. It operates from a wide range of dual or single supplies and includes an auxiliary dB output for logarithmic RMS representation. The device is factory‑trimmed for accuracy and includes protection for input over‑voltage and short‑circuit output.
The document contains functional block diagrams, pin configurations, absolute maximum ratings, and detailed application circuits for standard, single‑supply and high‑accuracy connections. It also explains how to select the averaging time constant, trim external components for improved accuracy, and reduce output ripple with post‑filtering.
| Full‑scale input range | 200 mV |
|---|---|
| Quiescent current | 800 µA |
| Bandwidth (1 % error) | 15 MHz at 200 mV rms |
| Output current capability | up to 5 mA |
The AD636 draws a low quiescent current of about 800 µA.
The device provides a full‑scale input range of 0 mV to 200 mV rms.
The AD636 can operate from a single positive supply down to 5 V, using the biasing shown in Figure 6 and connecting the input through Pin 10.