PRODUCT DESCRIPTION
The AD737 is a low power, precision, monolithic true rms-to-dc converter. It is laser trimmed to provide a maximum error of ±0.2 mV ±0.3% of reading with sine-wave inputs. Furthermore, it maintains high accuracy while measuring a wide range of input waveforms, including variable duty cycle pulses and triac (phase) controlled sine waves. The low cost and small physical size of this converter make it suitable for upgrading the performance of non-rms “precision rectifiers” in many applications. Compared to these circuits, the AD737 offers higher accuracy at equal or lower cost.

FEATURES
  COMPUTES
     True RMS Value
     Average Rectified Value
     Absolute Value
  PROVIDES
     200 mV Full-Scale Input Range (Larger Inputs with Input Attenuator)
     Direct Interfacing with 3 1/2 Digit CMOS A/D Converters
     High Input Impedance of 1012 V
     Low Input Bias Current: 25 pA max
     High Accuracy: 60.2 mV 60.3% of Reading
     RMS Conversion with Signal Crest Factors Up to 5
     Wide Power Supply Range: +2.8 V, –3.2 V to 616.5 V
     Low Power: 160 mA max Supply Current
     No External Trims Needed for Specified Accuracy
     AD736—A General Purpose, Buffered Voltage Output Version Also Available