The AD737 series low power/precision monolithic true RMS-to-DC Converter maintains high accuracy while measuring a wide range of input waveforms, including variable duty cycle pulses and triac (phase) controlled sine waves. It is laser trimmed to provide a maximum error of ±0.2mV ±0.3% of reading with sine wave inputs. The 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 is higher accuracy at equal or lower cost. The AD737 computes the RMS value of both the AC and DC input voltages and is AC-coupled by adding an input capacitor. In this mode, the AD737 can resolve input signal levels of 100µVrms or less, despite variations in temperature or supply voltage. High accuracy is maintained for input waveforms with crest factors of 1 to 3 and crest factors at 2.5% or less with respect to full-scale input level.
● Computes true RMS value, average rectified value and absolute value
● Provides 200mV Full-scale input range (larger inputs with input scaling)
● Direct interfacing with 3 1/2 digit CMOS analogue-to-digital converters (ADCs)
● 1012R High input impedance
● 25pA maximum Low input bias current
● ±0.2mV ±0.3% of reading High accuracy
● RMS conversion with signal crest factors up to 5
● 25µA (typical) Standby current low power
● No external trims needed for specified accuracy
