资 源 简 介
The AD737 is a low power, precision, monolithic true rms-to-dcconverter. 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 ofinput waveforms, including variable duty cycle pulses and triac(phase) controlled sine waves. The low cost and small physicalsize of this converter make it suitable for upgrading the performanceof non-rms “precision recTIfiers” in many applicaTIons.Compared to these circuits, the AD737 offers higher accuracy atequal or lower cost.The AD737 can compute the rms value of both ac and dc inputvoltages. It can also be operated ac coupled by adding one externalcapacitor. In this mode, the AD737 can resolve input signallevels of 100 mV rms or less, despite variaTIons in temperatureor supply voltage. High accuracy is also maintained for inputwaveforms with crest factors of 1 to 3. In addiTIon, crest factorsas high as 5 can be measured (while introducing only 2.5%additional error) at the 200 mV full-scale input level.The AD737 has no output buffer amplifier, thereby significantlyreducing dc offset errors occuring at the output. This allows thedevice to be highly compatible with high input impedance A/Dconverters.
