AD8436 RMS-to-DC Converter

Low cost, low power, true RMS-to-DC converters

Image of Analog Devices' AD8436 RMS-to-DC ConverterAnalog Devices' AD8436 is a new generation, translinear precision, low power, true RMS-to-DC converter loaded with options. It computes a precise DC equivalent of the RMS value of AC wave-forms, including complex patterns such as those generated by switch mode power supplies and TRIACs. Its accuracy spans a wide range of input levels (see Figure 2) and temperatures. The ensured accuracy of ≤±0.5% and ≤10 μV output offset result from the latest Analog Devices technology. The crest factor error is <0.5% for CF values between 1 and 10.

The AD8436 delivers true RMS results at less cost than misleading peak, averaging, or digital solutions. There is no programming expense or processor overhead to consider, and the 4 mm × 4 mm package easily fits into tight applications. On-board buffer amplifiers enable the widest range of options for any RMS-to-DC converter available, regardless of cost. For minimal applications, only a single external averaging capacitor is required. The built-in high impedance FET buffer provides an interface for external attenuators, frequency compensation, or driving low impedance loads. A matched pair of internal resistors enables an easily configurable gain-of-two or more, extending the usable input range even lower. The low power, precision input buffer makes the AD8436 attractive for use in portable multi-meters and other battery-powered applications.

The precision DC output buffer minimizes errors when driving low impedance loads with extremely low offset voltages, thanks to internal bias current cancellation. Unlike digital solutions, the AD8436 has no switching circuitry limiting performance at high or low amplitudes (see Figure 2). A usable response of <100 μV, and >3 V extends the dynamic range with no external scaling, accommodating demanding low level signal conditions and allowing ample overrange without clipping.

The AD8436 operates from single or dual supplies of ±2.4 V (4.8 V) to ±18 V (36 V). A and J grades are available in a compact 4 mm × 4 mm, 20-lead chip-scale package; A and B grades are available in a 20-lead QSOP package. The operating temperature ranges are −40°C to 125°C for A and B grades and 0°C to 70°C for J grade.


ImageManufacturer Part NumberDescriptionPackagingPart StatusCurrent - SupplyAvailable QuantityView Details
AD8436ACPZ-R7 datasheet linkIC CONV TRUE RMS-DC LP 20LFCSPAD8436ACPZ-R7IC CONV TRUE RMS-DC LP 20LFCSPCut Tape (CT)Active325µA4067 - Immediate
AD8436ACPZ-R7 product page link
AD8436-EVALZ datasheet linkBOARD EVAL FOR AD8436AD8436-EVALZBOARD EVAL FOR AD8436ActiveInterface, RMS to DC Converters-5 - Immediate
39 - Factory Stock
AD8436-EVALZ product page link
AD8436ARQZ datasheet linkIC CONV TRUE RMS-DC LP 20QSOPAD8436ARQZIC CONV TRUE RMS-DC LP 20QSOPTubeActive325µA0AD8436ARQZ product page link
AD8436JCPZ-WP datasheet linkIC CONV TRUE RMS-DC LP 20LFCSPAD8436JCPZ-WPIC CONV TRUE RMS-DC LP 20LFCSPTray - WaffleActive325µA0AD8436JCPZ-WP product page link
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Published: 2013-04-03