The 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, Inc., 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.
|Title||Content Type||File Type|
|AD8436: Low Cost, Low Power, True RMS-to-DC Converter Data Sheet (Rev B, 01/2013) (pdf, 193 kB)||Data Sheets|
AD8436: Low Cost, Low Power, True RMS-to-DC Converter
Consider the AD8436 as an rms-dc toolbox. It is a highly integrated compact device that meets the demands of the 21st century, delivering modern solutions to industrial and instrumentation problems.
RMS-to-DC Application Guide Second Edition
|Introduction to Analog RMS-to-DC Technology: Converters and Applications||Online Training Modules||HTML|
|MS-2405: Simple Circuit Measures the RMS Value of an AC Power Line (pdf, 234 kB)||Technical Articles|
|Analog Devices' RMS-to-DC Converter Ensures Accuracy and Best-in-Class Dynamic Range (15 Aug 2011)||Press Releases||HTML|
|What is rms?||FAQs/RAQs||HTML|
|What does rms mean in the context of electrical engineering?||FAQs/RAQs||HTML|
|What then is an rms-dc converter?||FAQs/RAQs||HTML|
|Why is rms important?||FAQs/RAQs||HTML|
|What does 'true rms' mean?||FAQs/RAQs||HTML|
|What is unique about the AD8436?||FAQs/RAQs||HTML|
|What about power consumption for the added amplifiers?||FAQs/RAQs||HTML|
|My hand-held meter project has only a battery for a power supply. Must I provide a separate negative power supply for the AD8436?||FAQs/RAQs||HTML|
|You advertise conversion down to 100μV. Why would anyone need this type of level?||FAQs/RAQs||HTML|
|So far you've spoken only about power applications. What other types of applications would the AD8436 fulfill?||FAQs/RAQs||HTML|
|Glossary of EE Terms||Glossary||HTML|
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|AD8436 SPICE Macro Model||SPICE Models||HTML|
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.