Analog Devices' RMS-to-DC Converter Ensures Accuracy and Best-in-Class Dynamic Range

The AD8436 precision monolithic true RMS-to-DC converter features AC conversion accuracy to better than ± 0.5 percent. Uniform settling for widely variant input values enables consistent conversion rates with results displayed promptly for near-zero and high-level AC inputs. The AD8436 is immune to temperature, crest factor and supply voltage variations. Zero DC offset voltages at the converter output simplify calibration. This performance is packed into a compact 4 mm x 4 mm package integrated with a FET input and precision DC buffer amplifiers and consumes only 300 uA of power. The AD8436 is a good choice for remote, portable battery-powered instrumentation, energy and automotive applications where limited board space and outdoor environments are considerations.



Download data sheet and order samples: www.analog.com/AD8436

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Learn more with the RMS-to-DC Conversion Application Guide : http://www.analog.com/static/imported-files/design_handbooks/17505283758302176206322RMStoDC_Cover-Section-I.pdf



RMS (root mean square) is a fundamental measurement of the magnitude of an AC and DC signal and is a better measure of the power in a signal than simple averaging. RMS-to-DC converters are used in applications where precise, low power measurement of AC/DC signals is the prime objective. The AD8436 system-on-a-chip design computes the precise DC equivalent of the RMS value and provides a level of linearity and accuracy across the entire input range that enables engineers to design systems with 90 dB of dynamic range.



The AD8436 extends the crest-factor to 10 – approximately double the current industry-standard digital solution – with minimal loss of accuracy. It is particularly useful for high transit signals and can be used in designs currently using ADI’s low-power, true RMS-to-DC converters such as the AD736 and AD737 with improved performances. The device is laser trimmed and characterised at 300-mV RMS input and comes with dual and single power supplies. The AD8436 is the first RMS-to-DC converter specified to operate in the extended industrial temperature range of -40°C to 125°C. It is also available in a 0°C to 70°C temperature range version.



AD8436 Precision, Low Power, Monolithic True RMS-to-DC Converter Key Features:

Instantly computes true RMS value

Fast and constant settling time at all input levels

Wide usable dynamic range: 100 uV RMS to 3 VRMS (8.5 V p-p) full-scale

Input frequency range: 65 kHz for additional 1 percent error

Low power: 300 µA typical at ±2.4 V

Accuracy: ±10 μV ± 0.5 percent of reading max

System-on-a-chip includes FET input buffer with precision gain setting resistors, output buffer

Supply range:

Dual: +/-2.4 V to +/-18 V

Single: 4.8 V to 36 V



Availability, Pricing and Complementary Components



Product Availability Temperature Range Price Each Per 1,000 Packaging

AD8436A

Full volume production now -40˚C to 125˚C $4.95 20-lead LFCSP

4 mm x 4 mm

AD8436J

Full volume production now 0˚C to 70˚C $2.95 20-lead LFCSP

4 mm x 4 mm



Complementary components to the AD8436 in low noise, low power, precision applications include the AD7190 24-bit Sigma Delta A/D converter and the ADR3433 micropower, high accuracy voltage references