ADI AD8436ARQZ-R7

The AD8436 is a new generation precision translinear, low power, true RMS-to-DC converter monolithic system. It accurately computes the DC equivalent of the RMS value of AC waveforms, including complex waveforms from switch-mode power supplies and TRIAC-controlled sources. It delivers high accuracy conversion over a wide range of input levels and temperatures, ensuring ≤±0.5% accuracy and ≤10 μV output offset. Crest factor error is less than 0.5% for CF values between 1 and 10.

The AD8436 provides true RMS results at lower cost than peak, average, or digital solutions. With no programming cost or processor overhead to consider, the 4 mm×4 mm package easily fits space-constrained applications. The on-chip buffer amplifier provides the widest range of options without cost impact. The lowest-cost configuration requires only a single external averaging capacitor. The built-in high-impedance FET buffer provides an interface for external attenuators, frequency compensation, or driving low-impedance loads. A pair of matched internal resistors enables easy gain-of-2 or higher gain configurations, and the usable input range can be extended to lower levels. The AD8436 features a low power precision input buffer, making it ideal for portable multimeters and other battery-powered applications.

By eliminating internal bias current, the precision DC output buffer delivers extremely low offset voltage when driving low-impedance loads, minimizing errors.

Unlike digital solutions, the AD8436 performance is not limited by switching circuits at either high or low amplitudes. It responds to input signals of <100 μV and >3 V, extending dynamic range without external adjustment, accommodating demanding low-level signal conditions, and supporting a wide overrange without clamping.

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

• True RMS or average rectified value of AC waveforms
• Fast settling at any input level
• Accuracy: ±0.5% of ±10 μV reading
• Wide dynamic input range: 100 μV rms to 3 V rms (8.5 V p-p)
• Higher input with external trim of full-scale input range
• Wide bandwidth: −3 dB (300 mV) bandwidth of 1 MHz
• 7% additional error bandwidth of 65 kHz
• Zero converter DC output offset
• No residual switching artifacts
• Accurate conversion at rated 300 mV rms input, crest factor up to 10
• Low power: typical 300 μW at ±2.4 V
• High-impedance FET separately powered input buffer
• RIN ≥10¹² Ω, ΔCIN ≤2 pF
• Dual supply: ±2.4 V to ±18 V; single supply: 4.8 V to 36 V
• 4 mm×4 mm LFCSP and 3 mm×6 mm QSOP packages
• ESD protection