Analog Devices Inc. AD8436BRQZ-RL

Overview

AD8436BRQZ-RL from Analog Devices is a precision true RMS-to-DC converter IC designed for accurate ac signal measurement in instrumentation and power monitoring systems. It delivers ±10 μV ±0.25% reading accuracy (B grade), supports 100 μV_rms to 3 V_rms full-scale input, operates from ±2.4 V to ±18 V dual supplies, and features integrated FET input and precision DC output buffers.

For engineers reviewing the AD8436BRQZ-RL datasheet, AD8436BRQZ-RL pinout, AD8436BRQZ-RL application, or AD8436BRQZ-RL equivalent, key selection criteria include crest factor error <0.5% (CF = 1–10), 65 kHz bandwidth at 1% error, low 300 µA supply current, 10¹² Ω input resistance, and compatibility with single-supply (4.8 V–36 V) or dual-supply operation.

Technical Context

The AD8436BRQZ-RL implements a translinear RMS core using voltage-to-current conversion, absolute value circuitry, and log-antilog transistor arrays for squaring and square-rooting - enabling true RMS computation without digital processing. Its architecture eliminates switching artifacts and supports continuous dc-equivalent output down to 100 μV_rms.

It integrates two independent, separately powered amplifiers: a high-Z JFET input buffer (R_IN ≥ 10¹² Ω, C_IN ≤ 2 pF) and a laser-trimmed bipolar output buffer with <150 μV offset (B grade). Both buffers can be disabled to reduce power consumption, and internal 10 kΩ matched resistors support configurable gain.

Key Specifications

Pinout & Package

The AD8436BRQZ-RL is housed in a 20-lead QSOP package (RQ-20), with exposed pad optional for thermal enhancement. Pin functions are electrically validated per Analog Devices Rev. E datasheet Figure 4 and Table 4.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar true RMS-to-DC conversion applications.

Compared with AD737JRZ-REEL and LTC1966CMS8#TRPBF, the AD8436BRQZ-RL uniquely combines ultra-low power (300 µA), 10¹² Ω input impedance, and <0.5% crest factor error - making it the only option suitable for battery-powered, high-fidelity RMS measurement across 100 μV–3 V_rms without external active components.

Availability

AD8436BRQZ-RL is available at Aetrix Electronics and suitable for energy metering, portable multimeters, industrial motor monitoring, and power supply diagnostics requiring stable component supply and long-term manufacturability.

Supply support for AD8436BRQZ-RL includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Wilmington, MA.

The AD8436 belongs to Analog Devices' precision signal conditioning product line, engineered specifically for high-accuracy, low-power true RMS measurement in portable, industrial, and energy infrastructure applications.

FAQ

What is the guaranteed accuracy specification for AD8436BRQZ-RL?

The AD8436BRQZ-RL (B grade) guarantees ±10 μV ±0.25% of reading accuracy under default conditions (e_IN = 300 mV_rms, 1 kHz sine, ±5 V supplies, 25°C). This includes both offset and gain error contributions, and is specified with AC-coupled input to eliminate DC offset effects. The AD8436BRQZ-RL maintains this accuracy across its full −40°C to +125°C operating temperature range with a drift of only 0.3 μV/°C on output offset.

Can AD8436BRQZ-RL operate from a single supply?

Yes, the AD8436BRQZ-RL supports single-supply operation from 4.8 V to 36 V. Internal biasing allows the IGND pin to serve as a half-supply reference, enabling rail-to-rail input and output swing when configured appropriately. The AD8436BRQZ-RL datasheet provides verified test circuits (Figure 22) and layout guidance for stable single-supply use, including decoupling and capacitor selection for CAVG and CCF.

How does the AD8436BRQZ-RL handle non-sinusoidal waveforms?

AD8436BRQZ-RL delivers true RMS conversion for arbitrary waveforms, with crest factor error <0.5% for CF values between 1 and 10. This is validated for complex signals including triac-dimmed lighting, switched-mode power supply outputs, and motor drive currents. Unlike averaging or peak-detecting converters, the AD8436BRQZ-RL's translinear core computes the exact heating value regardless of harmonic content - confirmed by Table 5 in the AD8436BRQZ-RL datasheet.

What external components are required for basic AD8436BRQZ-RL operation?

A single 10 μF capacitor on the CAVG pin is sufficient for basic AD8436BRQZ-RL operation at frequencies down to 40 Hz. Optional components include a 0.1 μF crest factor capacitor (CCF), external gain-setting resistors (if using IBUFGN), and decoupling capacitors on VCC/VEE and buffer supply pins. No external op-amps, ADCs, or microcontrollers are needed - the AD8436BRQZ-RL delivers fully conditioned DC output directly.

Is the AD8436BRQZ-RL pin-compatible with other members of the AD8436 family?

Yes, the AD8436BRQZ-RL shares identical pinout and footprint with all AD8436 variants in the RQ-20 QSOP package, including AD8436ARQZ and AD8436JRQZ. Differences are limited to grade-specific parameters (accuracy, temperature range, offset) - not electrical connectivity or layout. The AD8436BRQZ-RL may be substituted on existing boards designed for other RQ-20 AD8436 versions without PCB modification.