Analog Devices Inc. AD8436BCPZ-WP

Overview

AD8436BCPZ-WP from Analog Devices is a translinear precision true RMS-to-DC converter IC used for accurate ac waveform measurement in signal conditioning and power monitoring circuits. It delivers ±10 μV ±0.25% reading accuracy (B grade), supports 100 μV–3 V rms input range, operates from ±2.4 V to ±18 V dual supply, and features integrated FET input and precision DC output buffers. It is deployed in portable multimeters and industrial energy meters.

For engineers reviewing the AD8436BCPZ-WP datasheet, AD8436BCPZ-WP pinout, AD8436BCPZ-WP application, or AD8436BCPZ-WP equivalent, key selection considerations include crest factor error <0.5% (CF=1–10), 65 kHz bandwidth for 1% additional error, 1 MHz −3 dB bandwidth at 300 mV, low 300 µA typical supply current, and compatibility with 4 mm × 4 mm LFCSP packaging.

Technical Context

The AD8436BCPZ-WP implements an implicit-function translinear architecture using bipolar junction transistor log-antilog arrays for squaring and square-rooting, enabling true RMS computation without digital processing. Its RMS core accepts current-mode input via an 8 kΩ precision V-to-I resistor and outputs either voltage (via internal 16 kΩ I-to-V resistor) or current (by floating OGND).

The device 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 support optional disconnection to reduce system power consumption.

Key Specifications

Pinout & Package

AD8436BCPZ-WP is housed in a 4 mm × 4 mm, 20-lead LFCSP (CP-20-8) package with exposed thermal pad (optional ground connection). Pin functions are validated per Analog Devices Rev. E datasheet Figure 3 and Table 3.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD736JRZ and LTC1966CMS8#PBF, AD8436BCPZ-WP uniquely balances ultra-low power (300 µA), wide supply flexibility (±2.4 V to ±18 V), integrated FET buffer with independent power control, and guaranteed <0.5% crest factor error-making it optimal for portable, wide-dynamic-range, and industrial-grade RMS measurement.

Availability

AD8436BCPZ-WP is available at Aetrix Electronics and suitable for energy metering, portable multimeters, industrial process monitoring, and power quality analyzers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for AD8436BCPZ-WP 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 Norwood, MA.

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

FAQ

What is the guaranteed accuracy specification for AD8436BCPZ-WP over temperature?

The AD8436BCPZ-WP guarantees ±10 μV ±0.25% of reading accuracy (B grade) at 25°C, with temperature coefficient of 0.3 μV/°C for output offset and 0.006%/°C for conversion error across −40°C to +125°C. These values are confirmed in Table 1 of the Rev. E datasheet under "Vs. Temperature" test conditions, and apply directly to the AD8436BCPZ-WP's LFCSP package variant.

Can AD8436BCPZ-WP operate from a single 5 V supply?

Yes, AD8436BCPZ-WP supports single-supply operation from 4.8 V to 36 V. When using +5 V, VEE must be connected to ground, IGND serves as the internal mid-rail reference (~2.5 V), and ac-coupled inputs ensure zero output offset. The Rev. E datasheet Figure 22 shows a verified single-supply test circuit with 4.80 V supply and proper decoupling.

How does the CCF capacitor improve performance in AD8436BCPZ-WP?

The CCF capacitor (pin 18) reduces crest factor error to <0.5% for waveforms with crest factors from 1 to 10 when a 0.1 µF capacitor is used. This is validated in Figure 14 of the AD8436BCPZ-WP datasheet, which plots additional error vs. crest factor for CAVG = 10 µF and CCF = 0.1 µF. Without CCF, crest factor error increases significantly above CF = 3.

Is the FET input buffer in AD8436BCPZ-WP mandatory, or can it be bypassed?

The FET input buffer in AD8436BCPZ-WP is optional and can be bypassed. To bypass, connect IBUFIN+ directly to RMS (pin 2) and leave IBUFV+ unconnected. This disables the buffer, saving ~160 µA supply current. The RMS core's 8 kΩ input impedance remains active, as confirmed in Table 1 (Input Resistance = 7.92–8.08 kΩ).

What is the minimum recommended CAVG value for 50 Hz RMS measurement with ≤0.1% error using AD8436BCPZ-WP?

For 50 Hz input and ≤0.1% RMS error, the AD8436BCPZ-WP requires a minimum CAVG of 47 µF, as determined from Figure 28 in the Rev. E datasheet. At 50 Hz, the intersection of 0.1% error and 50 Hz falls between the 22 µF and 100 µF curves; selecting 47 µF ensures margin while minimizing size and cost versus 100 µF.