Analog Devices Inc. AD8218BCPZ-RL

Overview

AD8218BCPZ-RL from Analog Devices is a zero-drift, bidirectional current shunt monitor IC designed for high-side sensing in 4 V to 80 V systems. It delivers 20 V/V fixed gain, ±50 µV typical input offset, ±100 nV/°C offset drift, and 110 dB CMRR at dc - enabling precision current measurement across shunt resistors in telecom power supplies and motor control circuits.

For engineers reviewing the AD8218BCPZ-RL datasheet, AD8218BCPZ-RL pinout, AD8218BCPZ-RL application, or AD8218BCPZ-RL equivalent, key selection criteria include its 80 V common-mode range, internal 80 mV reference enablement via ENB pin, LFCSP package thermal performance, and differential input voltage limit of 250 mV for accurate amplification.

Technical Context

The AD8218BCPZ-RL implements a zero-drift difference amplifier core with matched 1.5 MΩ/75 kΩ resistor network (0.01% matching), yielding a precise 20 V/V gain. Its internal LDO allows VS pin floating when powered from +IN, supporting operation directly from 4 V–80 V common-mode rails.

Bidirectional sensing is enabled by applying an external low-impedance reference voltage to the REF pin (1 V/V gain), while unidirectional mode uses the internal 80 mV reference activated by grounding ENB. Output clamping limits swing to 0.01 V to VS − 0.1 V, protecting downstream ADCs.

Key Specifications

Pinout & Package

The AD8218BCPZ-RL is housed in an 8-lead LFCSP_WD (CP-8-4) package with exposed pad connected to GND, optimized for thermal dissipation in high-power current sensing applications.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar current shunt monitor applications.

Compared with MAX40056ATA+T and INA240A1QDRQ1, the AD8218BCPZ-RL uniquely integrates an enableable 80 mV reference and LFCSP thermal efficiency, making it optimal for compact, high-temperature telecom and motor control designs where internal reference simplifies layout and exposed-pad cooling is critical.

Availability

AD8218BCPZ-RL is available at Aetrix Electronics and suitable for 48 V telecom power monitoring, bidirectional motor control, base station power amplifier bias, and precision high-voltage current sources requiring stable component supply across extended temperature and high common-mode conditions.

Supply support for AD8218BCPZ-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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, communications, and automotive markets since 1965.

The AD8218BCPZ-RL belongs to Analog Devices' precision current sense amplifier product line, engineered specifically for high-voltage, high-accuracy shunt-based current measurement in harsh thermal and electrical environments.

FAQ

What is the maximum common-mode voltage the AD8218BCPZ-RL can withstand continuously?

The AD8218BCPZ-RL operates continuously from 4 V to 80 V common-mode input voltage. Its absolute maximum rating allows survival up to +85 V on +IN/−IN pins, but functional operation is specified only within the 4 V–80 V range. This makes the AD8218BCPZ-RL suitable for 48 V telecom systems and industrial 24–72 V rails without external attenuation.

How does the ENB pin affect the transfer function of the AD8218BCPZ-RL?

When ENB is grounded, the AD8218BCPZ-RL enables its internal 80 mV reference, shifting the output transfer function to OUT = (20 × VIN) + 0.08 V. This sets the zero-current output to 80 mV, maximizing ADC dynamic range in unidirectional applications. Leaving ENB open disables the reference, reverting to OUT = (20 × VIN) + VREF, where VREF is externally applied to Pin 7.

Can the AD8218BCPZ-RL be used for bidirectional current sensing without an external reference voltage?

No - bidirectional operation of the AD8218BCPZ-RL requires an external low-impedance reference voltage applied to the REF pin (Pin 7). The device provides 1 V/V gain from REF to OUT, allowing users to set the output midpoint (e.g., 2.5 V for ±2.5 V swing). The internal 80 mV reference enabled by ENB is intended solely for unidirectional use and cannot support symmetric bidirectional output.

What is the purpose of the exposed pad on the AD8218BCPZ-RL LFCSP package?

The exposed pad on the AD8218BCPZ-RL must be soldered to the PCB ground plane to serve as both a thermal dissipation path and the primary ground return for the internal LDO and amplifier core. Per the datasheet, failure to connect the exposed pad to GND degrades thermal performance and may cause instability or reduced common-mode rejection in high-power sensing applications.

Does the AD8218BCPZ-RL require an external bypass capacitor on the VS pin?

Yes - when the VS pin is used (i.e., not left floating), a standard 0.1 µF ceramic capacitor must be placed between VS and GND, as specified in the Pin Function Descriptions table. This bypass stabilizes the internal LDO regulation. When VS is floating (powered from +IN), no external capacitor is needed on VS, but proper +IN/GND decoupling remains essential for noise immunity.