Bidirectional, Zero Drift,

Current Sense Amplifier

Data Sheet

AD8418

FEATURES

Typical 0.1 µV/°C offset drift

Maximum ±400 µV voltage offset over full temperature range

2.7 V to 5.5 V power supply operating range

Electromagnetic interference (EMI) filters Included

High common-mode input voltage range

−2 V to +70 V operating

−4 V to +85 V survival

Initial gain = 20 V/V

Wide operating temperature range: −40°C to +125°C

Bidirectional operation

Available in 8-lead SOIC and 8-lead MSOP

Common-mode rejection ratio (CMRR): 86 dB, dc to 10 kHz

Qualified for automotive applications

APPLICATIONS

High-side current sensing in

Motor controls

Solenoid controls

Power management

Low-side current sensing

Diagnostic protection

GENERAL DESCRIPTION

The AD8418 is a high voltage, high resolution current shunt

amplifier. It features an initial gain of 20 V/V, with a maximum

±0.15% gain error over the entire temperature range. The

buffered output voltage directly interfaces with any typical

converter. The AD8418 offers excellent input common-mode

rejection from −2 V to +70 V. The AD8418 performs bidirectional

current measurements across a shunt resistor in a variety of

automotive and industrial applications, including motor

control, battery management, and solenoid control.

The AD8418 offers breakthrough performance throughout the

−40°C to +125°C temperature range. It features a zero drift core,

which leads to a typical offset drift of 0.1 µV/°C throughout the

operating temperature range and the common-mode voltage

range. The AD8418 is fully qualified for automotive applications

and includes EMI filters and patented circuitry to enable output

accuracy with pulse-width modulation (PWM) type input

common-mode voltages. The typical input offset voltage is

±200 µV. The AD8418 is offered in 8-lead MSOP and SOIC

packages.

Table 1. Related Devices

Part No.

Description

AD8205

Current sense amplifier, gain = 50

AD8206

Current sense amplifier, gain = 20

AD8207

High accuracy current sense amplifier, gain = 20

AD8210

High speed current sense amplifier, gain = 20

FUNCTIONAL BLOCK DIAGRAM

+

G = 20

OUT

0V

EMI

FILTER

EMI

FILTER

0V

70V

AD8418

+IN

–IN

–

GND

–50A

50A

Figure 1.

Rev. 0

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