Datasheet AD8418 (Analog Devices)

Bidirectional, Zero Drift, Current Sense Amplifier Data Sheet AD8418 FEATURES GENERAL DESCRIPTION Typical 0.1 µV/°C offset drift
The AD8418 is a high voltage, high resolution current shunt
Maximum ±400 µV voltage offset over full temperature range
amplifier. It features an initial gain of 20 V/V, with a maximum
2.7 V to 5.5 V power supply operating range
±0.15% gain error over the entire temperature range. The
Electromagnetic interference (EMI) filters Included
buffered output voltage directly interfaces with any typical
High common-mode input voltage range
converter. The AD8418 offers excel ent input common-mode
−2 V to +70 V operating
rejection from −2 V to +70 V. The AD8418 performs bidirectional
−4 V to +85 V survival
current measurements across a shunt resistor in a variety of
Initial gain = 20 V/V
automotive and industrial applications, including motor
Wide operating temperature range: −40°C to +125°C
control, battery management, and solenoid control.
Bidirectional operation Available in 8-lead SOIC and 8-lead MSOP
The AD8418 offers breakthrough performance throughout the
Common-mode rejection ratio (CMRR): 86 dB, dc to 10 kHz
−40°C to +125°C temperature range. It features a zero drift core,
Qualified for automotive applications
which leads to a typical offset drift of 0.1 µV/°C throughout the

operating temperature range and the common-mode voltage
APPLICATIONS
range. The AD8418 is fully qualified for automotive applications and includes EMI filters and patented circuitry to enable output
High-side current sensing in
accuracy with pulse-width modulation (PWM) type input
Motor controls
common-mode voltages. The typical input offset voltage is
Solenoid controls
±200 µV. The AD8418 is offered in 8-lead MSOP and SOIC
Power management
packages.
Low-side current sensing Diagnostic protection 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 VCM = –2V TO +70V VS = 2.7V TO 5.5V 70V V V S REF1 VOUT V V S CM AD8418 +IN EMI + I FILTER SHUNT 0V OUT G = 20 RSHUNT VS/2 –IN EMI – 50A FILTER ISHUNT 0V GND VREF2 –50A
001 1546- 1 Figure 1.
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Document Outline Features Applications General Description Functional Block Diagram Table of Contents Revision History Specifications Absolute Maximum Ratings ESD Caution Pin Configuration and Function Descriptions Typical Performance Characteristics Theory of Operation Output Offset Adjustment Unidirectional Operation Ground Referenced Output VS Referenced Output Bidirectional Operation External Referenced Output Splitting the Supply Splitting an External Reference Applications Information Motor Control 3-Phase Motor Control H-Bridge Motor Control Solenoid Control High-Side Current Sense with a Low-Side Switch High-Side Current Sense with a High-Side Switch High Rail Current Sensing Outline Dimensions Ordering Guide Automotive Products