Bidirectional, Zero Drift,
Data Sheet
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. T h e 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
+
I
SHUNT
G = 20
V
CM
= –2V TO +70V V
S
= 2.7V TO 5.5V
V
REF
1
V
REF
2
OUT
0V
V
S
V
S
/2
V
OUT
I
SHUNT
EMI
FILTER
EMI
FILTER
V
CM
0V
70V
AD8418
V
S
+IN
–IN
–
GND
–50A
50A
R
SHUNT
11546-001
Figure 1.
Rev. 0
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