Data Sheet
FEATURES
Typical 0.1 μV/°C offset drift
Maximum ±200 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 continuous
−4 V to +85 V survival
Minimum DC common-mode rejection ratio (CMRR): 90 dB
Initial gain = 20 V/V
Wide operating temperature range
AD8418AWB:
−40°C to +125°C
AD8418AWH:
−40°C to +150°C
Bidirectional operation
Available in 8-lead SOIC and 8-lead MSOP
Qualified for automotive applications
Bidirectional, Zero Drift,
Current Sense Amplifier
AD8418A
GENERAL DESCRIPTION
The
AD8418A
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
AD8418A
offers excellent input common-mode rejection from
−2 V to +70 V. The
AD8418A
performs bidirectional current
measurements across a shunt resistor in a variety of automotive
and industrial applications, including motor control, power
management, and solenoid control.
The
AD8418A
offers breakthrough performance throughout
the −40°C to +150°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
AD8418A
is qualified for automotive applications.
The device 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 ±100 μV. The
AD8418A
is offered in 8-lead MSOP and SOIC
packages.
Table 1. Related Devices
Part No.
AD8205
AD8206
AD8207
AD8210
AD8417
Description
Current sense amplifier, gain = 50
Current sense amplifier, gain = 20
High accuracy current sense amplifier, gain = 20
High speed current sense amplifier, gain = 20
High accuracy current sense amplifier, gain = 60
APPLICATIONS
High-side current sensing in
Motor controls
Solenoid controls
Power management
Low-side current sensing
Diagnostic protection
FUNCTIONAL BLOCK DIAGRAM
V
CM
= –2V TO +70V
V
S
= 2.7V TO 5.5V
70V
V
S
V
REF
1
V
CM
+IN
I
SHUNT
AD8418A
EMI
FILTER
V
S
V
OUT
+
G = 20
0V
R
SHUNT
–IN
50A
EMI
FILTER
OUT
V
S
/2
–
I
SHUNT
0V
–50A
11883-001
GND
V
REF
2
Figure 1.
Rev. B
Document Feedback
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700 ©2013–2017 Analog Devices, Inc. All rights reserved.
Technical Support
www.analog.com
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.
AD8418A
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
General Description ......................................................................... 1
Functional Block Diagram .............................................................. 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Absolute Maximum Ratings ............................................................ 4
ESD Caution .................................................................................. 4
Pin Configuration and Function Descriptions ............................. 5
Typical Performance Characteristics ............................................. 6
Theory of Operation ...................................................................... 11
Output Offset Adjustment ............................................................. 12
Data Sheet
Unidirectional Operation .......................................................... 12
Bidirectional Operation ............................................................. 12
External Referenced Output ..................................................... 13
Splitting the Supply .................................................................... 13
Splitting an External Reference ................................................ 13
Applications Information .............................................................. 14
Motor Control ............................................................................. 14
Solenoid Control ........................................................................ 15
Outline Dimensions ....................................................................... 16
Ordering Guide .......................................................................... 17
Automotive Products ................................................................. 17
REVISION HISTORY
4/2017—Rev. A to Rev. B
Changes to Features Section and General Description Section....... 1
Changes to Table 2 ............................................................................ 3
Changes to Table 3 ............................................................................ 4
Change to Figure 18 ......................................................................... 8
Added Figure 19 and Figure 20; Renumbered Sequentially ....... 8
12/2014—Rev. 0 to Rev. A
Added AD8418AWH ......................................................... Universal
Changes to Features Section and General Description Section........ 1
Changes to Specifications Section and Table 2 ............................. 3
Changes to Table 3 ............................................................................ 4
Changes to Ordering Guide .......................................................... 16
11/2013—Revision 0: Initial Version
Rev. B | Page 2 of 17
Data Sheet
SPECIFICATIONS
AD8418A
T
A
= −40°C to +125°C (operating temperature range) for the
AD8418AWB,
T
A
= −40°C to +150°C for the
AD8418AWH,
V
S
= 5 V, unless
otherwise noted.
Table 2.
Parameter
GAIN
Initial
Error Over Temperature
Gain vs. Temperature
VOLTAGE OFFSET
Offset Voltage, Referred to the Input, RTI
Over Temperature, RTI
Offset Drift
INPUT
Input Bias Current
Input Voltage Range
Common-Mode Rejection Ratio (CMRR)
OUTPUT
Output Voltage Range
Output Resistance
Maximum Capacitive Load
DYNAMIC RESPONSE
Small Signal −3 dB Bandwidth
Slew Rate
NOISE
0.1 Hz to 10 Hz (RTI)
Spectral Density, 1 kHz, RTI
OFFSET ADJUSTMENT
Ratiometric Accuracy
1
Accuracy, Referred to the Output (RTO)
Output Offset Adjustment Range
POWER SUPPLY
Operating Range
Quiescent Current Over Temperature
Test Conditions/Comments
Min
Typ
20
Specified temperature range
−5
25°C
Specified temperature range
−0.4
±100
+0.1
130
Common mode, continuous
Specified temperature range, f = dc
f = dc to 10 kHz
R
L
= 25 kΩ
No continuous oscillation
−2
90
+70
100
86
V
S
− 0.032
2
0
250
1
2.3
110
Divider to supplies
Voltage applied to V
REF
1 and V
REF
2 in parallel
V
S
= 5 V
0.4985
0.032
2.7
V
OUT
= 0.1 V dc
AD8418AWB
AD8418AWH
80
Operating temperature range
AD8418AWB
AD8418AWH
0.5015
±1
V
S
− 0.032
5.5
4.1
4.2
500
±200
+0.4
±0.15
+5
Max
Unit
V/V
%
ppm/°C
µV
µV
µV/°C
µA
V
dB
dB
V
Ω
pF
kHz
V/µs
µV p-p
nV/√Hz
V/V
mV/V
V
V
mA
mA
dB
0.032
Power Supply Rejection Ratio
TEMPERATURE RANGE
For Specified Performance
−40
−40
+125
+150
°C
°C
1
The offset adjustment is ratiometric to the power supply when V
REF
1 and V
REF
2 are used as a divider between the supplies.
Rev. B | Page 3 of 17
AD8418A
ABSOLUTE MAXIMUM RATINGS
Table 3.
Parameter
Supply Voltage
Input Voltage Range
Continuous
Survival
Differential Input Survival
Reverse Supply Voltage
ESD Human Body Model (HBM)
Operating Temperature Range
AD8418AWB
AD8418AWH
Storage Temperature Range
Output Short-Circuit Duration
SOIC Package
θ
JA
Thermal Resistance
MSOP Package
θ
JA
Thermal Resistance
Rating
6V
−2 V to +70 V
−4 V to +85 V
±5.5 V
0.3 V
±2000 V
−40°C to +125°C
−40°C to +150°C
−65°C to +150°C
Indefinite
127.4°C/W
134.5°C/W
Data Sheet
Stresses at or above those listed under Absolute Maximum
Ratings may cause permanent damage to the product. This is a
stress rating only; functional operation of the product at these
or any other conditions above those indicated in the operational
section of this specification is not implied. Operation beyond
the maximum operating conditions for extended periods may
affect product reliability.
ESD CAUTION
Rev. B | Page 4 of 17
Data Sheet
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
–IN
1
GND
2
V
REF
2
3
NC
4
8
AD8418A
+IN
V
REF
1
V
S
OUT
11883-002
AD8418A
TOP VIEW
(Not to Scale)
7
6
5
NC = NO CONNECT. DO NOT
CONNECT TO THIS PIN.
Figure 2. Pin Configuration
Table 4. Pin Function Descriptions
Pin No.
1
2
3
4
5
6
7
8
Mnemonic
−IN
GND
V
REF
2
NC
OUT
V
S
V
REF
1
+IN
Description
Negative Input.
Ground.
Reference Input 2.
No Connect. Do not connect to this pin.
Output.
Supply.
Reference Input 1.
Positive Input.
Rev. B | Page 5 of 17
