High Voltage
Current Shunt Monitor
AD8211
Rev. 0
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.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700 www.analog.com
Fax: 781.461.3113 ©2007 Analog Devices, Inc. All rights reserved.
FEATURES
±4000 V HBM ESD
High common-mode voltage range
−2 V to +65 V operating
−3 V to +68 V survival
Buffered output voltage
Wide operating temperature range
5-lead SOT: −40°C to +125°C
Excellent ac and dc performance
5 μV/°C typical offset drift
−13 ppm/°C typical gain drift
120 dB typical CMRR at dc
APPLICATIONS
High-side current sensing
Motor controls
Transmission controls
Engine management
Suspension controls
Vehicle dynamic controls
DC-to-dc converters
FUNCTIONAL BLOCK DIAGRAM
06824-001
V
IN+
V+
OUT
G = +20
AD8211
A1
PROPRIETARY
OFFSET
CIRCUITRY
V
IN–
GND
Figure 1.
GENERAL DESCRIPTION
The AD8211 is a high voltage, precision current shunt amplifier.
It features a set gain of 20 V/V, with a typical ±0.5% gain error
over the entire temperature range. The buffered output voltage
directly interfaces with any typical converter. Excellent common-
mode rejection from −2 V to +65 V is independent of the 5 V
supply. The AD8211 performs unidirectional current measure-
ments across a shunt resistor in a variety of industrial and
automotive applications, such as motor control, solenoid
control, or battery management.
Special circuitry is devoted to output linearity being maintained
throughout the input differential voltage range of 0 mV to 250 mV,
regardless of the common-mode voltage present. The AD8211
has an operating temperature range of −40°C to +125°C and is
offered in a small 5-lead SOT package.
AD8211
Rev. 0 | Page 2 of 16
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications....................................................................................... 1
Functional Block Diagram .............................................................. 1
General Description ......................................................................... 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 ...................................................................... 10
Application Notes ........................................................................... 11
Output Linearity......................................................................... 11
Applications Information.............................................................. 12
High-Side Current Sense with a Low-Side Switch................. 12
High-Side Current Sensing ....................................................... 12
Low-Side Current Sensing ........................................................ 12
Outline Dimensions ....................................................................... 13
Ordering Guide .......................................................................... 13
REVISION HISTORY
7/07—Revision 0: Initial Version
AD8211
Rev. 0 | Page 3 of 16
SPECIFICATIONS
TOPR = −40°C to +125°C, TA = 25°C, VS = 5 V, RL = 25 kΩ (RL is the output load resistor), unless otherwise noted.
Table 1.
Parameter Min Typ Max Unit Conditions
GAIN
Initial 20 V/V
Accuracy ±0.25 % VO ≥ 0.1 V dc
Accuracy Over Temperature ±0.35 % TOPR
Gain vs. Temperature −13 ppm/°C TOPR1
VOLTAGE OFFSET
Offset Voltage (RTI) ±1 mV 25°C
Over Temperature (RTI) ±2.2 mV TOPR
Offset Drift 5 μV/°C TOPR2
INPUT
Input Impedance
Differential 5 kΩ
Common Mode 5 MΩ Common-mode voltage > 5 V
3.5 kΩ Common-mode voltage < 5 V
Common-Mode Input Voltage Range −2 +65 V Common-mode continuous
Differential Input Voltage Range 250 mV Differential input voltage
Common-Mode Rejection 100 120 dB TA, f = dc, VCM > 5 V, see Figure 5
80 90 dB TA, f = dc, VCM < 5 V, see Figure 5
OUTPUT
Output Voltage Range Low 0.1 0.05 V
Output Voltage Range High 4.95 4.9 V
Output Impedance 2 Ω
DYNAMIC RESPONSE
Small Signal −3 dB Bandwidth 500 kHz
Slew Rate 4.5 V/μs
NOISE
0.1 Hz to 10 Hz, RTI 7 μV p-p
Spectral Density, 1 kHz, RTI 70 nV/√Hz
POWER SUPPLY
Operating Range 4.5 5.5 V
Quiescent Current Over Temperature 1.2 2.0 mA VCM > 5 V3, see Figure 12
Power Supply Rejection Ratio 76 dB
TEMPERATURE RANGE
For Specified Performance −40 +125 °C
1 The mean of the gain drift distribution is typically −13 ppm/°C, with a σ = 3 ppm/°C.
2 The mean of the offset drift distribution is typically +5 μV/°C, with a σ = 3 μV/°C.
3 When the input common-mode voltage is less than 5 V, the supply current increases, which can be calculated by IS = −0.275 (VCM) + 2.5.
AD8211
Rev. 0 | Page 4 of 16
ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter Rating
Supply Voltage 12.5 V
Continuous Input Voltage −3 V to +68 V
Reverse Supply Voltage −0.3 V
HBM (Human Body Model) ESD Rating ±4000 V
CDM (Charged Device Model) ESD Rating ±1000 V
Operating Temperature Range −40°C to +125°C
Storage Temperature Range −65°C to +150°C
Output Short-Circuit Duration Indefinite
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
ESD CAUTION
AD8211
Rev. 0 | Page 5 of 16
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
0
6824-030
1 2 5
3 4
1 2 5
3 4
Figure 2. Metallization Diagram
0
6824-002
OUT
1
G
ND
2
V
IN+ 3
V+
5
V
IN–
4
NC = NO CONNECT
AD8211
TOP VIEW
(No t to Scale)
Figure 3. Pin Configuration
Table 3. Pin Function Descriptions
Pin No. Mnemonic X Y Description
1 OUT −277 +466 Buffered Output.
2 GND −140 +466 Ground.
3 VIN+ −228 −519 Noninverting Input.
4 VIN− +229 −519 Inverting Input.
5 V+ +264 +466 Supply.
AD8211
Rev. 0 | Page 6 of 16
TYPICAL PERFORMANCE CHARACTERISTICS
1.2
–1.2
–40
06824-112
TEM PE RAT URE ( ° C)
VOSI (mV)
–20 0 20 40 60 80 100 120
1.0
0.6
0.8
0.4
0.2
0
–0.2
–0.4
–0.6
–0.8
–1.0
Figure 4. Typical Offset vs. Temperature
140
6010
06824-114
FREQ UNCY (Hz )
CMRR (d B)
1M100 1k 10k 100k
130
120
110
100
90
80
70
COMMON-MODE VOLTAGE > 5V
COMMON-MODE VOLTAGE < 5V
Figure 5. Typical CMRR vs. Frequency
2500
–2500
–40
06824-113
TEMPERATURE (°C)
GAI N E RRO R (PPM)
–20 0 20 40 60 80 100 120
2000
1500
1000
500
0
–500
–1000
–1500
–2000
Figure 6. Typical Gain Error vs. Temperature
40
–40
10k
06824-107
FREQUENCY ( Hz )
GAIN (dB)
10M
–5
–10
–15
–20
–25
20
30
25
35
15
10
5
0
–30
–35
100k 1M
Figure 7. Typical Small Signal Bandwidth (VOUT = 200 mV p-p)
10
00
06824-118
DIFFERENTIAL INPUT VOLTAGE (mV)
TO TAL OUT PUT ERRO R ( %)
250
9
8
7
6
5
4
3
2
1
5 101520253035404550556065707580859095
Figure 8. Total Output Error vs. Differential Input Voltage
–
510
–570 0 250
06824-103
DIFFERENTIAL INPUT VOLTAGE (mV)
INPUT BIAS CURRE NT ( µA)
–515
–520
–525
–530
–535
–540
–545
–550
–555
–560
–565
25 50 75 100 125 150 175 200 225
V
IN+
V
IN–
Figure 9. Input Bias Current vs. Differential Input Voltage,
VCM = 0 V
AD8211
Rev. 0 | Page 7 of 16
110
400 250
06824-104
DIFFERENTIAL INPUT VOLTAGE (mV)
INPUT BIAS CURRE NT ( µA)
100
90
80
70
60
50
25 50 75 100 125 150 175 200 225
VIN+
VIN–
Figure 10. Input Bias Current vs. Differential Input Voltage,
VCM = 5 V
0.8
–2.4–5 65
06824-102
INPUT COMMON-MODE VO L T AGE (V)
INPUT BIAS CURRENT ( mA)
0.4
0
–0.4
–0.8
–1.2
–1.6
–2.0
0 5 10 15 20 25 30 35 40 45 50 55 60
Figure 11. Input Bias Current vs. Input Common-Mode Voltage
4.0
1.0–4 65
06824-101
COMMON-MODE VOL T AGE (V)
SUPPLY CURRENT ( mA)
3.5
3.0
2.5
2.0
1.5
–202468
Figure 12. Supply Current vs. Common-Mode Voltage
06824-110
TIME (500ns/DIV)
100mV/DIV
OUTPUT
1V/DIV
INPUT
Figure 13. Fall Time
06824-111
TIME (500ns/DIV)
100mV/DIV OUTPUT
1V/DIV
INPUT
Figure 14. Rise Time
06824-109
TIME (1µs/DIV)
200mV/DIV
OUTPUT
2V/DIV
INPUT
Figure 15. Differential Overload Recovery (Falling)
AD8211
Rev. 0 | Page 8 of 16
06824-108
TIME (1µs/DIV)
200mV/DIV
OUTPUT
2V/DIV
INPUT
Figure 16. Differential Overload Recovery (Rising)
06824-120
TIME 5µs/DIV)
2V/DIV
0.01/DIV
Figure 17. Settling Time (Falling)
06824-119
TIME 5µs/DIV)
2V/DIV
0.01/DIV
Figure 18. Settling Time (Rising)
12.0
5.0
–40
06824-106
TEM PE RAT URE ( ° C)
MAXI M UM OUT PUT SINK CURRENT ( mA)
–20 0 20 40 60 80 100 120 140–30 –10 10 30 50 70 90 110 130 150
8.5
8.0
7.5
7.0
6.5
11.0
11.5
10.5
10.0
9.5
9.0
6.0
5.5
Figure 19. Maximum Output Sink Current vs. Temperature
9.0
4.0
–40
06824-105
TE M P ERATURE ( °C)
MAXI MUM OUTPUT S OURCE CURRENT (mA)
–20 0 20 40 60 80 100 120 140
8.5
8.0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
Figure 20. Maximum Output Source Current vs. Temperature
5.0
1.0 0
06824-117
OUT P UT SOURCE CURRENT (mA)
OUT P UT VO LTAGE RANG E ( V )
9
4.6
4.2
3.8
3.4
3.0
2.6
2.2
1.8
1.4
12345678
Figure 21. Output Voltage Range vs. Output Source Current
AD8211
Rev. 0 | Page 9 of 16
2.0
00
06824-116
OUTPUT S INK CURRENT ( mA)
OUT P UT VO LTAGE RANG E FROM GND (V)
12
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
1234567891011
Figure 22. Output Voltage Range from GND vs. Output Sink Current
AD8211
Rev. 0 | Page 10 of 16
THEORY OF OPERATION
In typical applications, the AD8211 amplifies a small differential
input voltage generated by the load current flowing through
a shunt resistor. The AD8211 rejects high common-mode
voltages (up to 65 V) and provides a ground-referenced,
buffered output that interfaces with an analog-to-digital converter
(ADC). Figure 23 shows a simplified schematic of the AD8211.
06824-022
V+
V
OUT
= (I
SHUNT
× R
SHUNT
) × 20
G = +20
AD8211
A1
PROPRIETARY
OFFSET
CIRCUITRY
GND
R1
R
OUT
Q1
R
I
SHUNT
I
IN
R
SHUNT
Figure 23. Simplified Schematic
A load current flowing through the external shunt resistor
produces a voltage at the input terminals of the AD8211. The
input terminals are connected to Amplifier A1 by Resistor R
and Resistor R1. The inverting terminal, which has very high
input impedance is held to
(VCM) − (ISHUNT × RSHUNT)
because negligible current flows through Resistor R. Amplifier
A1 forces the noninverting input to the same potential. Therefore,
the current that flows through Resistor R1, is equal to
IIN = (ISHUNT × RSHUNT)/R1
This current (IIN) is converted back to a voltage via ROUT. The
output buffer amplifier has a gain of 20 V/V and offers excellent
accuracy as the internal gain setting resistors are precision trimmed
to within 0.01% matching. The resulting output voltage is equal to
VOUT = (ISHUNT × RSHUNT) × 20
AD8211
Rev. 0 | Page 11 of 16
APPLICATION NOTES
OUTPUT LINEARITY
In all current sensing applications, and especially in automotive
and industrial environments where the common-mode voltage
can vary significantly, it is important that the current sensor
maintain the specified output linearity, regardless of the input
differential or common-mode voltage. The AD8211 contains
specific circuitry on the input stage, which ensures that even
when the differential input voltage is very small, and the
common-mode voltage is also low (below the 5 V supply),
the input-to-output linearity is maintained. Figure 24 shows
the input differential voltage vs. the corresponding output
voltage at different common modes.
200
00
06824-115
DIFFERENTIAL INPUT VOLTAGE (mV)
OUT P UT VO LTAGE (mV )
10
180
160
140
120
100
80
60
40
20
123456789
IDEAL V
OUT
(mV)
V
OUT
(mV) @ V
CM
= 0V
V
OUT
(mV) @ V
CM
= 65V
Figure 24. Gain Linearity Due to Differential and Common-Mode Voltage
Regardless of the common mode, the AD8211 provides a
correct output voltage when the input differential is at least
2 mV, which is due to the voltage range of the output amplifier
that can go as low as 33 mV typical. The specified minimum
output amplifier voltage is 100 mV to provide sufficient guard-
bands. The ability of the AD8211 to work with very small
differential inputs, regardless of the common-mode voltage,
allows for more dynamic range, accuracy, and flexibility in any
current sensing application.
AD8211
Rev. 0 | Page 12 of 16
APPLICATIONS INFORMATION
HIGH-SIDE CURRENT SENSE WITH A LOW-SIDE
SWITCH
In such load control configurations, the PWM-controlled
switch is ground referenced. An inductive load (solenoid) is tied
to a power supply. A resistive shunt is placed between the switch
and the load (see Figure 25). An advantage of placing the shunt on
the high side is that the entire current, including the recirculation
current, can be measured because the shunt remains in the loop
when the switch is off. In addition, diagnostics can be enhanced
because shorts to ground can be detected with the shunt on the
high side. In this circuit configuration, when the switch is
closed, the common-mode voltage moves down to near the
negative rail. When the switch is opened, the voltage reversal
across the inductive load causes the common-mode voltage to
be held one diode drop above the battery by the clamp diode.
06824-024
GND
2
V
IN+
V
IN–
1
5
OUT
V+
3
4
AD8211
5V
INDUCTIVE
LOAD CLAMP
DIODE
SHUNT
SWITCH
BATTER
Y
123
54
Figure 25. Low-Side Switch
HIGH-SIDE CURRENT SENSING
In this configuration, the shunt resistor is referenced to the
battery. High voltage is present at the inputs of the current sense
amplifier. In this mode, the recirculation current is again measured
and shorts to ground can be detected. When the shunt is battery
referenced, the AD8211 produces a linear ground-referenced
analog output. An AD8214 can also be used to provide an over-
current detection signal in as little as 100 ns. This feature is
useful in high current systems where fast shutdown in over-
current conditions is essential.
06824-025
GND
2
VIN+
VIN–
1
5
OUT
V+
3
4
AD8211
5V
INDUCTIVE
LOAD
CLAMP
DIODE
SHUNT
SWITCH
BATTER
Y
1234
8765
AD8214
GND NC –INOUT
VREG +IN VS
NC
OVERCURRENT
DETECTION (<100ns)
123
54
Figure 26. Battery-Referenced Shunt Resistor
LOW-SIDE CURRENT SENSING
In systems where low-side current sensing is preferred, the
AD8211 provides an integrated solution with great accuracy.
Ground noise is rejected, CMRR is typically higher than 90 dB,
and output linearity is not compromised, regardless of the input
differential voltage.
06824-026
GND
2
V
IN+
V
IN–
1
5
OUT
V+
3
4
AD8211
5V
INDUCTIVE
LOAD CLAMP
DIODE
SHUNT
BATTER
Y
SWITCH
123
54
Figure 27. Ground-Referenced Shunt Resistor
AD8211
Rev. 0 | Page 13 of 16
OUTLINE DIMENSIONS
PIN 1
1.60 BSC 2.80 BS C
1.90
BSC
0.95 BSC
5
123
4
0.22
0.08 10°
5°
0°
0.50
0.30
0.15 MAX SEATING
PLANE
1.45 MAX
1.30
1.15
0.90
2.90 BSC
0.60
0.45
0.30
COMP LIANT TO J EDE C STANDARDS MO-178- AA
Figure 28. 5-Lead Small Outline Transistor Package [SOT-23]
(RJ-5)
Dimensions shown in millimeters
ORDERING GUIDE
Model Temperature Range Package Description Package Option Branding
AD8211YRJZ-R21−40°C to +125°C 5-Lead SOT-23 RJ-5 Y02
AD8211YRJZ-RL1−40°C to +125°C 5-Lead SOT-23 RJ-5 Y02
AD8211YRJZ-RL71−40°C to +125°C 5-Lead SOT-23 RJ-5 Y02
1 Z = RoHS Compliant Part.
AD8211
Rev. 0 | Page 14 of 16
NOTES
AD8211
Rev. 0 | Page 15 of 16
NOTES
AD8211
Rev. 0 | Page 16 of 16
NOTES
©2007 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D06824-0-7/07(0)
