High Voltage
V
V
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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
Current Shunt Monitor
AD8211
FUNCTIONAL BLOCK DIAGRAM
IN+
A1
GND
IN–
PROPRIETARY
OFFSET
CIRCUITRY
G = +20
AD8211
Figure 1.
V+
OUT
06824-001
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 commonmode rejection from −2 V to +65 V is independent of the 5 V
supply. The AD8211 performs unidirectional current measurements 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
t
hroughout 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.
Rev. 0
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Anal og Devices for its use, nor for any infringements of patents or ot her
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.
AD8211
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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
REVISION HISTORY
7/07—Revision 0: Initial Version
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
Rev. 0 | Page 2 of 16
AD8211
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SPECIFICATIONS
T
= −40°C to +125°C, TA = 25°C, VS = 5 V, RL = 25 kΩ (RL is the output load resistor), unless otherwise noted.
OPR
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 % T
Gain vs. Temperature −13 ppm/°C T
VOLTAGE OFFSET
Offset Voltage (RTI) ±1 mV 25°C
Over Temperature (RTI) ±2.2 mV T
Offset Drift 5 μV/°C T
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.
OPR
1
OPR
OPR
2
OPR
Rev. 0 | Page 3 of 16
AD8211
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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
tresses above those listed under Absolute Maximum Ratings
S
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
Rev. 0 | Page 4 of 16
AD8211
G
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PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
OUT
1
AD8211
ND
2
1 2 5
1 2 5
V
TOP VIEW
(Not to Scale)
3
IN+
NC = NO CONNECT
Figure 3. Pin Configuration
3 4
3 4
6824-030
Figure 2. Metallization Diagram
V+
5
V
4
IN–
6824-002
Table 3. Pin Function Descriptions
Pin No. Mnemonic X Y Description
1 OUT −277 +466 Buffered Output.
2 GND −140 +466 Ground.
3 V
4 V
IN+
IN−
−228 −519 Noninverting Input.
+229 −519 Inverting Input.
5 V+ +264 +466 Supply.
Rev. 0 | Page 5 of 16
AD8211
–
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TYPICAL PERFORMANCE CHARACTERISTICS
1.2
1.0
0.8
0.6
0.4
0.2
(mV)
0
OSI
V
–0.2
–0.4
–0.6
–0.8
–1.0
–1.2
–40
–20 0 20 40 60 80 100 120
Figure 4. Typical Offset vs. Temperature
140
130
COMMON-MODE VOLTAGE > 5V
120
110
100
COMMON-MODE VOLTAGE < 5V
CMRR (dB)
90
80
70
60
10
Figure 5. Typical CMRR vs. Frequency
2500
2000
1500
1000
500
0
–500
GAIN ERROR (PP M )
–1000
–1500
–2000
–2500
–40
–20 0 20 40 60 80 100 120
Figure 6. Typical Gain Error vs. Temperature
TEMPERATURE (°C)
FREQUNCY (Hz)
TEMPERATURE (°C)
06824-112
06824-114
1M100 1k 10k 100k
06824-113
40
3
5
30
25
20
15
10
5
0
–5
GAIN (dB)
–10
–15
–20
–25
–30
–35
–40
10k
Figure 7. Typical Small Signal Bandwidth (V
100k 1M
FREQUENCY (Hz)
= 200 mV p-p)
OUT
10
9
8
7
6
5
4
3
TOTAL O UTPUT ERROR ( %)
2
1
0
0
5 101520253035404550556065707580859095
DIFFERENTIAL INPUT VOLTAGE (mV)
Figure 8. Total Output Error vs. Differential Input Voltage
510
–515
–520
–525
–530
–535
–540
–545
–550
–555
INPUT BIAS CURRENT (µA)
–560
–565
–570
0 250
25 50 75 100 125 150 175 200 225
DIFFERENTIAL INPUT VOLTAGE (mV)
V
IN+
V
IN–
Figure 9. Input Bias Current vs. Differential Input Voltage,
V
= 0 V
CM
10M
250
06824-107
06824-118
06824-103
Rev. 0 | Page 6 of 16
AD8211
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110
100
100mV/DIV
90
80
70
V
IN+
1V/DIV
INPUT
60
INPUT BIAS CURRENT (µA)
50
40
0 250
25 50 75 100 125 150 175 200 225
DIFFERENTIAL INPUT VOLTAGE (mV)
Figure 10. Input Bias Current vs. Dif
0.8
0.4
0
–0.4
–0.8
–1.2
–1.6
INPUT BIAS CURRENT ( mA)
–2.0
–2.4
–5 65
0 5 10 15 20 25 30 35 40 45 50 55 60
INPUT COMMON-MODE VOLTAGE (V)
V
IN–
ferential Input Voltage,
= 5 V
V
CM
Figure 11. Input Bias Current vs. Input Common-Mode Voltage
4.0
3.5
OUTPUT
06824-104
TIME (500ns/DIV)
06824-110
Figure 13. Fall Time
INPUT
100mV/DIV
1V/DIV
06824-102
TIME (500ns/DIV)
OUTPUT
06824-111
Figure 14. Rise Time
200mV/DIV
3.0
2.5
2.0
SUPPLY CURRENT (mA)
1.5
1.0
–4 65
–202468
COMMON-MODE VOLTAGE (V)
Figure 12. Supply Current vs. Common-Mode Voltage
06824-101
2V/DIV
Figure 15. Differential Overload Recovery (Falling)
Rev. 0 | Page 7 of 16
TIME (1µs/DIV)
INPUT
OUTPUT
06824-109
AD8211
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12.0
INPUT
200mV/DIV
OUTPUT
2V/DIV
TIME (1µs/DIV)
Figure 16. Differential Overload Recovery (Rising)
2V/DIV
0.01/DIV
TIME 5µ s/DIV)
Figure 17. Settling Time (Falling)
2V/DIV
0.01/DIV
TIME 5µ s/DIV)
Figure 18. Settling Time (Rising)
06824-108
06824-120
06824-119
11.5
11.0
10.5
10.0
9.5
9.0
8.5
8.0
7.5
7.0
6.5
6.0
MAXIMUM OUT P UT SINK CURRENT (mA)
5.5
5.0
–40
–20 0 20 40 60 80 100 120 140–30 –10 10 30 50 70 90 110 130 150
TEMPERATURE (°C)
Figure 19. Maximum Output Sink Current vs. Temperature
9.0
8.5
8.0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
MAXIMUM OUT PUT SOURCE CURRENT (mA)
4.0
–40
–20 0 20 40 60 80 100 120 140
TEMPERATURE (°C)
Figure 20. Maximum Output Source Current vs. Temperature
5.0
4.6
4.2
3.8
3.4
3.0
2.6
2.2
OUTPUT VO LTAGE RANGE ( V )
1.8
1.4
1.0
0
12345678
OUTPUT SOURCE CURRENT (mA)
Figure 21. Output Voltage Range vs. Output Source Current
06824-106
06824-105
06824-117
9
Rev. 0 | Page 8 of 16
AD8211
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2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
OUTPUT VO LTAGE RANGE FROM GND (V)
0
0
1234567891011
OUTPUT SINK CURRENT (mA)
Figure 22. Output Voltage Range from GND vs. Output Sink Current
06824-116
12
Rev. 0 | Page 9 of 16
AD8211
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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.
I
SHUNT
R
SHUNT
I
IN
R1
A1
Q1
R
OUT
GND
Figure 23. Simplifi
R
PROPRIETARY
OFFSET
CIRCUITRY
G = +20
AD8211
V+
V
= (I
OUT
SHUNT
06824-022
ed Schematic
× R
SHUNT
) × 20
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
(V
CM
) − (I
SHUNT
× R
SHUNT
)
because negligible current flows through Resistor R. Amplifier
forces the noninverting input to the same potential. Therefore,
A1
the current that flows through Resistor R1, is equal to
I
= (I
IN
This current (I
× R
SHUNT
) is converted back to a voltage via R
IN
SHUNT
)/R1
OUT
. 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
= (I
V
OUT
SHUNT
× R
SHUNT
) × 20
Rev. 0 | Page 10 of 16
AD8211
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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.
he input differential voltage vs. the corresponding output
t
voltage at different common modes.
200
180
160
140
120
100
80
60
OUTPUT VO LTAGE (mV)
40
20
0
0
123456789
DIFFERENTIAL INPUT VOLTAGE (mV)
Figure 24. Gain Linearity Due to Differential and Common-Mode Voltage
Figure 24 shows
IDEAL V
V
OUT
V
OUT
(mV)
OUT
(mV) @ VCM = 0V
(mV) @ VCM = 65V
06824-115
10
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 guardbands. 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.
Rev. 0 | Page 11 of 16
AD8211
Y
Y
Y
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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
t
he 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.
INDUCTIVE
LOAD
SHUNT
SWITCH
CLAMP
DIODE
BATTER
06824-024
GND2V
1
IN+
3
123
OUT
AD8211
V+
4
54
5V
V
IN–
5
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
c
urrent detection signal in as little as 100 ns. This feature is
useful in high current systems where fast shutdown in overcurrent conditions is essential.
AD8214 can also be used to provide an over-
OVERCURRENT
DETECTION (< 100n s)
GND NC –INOUT
8765
AD8214
V
REG
GND2V
AD8211
5V
+IN V
V
S
1234
1
IN+
SHUNT
CLAMP
IN–
5
DIODE
INDUCTIVE
LOAD
SWITCH
BATTER
NC
3
123
OUT
V+
4
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.
INDUCTIVE
GND2V
1
IN+
3
123
OUT
AD8211
V+
4
54
5V
V
IN–
5
Figure 27. Ground-Referenced Shunt Resistor
LOAD
SHUNT
CLAMP
DIODE
SWITCH
BATTER
06824-026
06824-025
Rev. 0 | Page 12 of 16
AD8211
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OUTLINE DIMENSIONS
2.90 BSC
5
1.60 BSC
123
PIN 1
1.30
1.15
0.90
0.15 MAX
COMPLIANT TO JEDEC STANDARDS MO-178-AA
Figure 28. 5-Lead Small Outline Transistor Package [SOT-23]
4
2.80 BSC
0.95 BSC
1.90
BSC
1.45 MAX
0.50
SEATING
0.30
PLANE
Dimensions shown in millimeters
(RJ-5)
0.22
0.08
10°
5°
0°
0.60
0.45
0.30
ORDERING GUIDE
Model Temperature Range Package Description Package Option Branding
AD8211YRJZ-R2
AD8211YRJZ-RL
AD8211YRJZ-RL7
1
Z = RoHS Compliant Part.
1
1
1
−40°C to +125°C 5-Lead SOT-23 RJ-5 Y02
−40°C to +125°C 5-Lead SOT-23 RJ-5 Y02
−40°C to +125°C 5-Lead SOT-23 RJ-5 Y02
Rev. 0 | Page 13 of 16
AD8211
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NOTES
Rev. 0 | Page 14 of 16
AD8211
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NOTES
Rev. 0 | Page 15 of 16
AD8211
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NOTES
©2007 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D06824-0-7/07(0)
Rev. 0 | Page 16 of 16
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