High Resolution, Zero-Drift
FEATURES
High common-mode voltage range
4.5 V to 80 V operating
0 V to 85 V survival
Buffered output voltage
Wide operating temperature range: −40°C to +125°C
Excellent ac and dc performance
±100 nV/°C typical offset drift
±100 μV typical offset
±5 ppm/°C typical gain drift
100 dB typical CMRR at dc
APPLICATIONS
High side current sensing
48 V telecom
Power management
Base stations
Unidirectional motor control
Precision high voltage current sources
Current Shunt Monitor
AD8217
FUNCTIONAL BLOCK DIAGRAM
R4
OUT
R3
Figure 1.
–IN
+IN
AD8217
R1
R2
LDO
GND
09161-001
GENERAL DESCRIPTION
The AD8217 is a high voltage, high-resolution current shunt
amplifier. It features a set gain of 20 V/V, with a maximum
±0.35% gain error over the entire temperature range. The
buffered output voltage directly interfaces with any typical
converter. The AD8217 offers excellent common-mode rejection
from 4.5 V to 80 V, and includes an internal LDO, which directly
powers the device from the high voltage rail. Therefore, no additional supply is necessary, provided that the input common-mode
range is 4.5 V to 80 V. The AD8217 performs unidirectional
current measurements across a shunt resistor in a variety of
industrial and telecom applications including motor control,
battery management, and base station power amplifier bias
control.
The AD8217 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 ±100 nV/°C
throughout the operating temperature and common-mode
voltage range. Special attention 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, and the typical input offset voltage is ±100 μV.
The AD8217 is offered in a 8-lead MSOP package and is
specified from −40°C to +125°C.
Rev. A
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 ©2010–2011 Analog Devices, Inc. All rights reserved.
AD8217
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
REVISION HISTORY
3/11—Rev. 0 to Rev. A
Changes to Features.......................................................................... 1
Changes to Figure 18........................................................................ 8
7/10—Revision 0: Initial Version
Amplifier Core............................................................................ 10
Internal LDO............................................................................... 10
Application Notes........................................................................... 11
Output Linearity......................................................................... 11
Applications Information.............................................................. 12
High-Side Current Sensing....................................................... 12
Motor Control Current Sensing............................................... 12
Outline Dimensions....................................................................... 13
Ordering Guide .......................................................................... 13
Rev. A | Page 2 of 16
AD8217
SPECIFICATIONS
T
= −40°C to +125°C, TA = 25°C, RL = 25 kΩ, input common-mode voltage (VCM = 4.5 V) (RL is the output load resistor), unless
OPR
otherwise noted.
Table 1.
Parameter Min Typ Max Unit Test Conditions/Comments
GAIN
Initial 20 V/V
Accuracy ±0.1 % VO ≥ 0.1 V dc, T
Accuracy over Temperature ±0.35 % T
Gain vs. Temperature ±5 ppm/°C T
OPR
OPR
VOLTAGE OFFSET
Offset Voltage (RTI)1 ±250 μV 25°C
Over Temperature (RTI)1 ±300 μV T
Offset Drift ±100 nV/°C T
OPR
OPR
INPUT
Bias Current2 500 μA TA
800 μA T
OPR
Common-Mode Input Voltage Range 4.5 80 V Common-mode continuous
Differential Input Voltage Range3 250 mV Differential input voltage
Common-Mode Rejection (CMRR) 90 100 dB T
OUTPUT
Output Voltage Range Low 0.01 V T
Output Voltage Range High 5 V T
Output Impedance 2 Ω
DYNAMIC RESPONSE
Small Signal −3 dB Bandwidth 500 kHz
Slew Rate 1 V/μs
NOISE
0.1 Hz to 10 Hz, (RTI)1 2.3 μV p-p
Spectral Density, 1 kHz, (RTI)1 110 nV/√Hz
POWER SUPPLY
Operating Range 4.5 80 V
OPR
4
A
4
A
Power regulated from common mode
Quiescent Current Over Temperature 800 μA Throughout input common mode
T
Power Supply Rejection Ratio (PSRR) 90 110 dB
TEMPERATURE RANGE
For Specified Performance −40 +125 °C
1
RTI = referred to input.
2
Refer to for further information on the input bias current. This current varies based on the input common-mode voltage. Additionally, the input bias current
Figure 8
flowing to the +IN pin is also the supply current to the internal LDO.
3
The differential input voltage is specified as 250 mV typical because the output is internally clamped to 5 V. This ensures the output voltage does not exceed 5 V and
can interface and not cause damage to any typical converter, regardless of the high voltage present at the inputs of the AD8217 (up to 80 V).
4
See and for further information on the output range of the AD8217 with various loads. The AD8217 output clamps to a maximum voltage of 5.6 V
Figure 17 Figure 18
when the voltage at pin +IN is greater than 5.6 V. When the voltage at +IN is less than 5.6 V, the output reaches a maximum value of (V
OPR
A
− 100 mV).
+IN
Rev. A | Page 3 of 16
AD8217
ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter Rating
Maximum Input Voltage ( +IN, −IN to GND) 0 V to 85 V
Differential Input Voltage (+IN to –IN) ±1 V
HBM (Human Body Model) ESD Rating ±2000 V
Operating Temperature Range (T
Storage Temperature Range −65°C to +150°C
Output Short-Circuit Duration Indefinite
) −40°C to +125°C
OPR
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
Rev. A | Page 4 of 16
AD8217
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
+IN
1
AD8217
2
NC
TOP VIEW
3
NC
(Not to Scale)
GND
4
NC = NO CO N NECT
Figure 2. Pin Configuration
Table 3. Pin Function Descriptions
Pin No. Mnemonic Description
1 +IN Noninverting Input. Supply pin to the internal LDO.
2 NC No Connect. No internal connection to pin.
3 NC No Connect. No internal connection to pin.
4 GND Ground.
5 OUT Output.
6 NC No Connect. No internal connection to pin.
7 NC No Connect. No internal connection to pin.
8 −IN Inverting Input.
–IN
8
7
NC
6
NC
OUT
5
09161-002
Rev. A | Page 5 of 16
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