±8000 AEC-Q100 qualified filters included High common-mode voltage ran
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High Voltage, Precision Difference Amplifier AD8209
±8000 AEC-Q100 qualified filters included High common-mode voltage range operating survival Buffered output voltage Gain Low-pass filter (single-pole two-pole) Wide operating temperature range 8-lead MSOP: -40°C +125°C Excellent performance voltage offset ppm/°C typical gain drift CMRR minimum
FILTER FILTER FILTER
AD8209
Figure
APPLICATIONS
High-side current sensing Motor controls Solenoid controls Power management Low-side current sensing Diagnostic protection
GENERAL DESCRIPTION
AD8209 single-supply difference amplifier ideal amplifying low-pass filtering small differential voltages presence large common-mode voltage. input commonmode voltage range extends from single supply. AD8209 qualified AEC-Q100 specifications. amplifier offers enhanced input overvoltage protection, includes filtering. Automotive applications demand robust, precision components improved system control. AD8209 provides excellent performance, minimizing errors application. Typical offset gain drift MSOP package less than V/°C ppm/°C, respectively. device also delivers minimum CMRR from kHz. AD8209 features externally accessible resistor output preamplifier (A1), which used lowpass filtering establishing gains other than
Rev.
Information furnished Analog Devices believed accurate reliable. However, responsibility assumed Analog Devices use, infringements patents other rights third parties that result from use. Specifications subject change without notice. license granted implication otherwise under patent patent rights Analog Devices. Trademarks registered trademarks property their respective owners.
Technology Way, P.O. 9106, Norwood, 02062-9106, U.S.A. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 ©2009 Analog Devices, Inc. rights reserved.
08461-001
AD8209 TABLE CONTENTS
Features Applications Functional Block Diagram General Description Revision History Specifications. Absolute Maximum Ratings. Caution Configuration Function Descriptions Typical Performance Characteristics Theory Operation Applications Information High-Side Current Sensing with Low-Side Switch High-Rail Current Sensing Low-Side Current Sensing Gain Adjustment Gain Trim Low-Pass Filtering High Line Current Sensing with Gain Adjustment Outline Dimensions Ordering Guide
REVISION HISTORY
10/09-Revision Initial Version
Rev. Page
AD8209 SPECIFICATIONS
TOPR -40°C +125°C, 25°C, output load resistor), unless otherwise noted. Table
Parameter SYSTEM GAIN Initial Error Temperature Gain Drift VOLTAGE OFFSET Initial Input Offset (Referred Input [RTI]) Input Offset (RTI) Over Temperature Voltage Offset Temperature INPUT Input Impedance Differential Common Mode (Continuous) CMRR PREAMPLIFIER (A1) Gain Gain Error Output Voltage Range Output Resistance OUTPUT BUFFER (A2) Gain Gain Error Output Voltage Range Input Bias Current Output Resistance DYNAMIC RESPONSE System Bandwidth Slew Rate NOISE Spectral Density, (RTI) POWER SUPPLY Operating Range Quiescent Current Quiescent Current Temperature PSRR TEMPERATURE RANGE Specified Performance TOPR
Test Conditions
Unit ppm/°C V/°C
0.075 VOUT TOPR TOPR 0.15 TOPR TOPR
±0.3
kHz, TOPR
nV/Hz
0.05 VOUT TOPR -0.3 0.05 +0.3
0.075 VOUT TOPR differential Input TOPR TOPR frequency 0.01 p-p, VOUT 0.14 0.28 VOUT step
-0.3 0.075
+0.3
Typical, VOUT TOPR TOPR
+125
input common-mode voltage. Source imbalance AD8209 preamplifier exceeds CMRR kHz. However, because output available only resistor, even small amount pin-topin capacitance between pins pins might couple input common-mode signal larger than greatly attenuated preamplifier output. effect pin-to-pin coupling neglected applications using filter capacitor from GND. output voltage range AD8209 varies depending load resistance temperature. additional information this specification, refer Figure Figure
Rev. Page
AD8209 ABSOLUTE MAXIMUM RATINGS
Table
Parameter Supply Voltage Continuous Input Voltage (Common Mode) Differential Input Voltage Reversed Supply Voltage Protection Human Body Model Operating Temperature Range Storage Temperature Range Output Short-Circuit Duration Lead Temperature Range (Soldering sec) Rating ±8000 -40°C +125°C -65°C +150°C Indefinite 300°C
Stresses above those listed under Absolute Maximum Ratings cause permanent damage device. This stress rating only; functional operation device these other conditions above those indicated operational section this specification implied. Exposure absolute maximum rating conditions extended periods affect device reliability.
CAUTION
Rev. Page
AD8209 CONFIGURATION FUNCTION DESCRIPTIONS
08461-002
AD8209
VIEW (Not Scale)
08461-003
CONNECT
Figure Configuration
Figure Metallization Photograph
Table Function Descriptions
Mnemonic Coordinates -322 +563 -321 +208 -321 -321 -214 +321 -388 +322 +322 +363 +561 Description Inverting Input Ground Preamplifier (A1) Output Buffer (A2) Input Buffer (A2) Output Connect Supply Noninverting Input
Rev. Page
AD8209 TYPICAL PERFORMANCE CHARACTERISTICS
TOPR -40°C +125°C, 25°C, output load resistor), unless otherwise noted.
0.70 0.55 0.40
1500 1250 1000
VOSI (mV)
0.10 -0.05 -0.20 -0.35 -0.50 -0.65
08461-004
GAIN ERROR (ppm)
0.25
-250 -500 -750
08461-005
08461-007 08461-006
-0.80
TEMPERATURE (°C)
-1000 TEMPERATURE (°C)
Figure Typical Offset Drift Temperature
Figure Typical Gain Error Temperature
GAIN (dB)
0.47
TOTAL INPUT BIAS CURRENT (mA)
08461-022
0.42 0.37 0.32 0.27 0.22 0.17 0.12 0.07 0.02
100k FREQUENCY (Hz)
-0.03
INPUT COMMON-MODE
Figure Typical Small-Signal Bandwidth
Figure Total Input Bias Current Common-Mode Voltage, with Pins Connected (Shorted)
+25°C -40°C
INPUT BIAS CURRENT (nA)
+125°C
-40°C
CMRR (dB)
+25°C +125°C
08461-012
100k
INPUT VOLTAGE
FREQUENCY (Hz)
Figure Typical CMRR Frequency
Figure Input Bias Current Input Voltage Temperature
Rev. Page
AD8209
12.0
OUTPUT VOLTAGE RANGE
08461-008
MAXIMUM OUTPUT SINK CURRENT (mA)
11.5 11.0 10.5 10.0 TEMPERATURE (°C)
08461-011
OUTPUT SINK CURRENT (mA)
Figure Maximum Output Sink Current Temperature
Figure Output Voltage Range from Output Sink Current
MAXIMUM OUTPUT SOURCE CURRENT (mA)
100mV/DIV
INPUT
OUTPUT
500mV/DIV
08461-018
08461-009
TIME (2µs/DIV)
TEMPERATURE (°C)
Figure Maximum Output Source Current Temperature
Figure Rise Time
OUTPUT VOLTAGE RANGE
100mV/DIV
08461-010
INPUT
500mV/DIV
OUTPUT
08461-017
OUTPUT SOURCE CURRENT (mA)
TIME (2µs/DIV)
Figure Output Voltage Range Output Source Current
Figure Fall Time
Rev. Page
AD8209
200mV/DIV
INPUT
2V/DIV
2V/DIV
0.01%/DIV
OUTPUT
08461-014 08461-016
TIME (2µs/DIV)
TIME (20µs/DIV)
Figure Differential Overload Recovery, Rising
Figure Settling Time, Falling
+125°C +25°C -40°C
200mV/DIV
INPUT
2V/DIV
COUNT
OUTPUT
08461-013
TIME (2µs/DIV)
(mV)
Figure Differential Overload Recovery, Falling
Figure Offset Distribution
2V/DIV
COUNT
0.01%/DIV
08461-015
TIME (20µs/DIV)
OFFSET DRIFT (µV/°C)
Figure Settling Time, Rising
Figure Offset Drift Distribution
Rev. Page
08461-020
08461-019
AD8209
1400 1200 1000
COUNT
GAIN DRIFT (ppm/°C)
Figure Gain Drift Distribution
08461-021
Rev. Page
AD8209 THEORY OPERATION
AD8209 single-supply difference amplifier typically used amplify small differential voltage presence rapidly changing, high common-mode voltages. AD8209 consists amplifiers A2), resistor network, small voltage reference, bias circuit (not shown); Figure input attenuators preceding consist which feature combined series resistance approximately 20%. purpose these resistors attenuate input voltage match input voltage range This balanced resistor network attenuates common-mode signal ratio 1/14. amplifier inputs held within power supply range, even exceed supply fall below common (ground). reference voltage biases attenuator above ground, allowing Amplifier operate presence negative common-mode voltages. input resistor network also attenuates normal (differential) mode voltages. Therefore, features gain provide total system gain, from output equal V/V, shown following equation: Gain (A1) 1/14 (V/V) (V/V) precision trimmed, resistor placed series with output Amplifier user access this resistor external (A1). low-pass filter easily implemented connecting placing capacitor ground (see Figure 32). value providing gain Amplifier When connecting together, AD8209 provides total system gain equal Total Gain (V/V) (V/V) (V/V) output (the pin). ratios trimmed high level precision, allowing typical CMRR value that exceeds This performance accomplished laser trimming resistor ratio matching better than 0.01%.
RFILTER
350mV
08461-025
Figure Simplified Schematic
Rev. Page
AD8209 APPLICATIONS INFORMATION
HIGH-SIDE CURRENT SENSING WITH LOW-SIDE SWITCH
load control configurations high-side current sensing with low-side switch, PWM-controlled switch ground referenced. inductive load (solenoid) connects power supply/battery. resistive shunt placed between switch load (see Figure 24). advantage placing shunt high side that entire current, including recirculation current, monitored because shunt remains loop when switch off. addition, shorts ground detected with shunt high side, enhancing diagnostics control loop. this circuit configuration, when switch closed, commonmode voltage moves down near negative rail. When switch opened, voltage reversal across inductive load causes common-mode voltage held diode drop above battery clamp diode.
HIGH-RAIL CURRENT SENSING
high-rail current-sensing configuration, shunt resistor referenced battery. High voltage present inputs current-sense amplifier. When shunt battery referenced, AD8209 produces linear ground-referenced analog output. Additionally, AD8214 used provide overcurrent detection signal little (see Figure 26). This feature useful high current systems where fast shutdown overcurrent conditions essential.
OVERCURRENT DETECTION (<100ns)
AD8214
VREG
CLAMP DIODE
CLAMP DIODE
INDUCTIVE LOAD
OUTPUT
SHUNT
BATTERY
BATTERY
SHUNT
AD8209
AD8209
INDUCTIVE LOAD
SWITCH
08461-028
SWITCH
Figure Battery-Referenced Shunt Resistor
08461-026
CONNECT
LOW-SIDE CURRENT SENSING
systems where low-side current sensing preferable, AD8209 provides simple, high accuracy, integrated solution. this configuration, AD8209 rejects ground noise offers high input output linearity, regardless differential input voltage.
INDUCTIVE LOAD CLAMP DIODE SWITCH OUTPUT
Figure Low-Side Switch
cases where high-side switch used control load current application, AD8209 used shown Figure recirculation current through freewheeling diode (clamp diode) monitored through shunt resistor. this configuration, common-mode voltage application drops below when switched off. AD8209 operates down providing accurate current measurement.
SWITCH OUTPUT
BATTERY SHUNT
AD8209
08461-029
BATTERY
SHUNT
AD8209
CONNECT
CLAMP DIODE INDUCTIVE LOAD
Figure Ground-Referenced Shunt Resistor
CONNECT
Figure High-Side Switch
Rev. Page
08461-027
AD8209
Current Loop Receiver
AD8209 also used current-sensing applications, such current loop receiver shown Figure such applications, relatively large shunt resistor degrade common-mode rejection. Adding resistor equal value impedance side input corrects this error.
used should equal minus parallel REXT example, with REXT (yielding composite gain V/V), optional offset nulling resistor
Gains Greater than
Connecting resistor from output buffer amplifier noninverting input, shown Figure increases gain. gain multiplied factor REXT/(REXT example, doubled REXT Overall gains high achievable this way. Note that accuracy gain becomes critically dependent resistor value high gains. addition, effective input offset voltage (which about times actual offset limits part high gain, dc-coupled applications.
OUTPUT
BATTERY
AD8209
OUTPUT
08461-030
CONNECT
GAIN
14REXT REXT 100k GAIN GAIN
Figure Current Loop Receiver
VDIFF
AD8209
REXT
GAIN ADJUSTMENT
default gain preamplifier buffer V/V, respectively, resulting composite gain V/V. With addition external resistor(s) trimmer(s), gain lowered, raised, finely calibrated.
REXT 100k
08461-032
Gains Less than
Because preamplifier output resistance external resistor connected from decreases gain following factor (see Figure 29): REXT/(100 REXT)
CONNECT
Figure Adjusting Gains Greater than
GAIN TRIM
Figure shows method incremental gain trimming using trim potentiometer external resistor, REXT. following approximation useful small gain ranges: REXT)% example, using this equation, adjustment range REXT ±10% REXT
OUTPUT
GAIN
VDIFF
AD8209
14REXT REXT 100k GAIN GAIN
REXT 100k
OUTPUT
REXT
VDIFF
08461-031
AD8209
CONNECT
Figure Adjusting Gains Less than
overall bandwidth unaffected changes gain using this method, although there small offset voltage imbalance source resistances input buffer. many cases, this ignored, desired, offset voltage nulled inserting resistor series with resistor
REXT
GAIN TRIM
08461-033
CONNECT
Figure Incremental Gain Trimming
Rev. Page
AD8209
Internal Signal Overload Considerations
When configuring gain values other than maximum input voltage with respect supply voltage ground must considered because either preamplifier output buffer reaches full-scale output with large differential input voltages. input AD8209 limited 0.1) overall gains because preamplifier, with fixed gain V/V, reaches full-scale output before output buffer. gains greater than swing buffer output reaches full scale first then limits AD8209 input 0.1) where overall gain. gain raised using resistor, shown Figure corner frequency lowered same factor gain raised. Therefore, using resistor (for which gain would doubled), results corner frequency scaled 0.796 (0.039 corner frequency).
OUTPUT
VDIFF
AD8209
LOW-PASS FILTERING
many transducer applications, necessary filter signal remove spurious high frequency components, including noise, extract mean value fluctuating signal with peakto-average ratio (PAR) greater than unity. example, full-wave rectified sinusoid 1.57, raised cosine half-wave sinusoid 3.14. Signals with large spikes have PARs more. When implementing filter, should considered that output AD8209 preamplifier (A1) does clip before otherwise, nonlinearity would averaged appear error output. avoid this error, both amplifiers should clip same time. This condition achieved when greater than gain second amplifier default configuration). example, expected, gain should increased Low-pass filters implemented several ways using features provided AD8209. simplest case, single-pole filter dB/decade) formed when output connected input internal resistor tying adding capacitor from this node ground, shown Figure resistor added across capacitor lower gain, corner frequency increases; therefore, gain should calculated using parallel resistor
40log (f2/f1)
fC(Hz) 1/C(µF)
255k
08461-035
CONNECT
Figure Two-Pole, Low-Pass Filter
two-pole filter with roll-off dB/decade implemented using connections shown Figure This configuration Sallen-Key form based amplifier. useful remember that two-pole filter with corner frequency single-pole filter with corner frequency have same attenuation, that (f2/f1), shown Figure Using standard resistor value shown Figure capacitors equal values, corner frequency conveniently scaled (0.05 corner frequency). maximal flat response occurs when resistor lowered scaling corner frequency 1.145 output offset raised approximately (equivalent input pins).
FREQUENCY
ATTENUATION
40dB/DECADE 20dB/DECADE
OUTPUT
VDIFF
FARADS
f22/f1
Figure Comparative Responses Single-Pole Two-Pole Low-Pass Filters
08461-034
CONNECT
Figure Single-Pole, Low-Pass Filter Using Internal Resistor
Rev. Page
08461-036
AD8209
2C10
1-POLE FILTER, CORNER 2-POLE FILTER, CORNER HAVE SAME ATTENUATION -40log (f2/f1) FREQUENCY f22/f1
AD8209
HIGH LINE CURRENT SENSING WITH GAIN ADJUSTMENT
circuit shown Figure similar Figure includes gain adjustment low-pass filtering.
INDUCTIVE LOAD
diode regulates common-mode potential applied device. example, battery spike result applied common-mode potential 21.5 input devices. produce full-scale output gain used, adjustable absorb tolerance shunt. There sufficient headroom allow overrange roughly triangular voltage across sense resistor averaged single-pole, low-pass filter that with corner frequency which provides about attenuation higher rate attenuation obtained using two-pole filter with corner frequency shown Figure Although this circuit uses separate capacitors, total capacitance less than half what needed single-pole filter.
08461-037
CLAMP DIODE
OUTPUT 4V/AMP
BATTERY
133k SHUNT
AD8209
SWITCH VOS/IB NULL CONNECT CALIBRATION RANGE fC(Hz) 0.767Hz/C(µF) (0.22µF 3.6Hz)
Figure High Line Current-Sensor Interface; Gain V/V, Single-Pole, Low-Pass Filter
CLAMP DIODE
INDUCTIVE LOAD
OUTPUT 432k
power device that either controls current load. average current proportional duty cycle input pulse sensed small-value resistor. average differential voltage across shunt typically although peak value higher amount that depends inductance load control frequency. commonmode voltage, other hand, extends from roughly above ground condition about above battery voltage condition. conduction clamping
BATTERY
SHUNT
AD8209
SWITCH CONNECT
Figure Two-Pole Low-Pass Filter
Rev. Page
08461-038
fC(Hz) =1/C(µF) (0.05µF 20Hz)
AD8209 OUTLINE DIMENSIONS
3.20 3.00 2.80
3.20 3.00 2.80 IDENTIFIER
5.15 4.90 4.65
0.65 0.95 0.85 0.75 0.15 0.05 COPLANARITY 0.10 0.40 0.25 1.10 0.80 0.55 0.40
100709-B
0.23 0.09
COMPLIANT JEDEC STANDARDS MO-187-AA
Figure 8-Lead Mini Small Outline Package [MSOP] (RM-8) Dimensions shown millimeters
ORDERING GUIDE
Model AD8209WBRMZ1 AD8209WBRMZ-R71 AD8209WBRMZ-RL1
Temperature Package -40°C +125°C -40°C +125°C -40°C +125°C
Package Description 8-Lead Mini Small Outline Package (MSOP) 8-Lead Mini Small Outline Package (MSOP) 8-Lead Mini Small Outline Package (MSOP)
Package Option RM-8 RM-8 RM-8
Branding
RoHS Compliant Part.
Rev. Page
AD8209 NOTES
©2009 Analog Devices, Inc. rights reserved. Trademarks registered trademarks property their respective owners. D08461-0-10/09(0)
Rev. Page
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