ANALOG DEVICES AD8213

Dual, High Voltage Current Shunt Monitor AD8213 FEATURES FUNCTIONAL BLOCK DIAGRAM –IN2 +IN2 +IN1 –IN1 ±4000 V HBM ESD High common-mode voltage range −2 V to +65 V operating −3 V to +68 V survival A2 A1 V+ Buffered output voltage PROPRIETARY PROPRIETARY Wide operating temperature range OFFSET OFFSET CIRCUITRY CIRCUITRY 10-lead MSOP: −40°C to +125°C Excellent ac and dc performance OUT2 OUT1 3 μV/°C typical offset drift G = +20 G = +20 −10 ppm/°C typical gain drift 120 dB typical CMRR at dc AD8213 CF2 GND CF1 APPLICATIONS Figure 1. High-side current sensing Motor controls Transmission controls Diesel injection controls Engine management Suspension controls Vehicle dynamic controls DC-to-DC converters GENERAL DESCRIPTION Special circuitry is devoted to output linearity being maintained The AD8213 is a dual-channel, precision current sense amplifier. It throughout the input differential voltage range of 0 mV to 250 mV, features a set gain of 20 V/V, with a maximum ±0.5% gain error regardless of the common-mode voltage present. The AD8213 over the entire temperature range. The buffered output voltage directly interfaces with any typical converter. Excellent common- also features additional pins that allow the user to low-pass filter mode rejection from −2 V to +65 V, is independent of the 5 V the input signal before amplifying, via an external capacitor to supply. The AD8213 performs unidirectional current measure- ground. The AD8213 has an operating temperature range of −40ºC to +125ºC and is offered in a small 10-lead MSOP package. ments across a shunt resistor in a variety of industrial and automotive applications, such as motor control, solenoid control, or battery management. Rev. A 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 One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 www.analog.com license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Fax: 781.461.3113 ©2007–2009 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. 06639-001 AD8213 TABLE OF CONTENTS Features .............................................................................................. 1 Application Notes ........................................................................... 11 Applications ....................................................................................... 1 Output Linearity ......................................................................... 11 Functional Block Diagram .............................................................. 1 Low-Pass Filtering ...................................................................... 11 General Description ......................................................................... 1 Applications Information .............................................................. 12 Revision History ............................................................................... 2 High-Side Current Sense with a Low-Side Switch ................. 12 Specif ica t ions ..................................................................................... 3 High-Side Current Sensing ....................................................... 12 Absolute Maximum Ratings ............................................................ 4 Low-Side Current Sensing ........................................................ 12 ESD Caution .................................................................................. 4 Bidirectional Current Sensing .................................................. 13 Pin Configuration and Function Descriptions ............................. 5 Outline Dimensions ....................................................................... 14 Typical Performance Characteristics ............................................. 6 Ordering Guide .......................................................................... 14 Theory of Operation ...................................................................... 10 REVISION HISTORY 5/09—Rev. 0 to Rev. A Changes to Ordering Guide .......................................................... 14 5/07—Revision 0: Initial Version Rev. A | Page 2 of 16 AD8213 SPECIFICATIONS T = operating temperature range, V = 5 V, R = 25 kΩ (R is the output load resistor), unless otherwise noted. OPR S L L Table 1. AD8213 Parameter Min Typ Max Unit Conditions GAIN Initial 20 V/V Accuracy ±0.25 % VO ≥ 0.1 V dc Accuracy Over Temperature ±0.5 % T OPR Gain vs. Temperature 0 −10 −25 ppm/°C VOLTAGE OFFSET Offset Voltage (RTI) ±1 mV 25°C Over Temperature (RTI) ±2.2 mV TOPR Offset Drift ±12 μV/°C TOPR INPUT Input Impedance Differential 5 kΩ Common Mode 5 MΩ V common mode > 5 V 3.5 kΩ V common mode < 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 T , f = DC, V > 5 V (see Figure 5) OPR CM 80 90 dB TOPR, 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 FILTER RESISTOR 18 20 22 kΩ CF access to resistor for low-pass filter DYNAMIC RESPONSE Small Signal −3 dB Bandwidth 500 kHz Slew Rate 4.5 V/μs COUT = 20 pF, no filter capacitor (CF) COUT = 20 pF, CF = 20 pF 2.7 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 1 Quiescent Current Over Temperature 2.5 3.75 mA V > 5 V, per amplifier , total supply CM current for two channels Power Supply Rejection Ratio 76 dB TEMPERATURE RANGE For Specified Performance −40 +125 °C 1 When the input common mode is less than 5 V, the supply current increases. This can be calculated by IS = −0.52(VCM) + 4.9 (see Figure 11). Rev. A | Page 3 of 16 AD8213 ABSOLUTE MAXIMUM RATINGS Table 2. Stresses above those listed under Absolute Maximum Ratings Parameter Rating may cause permanent damage to the device. This is a stress Supply Voltage 12.5 V rating only; functional operation of the device at these or any Continuous Input Voltage −3 V to +68 V other conditions above those indicated in the operational Reverse Supply Voltage −0.3 V section of this specification is not implied. Exposure to absolute HBM (Human Body Model) ESD Rating ±4000 V maximum rating conditions for extended periods may affect CDM (Charged Device Model) ESD Rating ±1000 V device reliability. Operating Temperature Range −40°C to +125°C Storage Temperature Range −65°C to +150°C Output Short-Circuit Duration Indefinite ESD CAUTION Rev. A | Page 4 of 16 AD8213 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS 1 10 2 9 –IN2 1 10 –IN1 +IN2 2 9 +IN1 AD8213 38 GND 3 8 V+ TOP VIEW (Not to Scale) OUT2 4 7 OUT1 CF2 5 6 CF1 47 Figure 3. Pin Configuration 5 6 Figure 2. Metallization Diagram Table 3. Pin Function Descriptions Pin No. Mnemonic X Y Description 1 −IN2 −401 677 Inverting input of the second channel. 2 +IN2 −401 510 Noninverting input of the second channel. 3 GND −401 −53 Ground. 4 OUT2 −394 −500 Output of the second channel. 5 CF2 −448 −768 Low-pass filter pin for the second channel. 6 CF1 448 −768 Low-pass filter pin for the first channel. 7 OUT1 394 −500 Output of the first channel. 8 V+ 401 −61 Supply. 9 +IN1 401 510 Noninverting input of the first channel. 10 −IN1 401 677 Inverting input of the first channel. Rev. A | Page 5 of 16 06639-002 06639-003 AD8213 TYPICAL PERFORMANCE CHARACTERISTICS 0.8 40 0.7 35 0.6 30 0.5 25 0.4 20 0.3 15 0.2 10 0.1 5 0 0 –0.1 –5 –0.2 –10 –0.3 –15 –0.4 –20 –0.5 –25 –0.6 –30 –0.7 –35 –0.8 –40 –40 –20 0 20406080 100 120 10k 100k 1M 10M TEMPERATURE (°C) FREQUENCY (Hz) Figure 4. Typical Offset Drift Figure 7. Typical Small Signal Bandwidth (V = 200 mV p-p) OUT 10 130 COMMON-MODE VOLTAGE > 5V 9 120 8 110 7 6 100 5 COMMON-MODE VOLTAGE < 5V 90 4 80 3 2 70 1 60 0 –1 50 02 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 9550 10 100 1k 10k 100k 1M DIFFERENTIAL INPUT VOLTAGE (mV) FREQUENCY (Hz) Figure 5. CMRR vs. Frequency Figure 8. Total Output Error vs. Differential Input Voltage 2500 –475 –480 2000 –485 1500 –490 1000 –495 500 –500 +IN 0 –505 –510 –500 –515 –1000 –520 –1500 –525 –IN –2000 –530 –2500 –535 –40 –20 0 20406080 100 120 02 25 50 75 100 125 150 175 200 22550 TEMPERATURE (°C) DIFFERENTIAL INPUT VOLTAGE (mV) Figure 6. Typical Gain Drift Figure 9. Input Bias Current vs. Differential Input Voltage (V = 0 V) (Per Channel) CM Rev. A | Page 6 of 16 GAIN ERROR (ppm) V (mV) OSI CMRR (dB) 06639-005 06639-102 06639-104 OUTPUT ERROR (%) INPUT BIAS CURRENT (nA) GAIN (dB) (% ERROR OF THE IDEAL OUTPUT VALUE) 06639-010 06639-008 06639-013 AD8213 0.2 INPUT 0 100mV/DIV –0.2 OUTPUT –0.4 –0.6 OUTPUT 1V/DIV, C = 20pF F –0.8 1V/DIV, C = 100pF –1.0 F –1.2 –5 5 15 25 35 45 55 65 INPUT COMMON-MODE VOLTAGE (V) TIME (2µs/DIV) Figure 10. Input Bias Current vs. Common-Mode Voltage Figure 13. Rise Time (Per Input) 7.0 6.5 200mV/DIV 6.0 5.5 5.0 INPUT 4.5 4.0 3.5 2V/DIV, C = 20pF F 3.0 2.5 2.0 OUTPUT 1.5 1.0 –4 –2 0 2 4 6 8 65 COMMON-MODE VOLTAGE (V) TIME (1µs/DIV) Figure 11. Supply Current vs. Common-Mode Voltage Figure 14. Differential Overload Recovery (Falling) 100mV/DIV INPUT INPUT 200mV/DIV 1V/DIV, C = 20pF F OUTPUT OUTPUT 1V/DIV, C = 100pF F OUTPUT 2V/DIV, C = 20pF F TIME (2µs/DIV) TIME (1µs/DIV) Figure 12. Fall Time Figure 15. Differential Overload Recovery (Rising) Rev. A | Page 7 of 16 SUPPLY CURRENT (mA) INPUT BIAS CURRENT (mA) 06639-014 06639-012 06639-011 06639-017 06639-016 06639-015 AD8213 12 2V/DIV 11 10 9 8 7 6 0.01/DIV 5 4 3 2 1 0 –40 –20 0 20 40 60 80 100 120 140 TIME (5µs/DIV) TEMPERATURE (°C) Figure 16. Settling Time (Falling) Figure 19. Output Source Current vs. Temperature (Per Channel) 5.0 4.9 4.8 4.7 4.6 2V/DIV 4.5 4.4 4.3 4.2 0.01/DIV 4.1 4.0 3.9 3.8 3.7 3.6 3.5 07 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0.5 TIME (5µs/DIV) OUTPUT SOURCE CURRENT (mA) Figure 17. Settling Time (Rising) Figure 20. Output Voltage Range vs. Output Source Current (Per Channel) 12 2.0 11 1.8 10 1.6 9 1.4 8 1.2 7 6 1.0 5 0.8 4 0.6 3 0.4 2 0.2 1 0 0 –40 –20 0 20 40 60 80 100 120 140 01 1 2 3 4 5 6 7 8 90 TEMPERATURE (°C) OUTPUT SINK CURRENT (mA) Figure 18. Output Sink Current vs. Temperature Figure 21. Output Voltage Range from GND vs. Output Sink Current (Per Channel) (Per Channel) Rev. A | Page 8 of 16 MAXIMUM OUTPUT SINK CURRENT (mA) 06639-106 06639-105 06639-020 OUTPUT VOLTAGE RANGE (V) OUTPUT VOLTAGE RANGE FROM GND (V) MAXIMUM OUTPUT SOURCE CURRENT (mA) 06639-021 06639-024 06639-023 AD8213 2100 TEMP = –40°C 1000 TEMP = +25°C TEMP = +125°C 1800 800 1500 600 1200 900 400 600 200 300 0 0 –15 –10 –5 0 5 10 15 –2.0 –1.5 –1.0 –0.5 0 0.5 1.0 1.5 2.0 V (µV/°C) OS V (mV) OS Figure 24. Offset Distribution (mV) Figure 22. Offset Drift Distribution (μV/°C) (VCM = 6 V) (Temperature Range = −40°C to +125°C) 1400 1200 1000 800 600 400 200 0 –24 –21 –18 –15 –12 –9 –6 –3 0 GAIN DRIFT (ppm/°C) Figure 23. Gain Drift Distribution (ppm/°C) (Temperature Range = −40°C to +125°C) Rev. A | Page 9 of 16 COUNT COUNT 06639-006 06639-101 COUNT 06639-103 AD8213 THEORY OF OPERATION In typical applications, the AD8213 amplifies a small differential This current (IIN1) is converted back to a voltage via ROUT1. The input voltage generated by the load current flowing through a output buffer amplifier has a gain of 20 V/V, and offers excellent shunt resistor. The AD8213 rejects high common-mode accuracy as the internal gain setting resistors are precision voltages (up to 65 V) and provides a ground referenced, buffered trimmed to within 0.01% matching. The resulting output output that interfaces with an analog-to-digital converter (ADC). voltage is equal to Figure 25 shows a simplified schematic of the AD8213. V = (I × R ) × 20 OUT1 SHUNT1 SHUNT1 The following explanation refers exclusively to Channel 1 of the Prior to the buffer amplifier, a precision-trimmed 20 kΩ resistor AD8213, however, the same explanation applies to Channel 2. is available to perform low-pass filtering of the input signal A load current flowing through the external shunt resistor prior to the amplification stage. This means that the noise of the produces a voltage at the input terminals of the AD8213. The input signal is not amplified, but rejected, resulting in a more input terminals are connected to Amplifier A1 by Resistor R1(1) precise output signal that will directly interface with a converter. and Resistor R1(2). The inverting terminal, which has very high A capacitor from the CF1 pin to GND, will result in a low-pass input impedance is held to (V ) – (I × R ), since filter with a corner frequency of CM SHUNT SHUNT negligible current flows through Resistor R1 . Amplifier A1 (2) 1 f = forces the noninverting input to the same potential. Therefore, −3dB 2π() 20000 C FILTER the current that flows through Resistor R1 , is equal to (1) IIN1 = (ISHUNT1 × RSHUNT1)/R1(1) I I SHUNT2 SHUNT1 R R SHUNT2 SHUNT1 I I IN2 IN1 R2 R2 R1 R1 (1) (2) (1) (2) A2 A1 V+ PROPRIETARY PROPRIETARY OFFSET OFFSET CIRCUITRY CIRCUITRY Q2 Q1 20kΩ 20kΩ OUT2 = (I × R ) × 20 × R ) × 20 OUT1 = (I SHUNT2 SHUNT2 SHUNT1 SHUNT1 R R G = +20 OUT2 OUT1 G = +20 AD8213 CF2 GND CF1 Figure 25. Simplified Schematic Rev. A | Page 10 of 16 06639-028 AD8213 APPLICATION NOTES OUTPUT LINEARITY LOW-PASS FILTERING In all current sensing applications, and especially in automotive In typical applications, such as motor and solenoid current and industrial environments where the common-mode voltage sensing, filtering the differential input signal of the AD8213 can vary significantly, it is important that the current sensor could be beneficial in reducing differential common-mode maintain the specified output linearity, regardless of the input noise as well as transients and current ripples flowing through differential or common-mode voltage. The AD8213 contains the input shunt resistor. Typically, such a filter can be imple- specific circuitry on the input stage, which ensures that even mented by adding a resistor in series with each input and a when the differential input voltage is very small, and the capacitor directly between the input pins. However, the AD8213 common-mode voltage is also low (below the 5 V supply), the features a filter pin available after the input stage, but before the input to output linearity is maintained. Figure 26 displays the final amplification stage. The user can connect a capacitor to input differential voltage versus the corresponding output ground, making a low-pass filter with the internal precision- voltage at different common modes. trimmed 20 kΩ resistor. This means the no gain or CMRR 220 errors are introduced by adding resistors at the input of the AD8213. Figure 27 shows the typical connection. 200 I I 180 SHUNT2 SHUNT1 160 R R SHUNT2 SHUNT1 140 R2 R2 R1 R1 (1) (2) (1) (2) 120 V @ V = 65V OUT CM 100 A2 A1 V @ V = 0V OUT CM V+ 80 60 PROPRIETARY PROPRIETARY OFFSET OFFSET CIRCUITRY CIRCUITRY 40 20 20kΩ 20kΩ IDEAL V OUT 0 G = +20 G = +20 0123456789 10 V DIFFERENTIAL (mV) IN AD8213 Figure 26. Gain Linearity Due to Differential and Common-Mode Voltage CF2 GND CF1 The AD8213 provides a correct output voltage, regardless of the CAP2 CAP1 common mode, when the input differential is at least 2 mV. This is due to the voltage range of the output amplifier that can Figure 27. Filter Capacitor Connections go as low as 33 mV typical. The specified minimum output amplifier voltage is 100 mV in order to provide sufficient The 3 dB frequency of this low-pass filter is calculated using the guardbands. The ability of the AD8213 to work with very small following formula: differential inputs regardless of the common-mode voltage, 1 f = allows for more dynamic range, accuracy, and flexibility in any −3dB 2π() 20000 C FILTER current sensing application. It is recommended that in order to prevent output chatter due to noise potentially entering through the filter pin and coupling to the output, a capacitor is always placed from the filter pin to GND. This can be a ≈20 pF capacitor in cases when all of the bandwidth of the AD8213 is needed in the application. Rev. A | Page 11 of 16 V (mV) OUT 06639-029 06639-030 AD8213 APPLICATIONS INFORMATION OVERCURRENT HIGH-SIDE CURRENT SENSE WITH A LOW-SIDE DETECTION (<100ns) SWITCH 8 7 6 5 –IN NC GND OUT In such load control configurations, the PWM controlled switch AD8214 is ground referenced. An inductive load (solenoid) is tied to a V +IN V NC S REG 1 2 3 4 power supply. A resistive shunt is placed between the switch and the load (see Figure 28). An advantage of placing the shunt on OVERCURRENT the high side is that the entire current, including the recircu- DETECTION (<100ns) lation current, can be measured, because the shunt remains in 5 6 7 8 the loop when the switch is off. In addition, diagnostics can be OUT GND NC –IN enhanced because shorts to ground can be detected with the AD8214 NC V +IN V REG S shunt on the high side. In this circuit configuration, when the 4 3 2 1 switch is closed, the common-mode voltage moves down to SHUNT SHUNT near the negative rail. When the switch is opened, the voltage AD8213 1 –IN2 –IN1 10 reversal across the inductive load causes the common-mode 2 +IN2 +IN1 9 LOAD 5V LOAD voltage to be held one diode drop above the battery by the 3 GND V+ 8 clamp diode. 4 OUT2 OUT1 7 5 CF2 CF1 6 SWITCH SWITCH INDUCTIVE INDUCTIVE LOAD AD8213 LOAD CAP2 CAP1 CLAMP CLAMP 1 –IN2 –IN1 10 DIODE DIODE 2 +IN2 +IN1 9 5V SHUNT SHUNT BATTERY BATTERY 3 GND V+ 8 Figure 29. Battery Referenced Shunt Resistor 4 OUT2 OUT1 7 5 6 CF2 CF1 LOW-SIDE CURRENT SENSING SWITCH SWITCH CAP2 CAP1 In systems where low-side current sensing is preferred, the AD8213 provides an integrated solution with great accuracy. Figure 28. Low-Side Switch Ground noise is rejected, CMRR is typical higher than 90 dB, and output linearity is not compromised, regardless of the input HIGH-SIDE CURRENT SENSING differential voltage. In this configuration, the shunt resistor is referenced to the battery. High voltage will be present at the inputs of the current INDUCTIVE INDUCTIVE LOAD LOAD AD8213 sense amplifier. In this mode, the recirculation current is again CLAMP CLAMP 1 –IN2 –IN1 10 DIODE DIODE 2 9 measured and shorts to ground can be detected. When the SWITCH +IN2 +IN1 SWITCH 5V BATTERY BATTERY 3 GND V+ 8 shunt is battery referenced the AD8213 produces a linear 4 OUT2 OUT1 7 5 CF2 CF1 6 ground referenced analog output. An AD8214 can also be used SHUNT SHUNT to provide an overcurrent detection signal in as little as 100 ns. This feature will be useful in high current systems, where fast shutdown in overcurrent conditions is essential. Figure 30. Ground Referenced Shunt Resistor Rev. A | Page 12 of 16 06639-031 BATTERY BATTERY 06639-033 06639-032 AD8213 I CHARGE BIDIRECTIONAL CURRENT SENSING I LOAD The AD8213 can also be configured to sense current in both R directions at the inputs. This configuration is useful in charge/ SHUNT LOAD CHARGER BATTERY discharge applications. A typical connection diagram is shown +IN –IN in Figure 31. In this mode Channel 1 monitors I and LOAD Channel 2 monitors I . CHARGE V+ I CHARGE I LOAD AD8210 0.1µF R SHUNT V 1 REF LOAD CHARGER BATTERY OUTPUT G = +20 AD8213 1 –IN2 –IN1 10 2 +IN2 +IN1 9 5V V 2 REF 3 GND V+ 8 GND 4 OUT2 OUT1 7 5 CF2 CF1 6 CF2 CF1 Figure 32. AD8210 in Bidirectional Applications Figure 31. Bidirectional Current Sensing For applications requiring a bidirectional current measurement, an optimal solution could be to use a single channel device, which offers the same functionality as the previous circuit. The AD8210 is a single channel current sensor featuring bidirec- tional capability. The typical connection diagram for the AD8210 in bidirectional applications is shown in Figure 32. Rev. A | Page 13 of 16 06639-034 06639-035 AD8213 OUTLINE DIMENSIONS 3.10 3.00 2.90 10 6 5.15 3.10 4.90 3.00 4.65 2.90 1 5 PIN 1 0.50 BSC 0.95 0.85 1.10 MAX 0.75 0.80 8° 0.15 0.60 0.33 SEATING 0.23 0° 0.05 PLANE 0.40 0.17 0.08 COPLANARITY 0.10 COMPLIANT TO JEDEC STANDARDS MO-187-BA Figure 33. 10-Lead Mini Small Outline Package [MSOP] (RM-10) Dimensions shown in millimeters ORDERING GUIDE Model Temperature Range Package Description Package Option Branding 1 AD8213YRMZ −40°C to +125°C 10-Lead MSOP RM-10 H0U 1 AD8213YRMZ-RL −40°C to +125°C 10-Lead MSOP, 13” Tape and Reel RM-10 H0U 1 AD8213YRMZ-RL7 −40°C to +125°C 10-Lead MSOP, 7” Tape and Reel RM-10 H0U 1 AD8213WYRMZ −40°C to +125°C 10-Lead MSOP RM-10 Y2B 1 AD8213WYRMZ-RL −40°C to +125°C 10-Lead MSOP, 13” Tape and Reel RM-10 Y2B 1 AD8213WYRMZ-R7 −40°C to +125°C 10-Lead MSOP, 7” Tape and Reel RM-10 Y2B 1 Z = RoHS Compliant Part. Rev. A | Page 14 of 16 AD8213 NOTES Rev. A | Page 15 of 16 AD8213 NOTES ©2007–2009 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D06639-0-5/09(A) Rev. A | Page 16 of 16