Dual, High Voltage Current Shunt Monitor AD8213 ±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 10-lead MSOP: −40°C to +125°C Excellent ac and dc performance 3 μV/°C typical offset drift −10 ppm/°C typical gain drift 120 dB typical CMRR at dc APPLICATIONS FUNCTIONAL BLOCK DIAGRAM –IN2 +IN2 +IN1 A2 –IN1 A1 PROPRIETARY OFFSET CIRCUITRY V+ PROPRIETARY OFFSET CIRCUITRY OUT2 OUT1 G = +20 G = +20 AD8213 CF2 GND CF1 06639-001 FEATURES 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 The AD8213 is a dual-channel, precision current sense amplifier. It features a set gain of 20 V/V, with a maximum ±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 AD8213 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 throughout the input differential voltage range of 0 mV to 250 mV, regardless of the common-mode voltage present. The AD8213 also features additional pins that allow the user to low-pass filter the input signal before amplifying, via an external capacitor to ground. The AD8213 has an operating temperature range of −40ºC to +125ºC and is offered in a small 10-lead MSOP package. 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. 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 Specifications..................................................................................... 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 5/07—Revision 0: Initial Version Rev. 0 | Page 2 of 16 AD8213 SPECIFICATIONS TOPR = operating temperature range, VS = 5 V, RL = 25 kΩ (RL is the output load resistor), unless otherwise noted. Table 1. Parameter GAIN Initial Accuracy Accuracy Over Temperature Gain vs. Temperature VOLTAGE OFFSET Offset Voltage (RTI) Over Temperature (RTI) Offset Drift INPUT Input Impedance Differential Common Mode Common-Mode Input Voltage Range Differential Input Voltage Range Common-Mode Rejection OUTPUT Output Voltage Range Low Output Voltage Range High Output Impedance FILTER RESISTOR DYNAMIC RESPONSE Small Signal −3 dB Bandwidth Slew Rate NOISE 0.1 Hz to 10 Hz, RTI Spectral Density, 1 kHz, RTI POWER SUPPLY Operating Range Quiescent Current Over Temperature Power Supply Rejection Ratio TEMPERATURE RANGE For Specified Performance 1 Min AD8213 Typ Max Unit Conditions ±0.5 −25 V/V % % ppm/°C VO ≥ 0.1 V dc TOPR ±1 ±2.2 ±12 mV mV μV/°C 25°C TOPR TOPR +65 250 120 90 kΩ MΩ kΩ V mV dB dB V common mode > 5 V V common mode < 5 V Common mode continuous Differential input voltage TOPR, f = DC, VCM > 5 V (see Figure 5) TOPR, f = DC, VCM < 5 V (see Figure 5) 0.05 4.95 2 20 V V Ω kΩ CF access to resistor for low-pass filter 500 4.5 2.7 kHz V/μs V/μs COUT = 20 pF, no filter capacitor (CF) COUT = 20 pF, CF = 20 pF 7 70 μV p-p nV/√Hz 20 ±0.25 0 −10 5 5 3.5 −2 100 80 0.1 18 4.5 2.5 4.9 22 5.5 3.75 76 −40 V mA VCM > 5 V, per amplifier 1 , total supply current for two channels dB +125 °C 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. 0 | Page 3 of 16 AD8213 ABSOLUTE MAXIMUM RATINGS Table 2. Parameter Supply Voltage Continuous Input Voltage Reverse Supply Voltage HBM (Human Body Model) ESD Rating CDM (Charged Device Model) ESD Rating Operating Temperature Range Storage Temperature Range Output Short-Circuit Duration Rating 12.5 V −3 V to +68 V −0.3 V ±4000 V ±1000 V −40°C to +125°C −65°C to +150°C 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 Rev. 0 | Page 4 of 16 AD8213 1 10 2 9 –IN2 1 10 –IN1 AD8213 9 +IN1 TOP VIEW (Not to Scale) 8 V+ 7 OUT1 6 CF1 +IN2 2 3 8 GND 3 OUT2 4 CF2 5 Figure 3. Pin Configuration 7 6 5 06639-002 4 Figure 2. Metallization Diagram Table 3. Pin Function Descriptions Pin No. 1 2 3 4 5 6 7 8 9 10 Mnemonic −IN2 +IN2 GND OUT2 CF2 CF1 OUT1 V+ +IN1 −IN1 X −401 −401 −401 −394 −448 448 394 401 401 401 Y 677 510 −53 −500 −768 −768 −500 −61 510 677 Description Inverting input of the second channel. Noninverting input of the second channel. Ground. Output of the second channel. Low-pass filter pin for the second channel. Low-pass filter pin for the first channel. Output of the first channel. Supply. Noninverting input of the first channel. Inverting input of the first channel. Rev. 0 | Page 5 of 16 06639-003 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS AD8213 TYPICAL PERFORMANCE CHARACTERISTICS 0.8 0.7 40 35 30 25 20 0 –0.1 –0.2 –0.3 –0.4 –0.5 –0.6 –0.7 –20 0 20 40 60 80 100 120 TEMPERATURE (°C) –40 10k 06639-104 –0.8 –40 10M Figure 7. Typical Small Signal Bandwidth (VOUT = 200 mV p-p) 10 COMMON-MODE VOLTAGE > 5V 110 100 90 COMMON-MODE VOLTAGE < 5V 80 70 60 100 1k 10k 100k 1M FREQUENCY (Hz) 8 7 6 5 4 3 2 1 0 –1 06639-005 50 10 9 DIFFERENTIAL INPUT VOLTAGE (mV) Figure 5. CMRR vs. Frequency Figure 8. Total Output Error vs. Differential Input Voltage 2500 –475 2000 –480 –485 INPUT BIAS CURRENT (nA) 1500 1000 500 0 –500 –1000 –1500 –490 –495 –500 +IN –505 –510 –515 –520 –525 –2000 –IN –530 –20 0 20 40 60 TEMPERATURE (°C) 80 100 120 06639-102 –2500 –40 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 250 –535 0 25 50 75 100 125 150 175 200 225 DIFFERENTIAL INPUT VOLTAGE (mV) Figure 9. Input Bias Current vs. Differential Input Voltage (VCM = 0 V) (Per Channel) Figure 6. Typical Gain Drift Rev. 0 | Page 6 of 16 250 06639-010 120 06639-013 OUTPUT ERROR (%) (% ERROR OF THE IDEAL OUTPUT VALUE) 130 CMRR (dB) 1M FREQUENCY (Hz) Figure 4. Typical Offset Drift GAIN ERROR (ppm) 100k 06639-008 15 10 5 0 –5 –10 –15 –20 –25 –30 –35 GAIN (dB) VOSI (mV) 0.6 0.5 0.4 0.3 0.2 0.1 AD8213 0.2 INPUT 100mV/DIV –0.2 OUTPUT –0.4 –0.6 OUTPUT 1V/DIV, CF = 20pF –0.8 1V/DIV, CF = 100pF –1.2 –5 5 15 25 35 45 55 65 INPUT COMMON-MODE VOLTAGE (V) 06639-011 –1.0 06639-015 INPUT BIAS CURRENT (mA) 0 TIME (2µs/DIV) Figure 10. Input Bias Current vs. Common-Mode Voltage (Per Input) Figure 13. Rise Time 7.0 6.5 200mV/DIV 5.5 5.0 INPUT 4.5 4.0 3.5 2V/DIV, CF = 20pF 3.0 2.5 2.0 OUTPUT –2 0 2 4 6 8 65 COMMON-MODE VOLTAGE (V) 06639-016 1.0 –4 06639-012 1.5 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, CF = 20pF OUTPUT OUTPUT OUTPUT TIME (2µs/DIV) 2V/DIV, CF = 20pF TIME (1µs/DIV) Figure 12. Fall Time Figure 15. Differential Overload Recovery (Rising) Rev. 0 | Page 7 of 16 06639-017 1V/DIV, CF = 100pF 06639-014 SUPPLY CURRENT (mA) 6.0 AD8213 0.01/DIV 10 9 8 7 6 5 4 3 2 1 0 –40 06639-105 TIME (5µs/DIV) 11 –20 0 20 40 60 80 100 120 140 TEMPERATURE (°C) Figure 16. Settling Time (Falling) 06639-021 MAXIMUM OUTPUT SOURCE CURRENT (mA) 12 2V/DIV Figure 19. Output Source Current vs. Temperature (Per Channel) 5.0 4.9 OUTPUT VOLTAGE RANGE (V) 4.8 2V/DIV 0.01/DIV 4.7 4.6 4.5 4.4 4.3 4.2 4.1 4.0 3.9 3.8 3.7 06639-106 3.5 TIME (5µs/DIV) Figure 20. Output Voltage Range vs. Output Source Current (Per Channel) 12 2.0 10 9 8 7 6 5 4 3 2 1 –20 0 20 40 60 80 100 120 TEMPERATURE (°C) 140 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0 0 1 2 3 4 5 6 7 OUTPUT SINK CURRENT (mA) Figure 18. Output Sink Current vs. Temperature (Per Channel) 8 9 10 06639-024 OUTPUT VOLTAGE RANGE FROM GND (V) 11 06639-020 MAXIMUM OUTPUT SINK CURRENT (mA) 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 7.5 OUTPUT SOURCE CURRENT (mA) Figure 17. Settling Time (Rising) 0 –40 0 06639-023 3.6 Figure 21. Output Voltage Range from GND vs. Output Sink Current (Per Channel) Rev. 0 | Page 8 of 16 AD8213 2100 TEMP = –40°C TEMP = +25°C TEMP = +125°C 1000 1800 1500 600 COUNT COUNT 800 400 1200 900 600 200 –10 –5 0 5 10 15 VOS (µV/°C) 0 –2.0 06639-006 0 –15 1200 800 600 400 200 –18 –15 –12 –9 –6 GAIN DRIFT (ppm/°C) –3 0 06639-101 COUNT 1000 –21 –0.5 0 0.5 1.0 Figure 24. Offset Distribution (mV) (VCM = 6 V) 1400 –24 –1.0 VOS (mV) Figure 22. Offset Drift Distribution (μV/°C) (Temperature Range = −40°C to +125°C) 0 –1.5 Figure 23. Gain Drift Distribution (ppm/°C) (Temperature Range = −40°C to +125°C) Rev. 0 | Page 9 of 16 1.5 2.0 06639-103 300 AD8213 THEORY OF OPERATION In typical applications, the AD8213 amplifies a small differential input voltage generated by the load current flowing through a shunt resistor. The AD8213 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 25 shows a simplified schematic of the AD8213. This current (IIN1) is converted back to a voltage via ROUT1. 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 The following explanation refers exclusively to Channel 1 of the AD8213, however, the same explanation applies to Channel 2. Prior to the buffer amplifier, a precision-trimmed 20 kΩ resistor is available to perform low-pass filtering of the input signal prior to the amplification stage. This means that the noise of the input signal is not amplified, but rejected, resulting in a more precise output signal that will directly interface with a converter. A capacitor from the CF1 pin to GND, will result in a low-pass filter with a corner frequency of VOUT1 = (ISHUNT1 × RSHUNT1) × 20 A load current flowing through the external shunt resistor produces a voltage at the input terminals of the AD8213. The input terminals are connected to Amplifier A1 by Resistor R1(1) and Resistor R1(2). The inverting terminal, which has very high input impedance is held to (VCM) – (ISHUNT × RSHUNT), since negligible current flows through Resistor R1(2). Amplifier A1 forces the noninverting input to the same potential. Therefore, the current that flows through Resistor R1(1), is equal to f −3dB = 1 2 π(20000 )C FILTER IIN1 = (ISHUNT1 × RSHUNT1)/R1(1) ISHUNT2 ISHUNT1 RSHUNT2 RSHUNT1 IIN1 R2 (2) R2 (1) R1 (1) A2 A1 PROPRIETARY OFFSET CIRCUITRY 20kΩ ROUT2 G = +20 V+ PROPRIETARY OFFSET CIRCUITRY Q1 Q2 20kΩ OUT2 = (ISHUNT2 × RSHUNT2 ) × 20 R1 (2) OUT1 = (ISHUNT1 × RSHUNT1 ) × 20 ROUT1 G = +20 AD8213 CF2 GND CF1 Figure 25. Simplified Schematic Rev. 0 | Page 10 of 16 06639-028 IIN2 AD8213 APPLICATION NOTES OUTPUT LINEARITY LOW-PASS FILTERING 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 AD8213 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 26 displays the input differential voltage versus the corresponding output voltage at different common modes. In typical applications, such as motor and solenoid current sensing, filtering the differential input signal of the AD8213 could be beneficial in reducing differential common-mode noise as well as transients and current ripples flowing through the input shunt resistor. Typically, such a filter can be implemented by adding a resistor in series with each input and a capacitor directly between the input pins. However, the AD8213 features a filter pin available after the input stage, but before the final amplification stage. The user can connect a capacitor to ground, making a low-pass filter with the internal precisiontrimmed 20 kΩ resistor. This means the no gain or CMRR errors are introduced by adding resistors at the input of the AD8213. Figure 27 shows the typical connection. 220 200 180 160 ISHUNT1 RSHUNT2 RSHUNT1 R2 (1) 120 R2 (2) R1 (1) R1 (2) VOUT @ VCM = 65V 100 A2 VOUT @ VCM = 0V 80 A1 PROPRIETARY OFFSET CIRCUITRY 60 40 20kΩ 20 V+ PROPRIETARY OFFSET CIRCUITRY 20kΩ IDEAL VOUT 0 1 2 3 4 5 6 7 VIN DIFFERENTIAL (mV) 8 9 10 G = +20 06639-029 0 AD8213 Figure 26. Gain Linearity Due to Differential and Common-Mode Voltage The AD8213 provides a correct output voltage, regardless of the common mode, when the input differential is at least 2 mV. This 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 in order to provide sufficient guardbands. The ability of the AD8213 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. G = +20 CF2 GND CAP2 CF1 CAP1 06639-030 VOUT (mV) 140 ISHUNT2 Figure 27. Filter Capacitor Connections The 3 dB frequency of this low-pass filter is calculated using the following formula: f −3dB = 1 2 π(20000 )C FILTER 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. 0 | Page 11 of 16 AD8213 APPLICATIONS INFORMATION OVERCURRENT DETECTION (<100ns) HIGH-SIDE CURRENT SENSE WITH A LOW-SIDE SWITCH 8 SHUNT +IN2 +IN1 9 3 GND 4 OUT2 5 CF2 CAP2 V+ 8 OUT1 7 CF1 6 4 5 6 7 8 OUT GND NC –IN AD8214 NC VREG +IN SHUNT 3 2 VS 1 SHUNT AD8213 LOAD 1 –IN2 –IN1 10 2 +IN2 +IN1 9 3 GND V+ 8 4 OUT2 OUT1 7 5 CF2 CF1 6 5V LOAD BATTERY 4 CAP2 SWITCH CAP1 CLAMP DIODE 5V CAP1 SHUNT BATTERY Figure 29. Battery Referenced Shunt Resistor LOW-SIDE CURRENT SENSING SWITCH 06639-031 SWITCH –IN1 10 2 3 06639-032 BATTERY AD8213 –IN2 2 OVERCURRENT DETECTION (<100ns) INDUCTIVE LOAD 1 +IN VREG NC Figure 28. Low-Side Switch HIGH-SIDE CURRENT SENSING In this configuration, the shunt resistor is referenced to the battery. High voltage will be 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 AD8213 produces a linear ground referenced analog output. An AD8214 can also be used 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. In systems where low-side current sensing is preferred, the AD8213 provides an integrated solution with great accuracy. Ground noise is rejected, CMRR is typical higher than 90 dB, and output linearity is not compromised, regardless of the input differential voltage. INDUCTIVE LOAD BATTERY Rev. 0 | Page 12 of 16 INDUCTIVE LOAD AD8213 CLAMP DIODE 1 –IN2 –IN1 10 CLAMP DIODE SWITCH 2 +IN2 +IN1 9 SWITCH 3 GND 4 OUT2 5 CF2 SHUNT V+ 8 OUT1 7 CF1 6 5V BATTERY SHUNT 06639-033 CLAMP DIODE 5 VS 1 SWITCH INDUCTIVE LOAD 6 NC GND OUT AD8214 BATTERY 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 28). 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. 7 –IN Figure 30. Ground Referenced Shunt Resistor AD8213 ICHARGE BIDIRECTIONAL CURRENT SENSING The AD8213 can also be configured to sense current in both directions at the inputs. This configuration is useful in charge/ discharge applications. A typical connection diagram is shown in Figure 31. In this mode Channel 1 monitors ILOAD and Channel 2 monitors ICHARGE. ILOAD RSHUNT BATTERY +IN LOAD CHARGER –IN V+ ICHARGE ILOAD BATTERY AD8210 0.1µF RSHUNT LOAD VREF 1 CHARGER G = +20 AD8213 –IN2 –IN1 10 2 +IN2 +IN1 9 3 GND V+ 8 4 OUT2 OUT1 7 5 CF2 VREF 2 GND 6 CF1 06639-034 CF2 CF1 5V 06639-035 1 OUTPUT 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 bidirectional capability. The typical connection diagram for the AD8210 in bidirectional applications is shown in Figure 32. Rev. 0 | Page 13 of 16 AD8213 OUTLINE DIMENSIONS 3.10 3.00 2.90 10 3.10 3.00 2.90 1 6 5 5.15 4.90 4.65 PIN 1 0.50 BSC 0.95 0.85 0.75 1.10 MAX 0.15 0.05 0.33 0.17 SEATING PLANE 0.23 0.08 8° 0° 0.80 0.60 0.40 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 AD8213YRMZ 1 AD8213YRMZ-RL1 AD8213YRMZ-RL71 1 Temperature Range −40°C to +125°C −40°C to +125°C −40°C to +125°C Package Description 10-Lead MSOP 10-Lead MSOP, 13” Tape and Reel 10-Lead MSOP, 7” Tape and Reel Z = RoHS Compliant Part. Rev. 0 | Page 14 of 16 Package Option RM-10 RM-10 RM-10 Branding HOU HOU HOU AD8213 NOTES Rev. 0 | Page 15 of 16 AD8213 NOTES ©2007 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D06639-0-5/07(0) Rev. 0 | Page 16 of 16