AD8209AWBRMZ-RL

High Voltage, Precision Difference Amplifier AD8209A Data Sheet FUNCTIONAL BLOCK DIAGRAM ±8000 V HBM ESD for shunt-based applications AEC-Q100 qualified EMI filters included High common-mode voltage range −2 V to +50 V operating −20 V to +70 V survival Buffered output voltage Gain = 14 V/V Low-pass filter (single-pole or two-pole) Wide operating temperature range: −40°C to +125°C Excellent ac and dc performance ±1 mV typical voltage offset −5 ppm/°C typical gain drift 80 dB CMRR minimum dc to 10 kHz Qualified for automotive applications VS A1 AD8209A EMI FILTER +IN EMI FILTER –IN EMI FILTER A2 + + G=2 – G=7 – GND OUT 14511-001 FEATURES Figure 1. APPLICATIONS High-side current sensing Motor controls Solenoid controls Power management Low-side current sensing Diagnostic protection GENERAL DESCRIPTION The AD8209A is a single-supply difference amplifier ideal for amplifying and low-pass filtering small differential voltages in the presence of a large common-mode voltage. The input commonmode voltage range extends from −2 V to +50 V at a single 5 V supply. The AD8209A is qualified per AEC-Q100 specifications. The amplifier offers enhanced input overvoltage and ESD protection, and includes electromagnetic interference (EMI) filtering. Rev. A Automotive applications demand robust, precision components for improved system control. The AD8209A provides excellent ac and dc performance, minimizing errors in the application. Typical offset and gain drift in the MSOP package are less than 5 µV/°C and −5 ppm/°C, respectively. The device also delivers a minimum common-mode rejection ratio (CMRR) of 80 dB from dc to 10 kHz. The AD8209A features an externally accessible 100 kΩ resistor at the output of the preamplifier (A1) that can be used for lowpass filtering and for establishing gains other than 14 V/V. Document Feedback 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 ©2016 Analog Devices, Inc. All rights reserved. Technical Support www.analog.com AD8209A Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 High-Side Current Sensing with a Low-Side Switch ............. 11 Applications ....................................................................................... 1 High Rail Current Sensing ........................................................ 11 Functional Block Diagram .............................................................. 1 Low-Side Current Sensing ........................................................ 11 General Description ......................................................................... 1 Gain Adjustment ........................................................................ 12 Revision History ............................................................................... 2 Gain Trim .................................................................................... 13 Specifications..................................................................................... 3 Low-Pass Filtering ...................................................................... 13 Absolute Maximum Ratings ............................................................ 4 ESD Caution .................................................................................. 4 High Line Current Sensing with Low-Pass Filtering and Gain Adjustment .................................................................................. 14 Pin Configuration and Function Descriptions ............................. 5 Outline Dimensions ....................................................................... 15 Typical Performance Characteristics ............................................. 6 Ordering Guide .......................................................................... 15 Theory of Operation ...................................................................... 10 Automotive Products ................................................................. 15 Applications Information .............................................................. 11 REVISION HISTORY 11/2016—Rev. 0 to Rev. A Change to Figure 27 ....................................................................... 11 7/2016—Revision 0: Initial Version Rev. A | Page 2 of 15 Data Sheet AD8209A SPECIFICATIONS Operating temperature (TOPR) = −40°C to +125°C, TA = 25°C, VS = 5 V, RL = 25 kΩ (RL is the output load resistor), unless otherwise noted. Table 1. Parameter SYSTEM GAIN Initial Error vs. Temperature Gain Drift VOLTAGE OFFSET Initial Input Offset (Referred to Input (RTI)) Input Offset (RTI) over Temperature Voltage Offset vs. Temperature INPUT Input Impedance Differential Common Mode VCM (Continuous) CMRR 1 PREAMPLIFIER (A1) Gain Gain Error Output Voltage Range Output Resistance OUTPUT BUFFER (A2) Gain Gain Error Output Voltage Range 3, 4 Output Voltage Range 5 Input Bias Current Output Resistance DYNAMIC RESPONSE System Bandwidth Slew Rate NOISE 0.1 Hz to 10 Hz Spectral Density, 1 kHz (RTI) POWER SUPPLY Operating Range Quiescent Current Quiescent Current vs. Temperature Power Supply Rejection Ratio (PSRR) TEMPERATURE RANGE Test Conditions/Comments Min Typ Max Unit V/V % ppm/°C 14 0.075 V ≤ VOUT ≤ (VS − 0.1 V), dc, TOPR TOPR −5 ±0.15 ±15 Input common-mode voltage (VCM) = 0.15 V, at TA ±1 ±2 mV ±4 mV +20 µV/°C 440 220 +50 kΩ kΩ V dB dB VCM = 0 V, TOPR VCM = 0 V, TOPR −20 VCM = −2 V to +50 V, dc f = dc to 10 kHz, 2 TOPR 360 180 −2 80 80 400 200 100 7 0.0375 V ≤ VOUT ≤ (VS − 0.1 V), dc, TOPR +0.3 VS − 0.1 103 V/V % V kΩ −0.3 0.05 +0.3 VS − 0.1 V/V % V 0.05 VS − 0.1 50 −0.3 0.025 97 100 2 0.075 V ≤ VOUT ≤ (VS − 0.1 V), dc, TOPR RL = 25 kΩ, differential input = 0 V, TOPR; Pin 3 (A1 output) driving Pin 4 (A2 input) Pin 4 (A2 input) driven with an external source TOPR RL = 1 kΩ, frequency = dc VIN = 0.01 V p-p, VOUT = 0.14 V p-p VIN = 0.28 V, VOUT = 4 V step 2 V nA Ω 100 1 kHz V/µs 20 500 µV p-p nV/√Hz 4.5 Typical at TA VOUT = 0.1 V dc, VS = 5 V, TOPR VS = 4.5 V to 5.5 V, TOPR 70 For specified performance at TOPR −40 5.5 1.6 2.7 80 +125 V mA mA dB °C Source imbalance < 2 Ω. The AD8209A preamplifier exceeds 80 dB CMRR at 10 kHz. However, because the output is available only via the 100 kΩ resistor, even a small amount of pin to pin capacitance between the ±IN pins and the A1 and A2 pins can couple an input common-mode signal larger than the greatly attenuated preamplifier output. The effect of pin to pin coupling can be neglected in all applications by using a filter capacitor from Pin 3 to GND. 3 The output voltage range of the AD8209A varies depending on the load resistance and temperature. For additional information on this specification, refer to Figure 12 and Figure 13. 4 The output voltage range of A2 assumes that Pin 3 (A1 output) and Pin 4 (A2 input) are shorted together. A 25 kΩ load resistor is used for testing. 5 The output voltage range of A2 assumes Pin 4 (A2 input) is driven with an external voltage source. A 25 kΩ load resistor is used for testing. 1 2 Rev. A | Page 3 of 15 AD8209A Data Sheet ABSOLUTE MAXIMUM RATINGS Table 2. Parameter Supply Voltage Continuous Input Voltage (Common Mode) Differential Input Voltage Reversed Supply Voltage Protection ESD Human Body Model for Shunt-Based Applications1 Operating Temperature Range Storage Temperature Range Output Short-Circuit Duration Lead Temperature Range (Soldering 10 sec) 1 Rating 9V −20 V to +70 V ±16 V 0.3 V ±8000 V −40°C to +125°C −65°C to +150°C Indefinite 300°C Stresses at or above those listed under Absolute Maximum Ratings may cause permanent damage to the product. This is a stress rating only; functional operation of the product at these or any other conditions above those indicated in the operational section of this specification is not implied. Operation beyond the maximum operating conditions for extended periods may affect product reliability. ESD CAUTION Shunt-based applications have a low impedance shunt resistor between +IN and −IN. See Figure 24 for an example of a shunt-based application. Rev. A | Page 4 of 15 Data Sheet AD8209A PIN CONFIGURATION AND FUNCTION DESCRIPTIONS –IN +IN VS GND GND A1 3 TOP VIEW (Not to Scale) A2 4 8 +IN 7 VS 6 DNC 5 OUT DNC = DO NOT CONNECT A1 A2 OUT 14511-003 AD8209A 14511-002 –IN 1 GND 2 Figure 2. Pin Configuration Figure 3. Metallization Photograph Table 3. Pin Function Descriptions1 Pin No. 1 N/A 2 2 3 4 5 N/A N/A 6 Mnemonic −IN OPEN GND GND A1 A2 OUT OPEN OPEN DNC Coordinates X Y −305 +375 −305 +282 −309 +149 −326 −7 −321 −185 −321 −375 +321 −345 +322 −162 +327 −54 Not applicable Not applicable Size (μm) 70 × 70 70 × 70 70 × 142 70 × 70 70 × 142 70 × 70 70 × 142 70 × 70 70 × 70 Not applicable 7 N/A 8 VS OPEN +IN +309 +305 +305 70 × 70 70 × 70 70 × 70 1 +185 +375 +282 N/A means not applicable. Rev. A | Page 5 of 15 Description Inverting Input. Bond pads are not connected to any external pins. Ground. Ground. Preamplifier (A1) Output. Buffer (A2) Input. Buffer (A2) Output. No Connect. Bond pads are not connected to any external pins. Do Not Connect. Do not connect to this pin; Pin 6 does not connect to any bond pads. Supply. Bond pads are not connected to any external pins. Noninverting Input. AD8209A Data Sheet TYPICAL PERFORMANCE CHARACTERISTICS TOPR = −40°C to +125°C, TA = 25°C, VS = 5 V, RL = 25 kΩ (RL is the output load resistor), unless otherwise noted. 1000 0.70 0.55 750 0.40 500 GAIN ERROR (ppm) VOSI (mV) 0.25 0.10 –0.05 –0.20 –0.35 250 0 –250 –500 –0.50 –20 0 20 40 60 80 100 120 140 TEMPERATURE (°C) –1000 –40 14511-004 –0.80 –40 0 –20 20 40 60 80 120 100 140 TEMPERATURE (°C) Figure 4. Offset (VOSI) vs. Temperature 14511-007 –750 –0.65 Figure 7. Gain Error vs. Temperature 30 1.0 TOTAL INPUT BIAS CURRENT (mA) 25 20 15 GAIN (dB) 10 5 0 –5 –10 0.8 0.6 0.4 0.2 0 –0.2 10000 100000 –0.4 –24 14511-005 –20 1000 1000000 FREQUENCY (Hz) 12 24 36 48 60 72 Figure 8. Total Input Bias Current vs. Input Common-Mode Voltage, +IN and −IN Pins Connected (Shorted) 140 –60 130 –55 A2 INPUT BIAS CURRENT (nA) 120 110 100 90 80 70 60 50 –40°C +25°C +125°C –50 –45 –40 –35 –30 –25 –20 100 1k 10k FREQUENCY (Hz) Figure 6. CMRR vs. Frequency 100k 1M –10 A2 INPUT VOLTAGE (V) 14511-009 –15 40 14511-006 CMRR (dB) 0 INPUT COMMON-MODE (V) Figure 5. Small Signal Bandwidth 30 10 –12 14511-008 –15 Figure 9. A2 Input Bias Current vs. A2 Input Voltage and Temperature Rev. A | Page 6 of 15 Data Sheet AD8209A 2.0 OUTPUT VOLTAGE RANGE (V) MAXIMUM OUTPUT SINK CURRENT (mA) 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 14511-010 0 TEMPERATURE (°C) 0 1 2 3 4 5 6 7 8 9 10 11 12 OUTPUT SINK CURRENT (mA) Figure 13. A2 Output Voltage Range from GND vs. Output Sink Current Figure 10. Maximum Output Sink Current vs. Temperature 8.0 INPUT 100mV/DIV 7.0 OUTPUT 6.0 500mV/DIV –20 0 20 40 60 80 100 120 140 TEMPERATURE (°C) 14511-014 5.0 TIME (2μs/DIV) 14511-011 MAXIMUM OUTPUT SOURCE CURRENT (mA) 9.0 4.0 –40 Figure 14. Rise Time Figure 11. Maximum Output Source Current vs. Temperature 5.0 100mV/DIV 4.0 INPUT 3.5 3.0 500mV/DIV 2.5 2.0 OUTPUT 0 1 2 3 4 5 6 7 8 OUTPUT SOURCE CURRENT (mA) TIME (2μs/DIV) Figure 15. Fall Time Figure 12. A2 Output Voltage Range vs. Output Source Current Rev. A | Page 7 of 15 14511-015 1.5 14511-012 OUTPUT VOLTAGE RANGE (V) 4.5 1.0 14511-013 0.2 AD8209A Data Sheet 200mV/DIV 2V/DIV INPUT 2V/DIV 0.01%/DIV TIME (2μs/DIV) 14511-018 14511-016 OUTPUT TIME (20μs/DIV) Figure 18. Settling Time, Rising Figure 16. Differential Overload Recovery, Rising 200mV/DIV 2V/DIV INPUT 2V/DIV 0.01%/DIV TIME (20μs/DIV) Figure 19. Settling Time, Falling Figure 17. Differential Overload Recovery, Falling Rev. A | Page 8 of 15 14511-019 TIME (2μs/DIV) 14511-017 OUTPUT Data Sheet AD8209A –3 –2 –1 0 1 2 3 4 VOS (mV) –20 –5 0 5 10 OFFSET DRIFT (µV/°C) 15 20 14511-021 –10 –5 0 5 10 Figure 22. Gain Drift Distribution COUNT –15 –10 GAIN DRIFT (ppm /°C) Figure 20. Offset Distribution –20 –15 Figure 21. Offset Drift Distribution Rev. A | Page 9 of 15 15 20 14511-022 –4 14511-020 COUNT COUNT +125°C +25°C –40°C AD8209A Data Sheet THEORY OF OPERATION The AD8209A is a single-supply difference amplifier typically used to amplify a small differential voltage in the presence of rapidly changing, high common-mode voltages. The AD8209A consists of two amplifiers (A1 and A2), a resistor network, a small voltage reference, and a bias circuit (not shown); see Figure 23. The set of input attenuators preceding A1 consist of RA, RB, and RC, which feature a combined series resistance of approximately 400 kΩ ± 20%. The purpose of these resistors is to attenuate the input voltage to match the input voltage range of A1. This balanced resistor network attenuates the common-mode signal by a ratio of 1/14. The A1 amplifier inputs are held within the power supply range, even as Pin 1 and Pin 8 exceed the supply or fall below the common (ground). A reference voltage of 350 mV biases the attenuator above ground, allowing Amplifier A1 to operate in the presence of negative common-mode voltages. The input resistor network also attenuates normal (differential) mode voltages. Therefore, A1 features a gain of 97 V/V to provide a total system gain, from ±IN to the output of A1, equal to 7 V/V, as shown in the following equation: A low-pass filter can be easily implemented by connecting A1 to A2 and placing a capacitor to ground (see Figure 32). The value of RF1 and RF2 is 10 kΩ, providing a gain of 2 V/V for Amplifier A2. When connecting Pin A1 and Pin A2 together, the AD8209A provides a total system gain equal to Total Gain of (A1 + A2) (V/V) = 7 (V/V) × 2 (V/V) = 14 V/V at the output of A2 (the OUT pin). The ratios of RA, RB, RC, and RF are trimmed to a high level of precision, allowing a typical CMRR value that exceeds 80 dB. This performance is accomplished by laser trimming the resistor ratio matching to better than 0.01%. –IN RA +IN VS RA – RF RB RG RC RC A2 RFILTER + + RB A1 A1 OUT A2 – RF1 RF RM RF2 A precision trimmed, 100 kΩ resistor is placed in series with the output of Amplifier A1. The user has access to this resistor via an external pin (A1). Rev. A | Page 10 of 15 14511-025 350mV Gain (A1) = 1/14 (V/V) × 97 (V/V) = 7 V/V GND Figure 23. Simplified Schematic Data Sheet AD8209A APPLICATIONS INFORMATION HIGH-SIDE CURRENT SENSING WITH A LOW-SIDE SWITCH HIGH RAIL CURRENT SENSING In load control configurations for high-side current sensing with a low-side switch, the pulse-width modulation (PWM) controlled switch is ground referenced. An inductive load (solenoid) connects to a power supply/battery. A resistive shunt is placed between the switch and the load (see Figure 24). An advantage of placing the shunt on the high side is that the entire current, including the recirculation current, is monitored because the shunt remains in the loop when the switch is off. In addition, shorts to ground can be detected with the shunt on the high side, enhancing the diagnostics of the control loop. 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. In the high rail current sensing configuration, the shunt resistor is referenced to the battery. High voltage is present at the inputs of the current sense amplifier. When the shunt is battery referenced, the AD8209A produces a linear ground-referenced analog output. Additionally, the AD8214 can be used to provide an overcurrent detection signal in as little as 100 ns (see Figure 26). This feature is useful in high current systems where fast shutdown in overcurrent conditions is essential. OVERCURRENT DETECTION (