Sample & Buy Product Folder Support & Community Tools & Software Technical Documents INA270A-Q1, INA271A-Q1 SBOS401C – JULY 2007 – REVISED APRIL 2016 INA27xA-Q1 Automotive Grade, –16V to +80V, Low- or High-side, High-Speed, Voltage Output Current Sense Amplifier With Simplified Filter Inputs 1 Features 2 Applications • • • • • • 1 • • • • • • • • Qualified for Automotive Applications AEC-Q100 Qualified With the Following Results: – Device Temperature Grade 1: –40°C to +125°C Ambient Operating Temperature Range – Device HBM ESD Classification Level 2 – Device CDM ESD Classification Level C6 Pinout Optimized for External Filtering Wide Common-Mode Range: –16 V to +80 V Accuracy: – CMRR: 120 dB – ±2.5-mV Offset (Maximum) – ±1% Gain Error (Maximum) – 20-μV/°C Offset Drift (Maximum) – 55-ppm/°C Gain Drift (Maximum) Bandwidth: Up to 130 kHz Two Gain Options Available: – 14 V/V (INA270A-Q1) – 20 V/V (INA271A-Q1) Quiescent Current: 900 μA (Maximum) Power Supply: 2.7 V to 18 V Packages: SOIC-8 Electric Power Steering (EPS) Systems Body Control Modules Brake Systems Electronic Stability Control (ESC) Systems 3 Description The INA270A-Q1 and INA271A-Q1 (INA27xA-Q1) family of current-shunt monitors with voltage output can sense voltage drops across current shunts at common-mode voltages from –16 V to +80 V, independent of the supply voltage. The INA27xA-Q1 pinouts readily enable filtering. The INA27xA-Q1 devices are available with two output voltage scales: 14 V/V and 20 V/V. The 130kHz bandwidth simplifies use in current-control loops. The INA27xA-Q1 operates from a single 2.7-V to 18V supply, drawing a maximum of 900 μA of supply current. They are specified over the extended operating temperature range of –40°C to +125°C and are offered in an SOIC-8 package. Device Information(1) PART NUMBER INA270A-Q1 PACKAGE SOIC (8) INA271A-Q1 BODY SIZE (NOM) 4.90 mm × 3.91 mm (1) For all available packages, see the orderable addendum at the end of the data sheet. Simplified Schematic RS −16 V to +80 V Supply Load Single-Pole Filter Capacitor +2.7 V to +18 V IN+ IN– 5 kW PRE OUT BUF IN 0.01 µF VS 0.1 µF 5 kW OUT A1 96 kW A2 RL GND Copyright © 2016, Texas Instruments Incorporated 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. INA270A-Q1, INA271A-Q1 SBOS401C – JULY 2007 – REVISED APRIL 2016 www.ti.com Table of Contents 1 2 3 4 5 6 7 8 Features .................................................................. Applications ........................................................... Description ............................................................. Revision History..................................................... Device Comparison Table..................................... Pin Configuration and Functions ......................... Specifications......................................................... 1 1 1 2 3 3 3 7.1 7.2 7.3 7.4 7.5 7.6 3 4 4 4 4 6 Absolute Maximum Ratings ...................................... ESD Ratings.............................................................. Recommended Operating Conditions....................... Thermal Information .................................................. Electrical Characteristics........................................... Typical Characteristics .............................................. Detailed Description .............................................. 9 8.1 Overview ................................................................... 9 8.2 Functional Block Diagram ......................................... 9 8.3 Feature Description................................................... 9 8.4 Device Functional Modes.......................................... 9 9 Application and Implementation ........................ 11 9.1 Application Information............................................ 11 9.2 Typical Application .................................................. 14 10 Power Supply Recommendations ..................... 16 10.1 Shutdown .............................................................. 16 11 Layout................................................................... 17 11.1 Layout Guidelines ................................................. 17 11.2 Layout Example .................................................... 17 12 Device and Documentation Support ................. 18 12.1 12.2 12.3 12.4 12.5 Related Links ........................................................ Community Resources.......................................... Trademarks ........................................................... Electrostatic Discharge Caution ............................ Glossary ................................................................ 18 18 18 18 18 13 Mechanical, Packaging, and Orderable Information ........................................................... 18 4 Revision History NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Revision B (February 2010) to Revision C Page • Updated data sheet title, Features, and Applications............................................................................................................. 1 • Updated device name from INA270-Q1 and INA271-Q1 to INA270A-Q1 and INA271A-Q1 ................................................. 1 • Added A-Q1 to INA270 and INA271 throughout document ................................................................................................... 1 • Added Device Information table, ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, First- or Second-Order Filtering section Layout section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information section. ................................................................................................................................................................ 1 • Changed V+ to VS throughout ................................................................................................................................................ 3 • Added equation (VIN+ + VIN–)/2 to common-mode in Absolute Maximum Ratings table......................................................... 3 • Updated VSENSE equation........................................................................................................................................................ 4 • Changed Input offset voltage temperature coefficient symbol ............................................................................................... 4 2 Submit Documentation Feedback Copyright © 2007–2016, Texas Instruments Incorporated Product Folder Links: INA270A-Q1 INA271A-Q1 INA270A-Q1, INA271A-Q1 www.ti.com SBOS401C – JULY 2007 – REVISED APRIL 2016 5 Device Comparison Table DEVICE GAIN INA270A-Q1 14 V/V INA271A-Q1 20 V/V 6 Pin Configuration and Functions D Package 8-Pin SOIC Top View (1) IN± 1 8 IN+ GND 2 7 NC PRE OUT 3 6 VS BUF IN 4 5 OUT (1) NC – No internal connection Pin Functions PIN TYPE (1) DESCRIPTION NAME NO. BUF IN 4 AI Buffer Input. Connect to output of filter from PRE OUT GND 2 A Ground IN– 1 AI Negative input. Connect to load side of shunt resistor. IN+ 8 AI Positive input. Connect to supply side of shunt resistor. NC 7 — Not internally connected. Connect to ground. PRE OUT 3 AO Pre Amplifier Output. Connect to input of filter to BUF IN. OUT 5 AO Output VS 6 AI Power supply, 2.7 V to 18 V (1) A = Analog, AI = Analog input, AO = Analog output 7 Specifications 7.1 Absolute Maximum Ratings over operating free-air temperature range (unless otherwise noted) (1) MIN MAX UNIT VS Supply voltage 18 V VSENSE Differential analog input voltage range (VIN+ – VIN–) –18 18 V VCM Common-mode analog input voltage range (VIN+ + VIN–)/2 –16 80 V VO Analog output voltage range (OUT and PRE OUT) (GND – 0.3) (VS) + 0.3 V II Input current (any pin) 5 mA TJ Maximum junction temperature 150 °C TA Operating free-air temperature –40 125 °C Tstg Storage temperature –65 150 °C (1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. Copyright © 2007–2016, Texas Instruments Incorporated Product Folder Links: INA270A-Q1 INA271A-Q1 Submit Documentation Feedback 3 INA270A-Q1, INA271A-Q1 SBOS401C – JULY 2007 – REVISED APRIL 2016 www.ti.com 7.2 ESD Ratings VALUE Human-body model (HBM), per AEC Q100-002 (1) V(ESD) (1) Electrostatic discharge UNIT 2000 Machine Model (MM) 100 Charged-device model (CDM), per AEC Q100-011 1000 V AEC Q100-002 indicates that HBM stressing shall be in accordance with the ANSI/ESDA/JEDEC JS-001 specification. 7.3 Recommended Operating Conditions MIN NOM MAX VS Supply voltage 2.7 5 18 UNIT V VCM Common mode input –16 12 80 V TA Operating free-air temperature –40 25 125 °C 7.4 Thermal Information INA27xA-Q1 THERMAL METRIC (1) D (SOIC) UNIT 8 PINS RθJA Junction-to-ambient thermal resistance 78.8 °C/W RθJC(top) Junction-to-case (top) thermal resistance 71.6 °C/W RθJB Junction-to-board thermal resistance 68.2 °C/W ψJT Junction-to-top characterization parameter 22 °C/W ψJB Junction-to-board characterization parameter 67.6 °C/W RθJC(bot) Junction-to-case (bottom) thermal resistance n/a °C/W (1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report, SPRA953. 7.5 Electrical Characteristics TA = 25°C, VS = 5 V, VCM = 12 V, VSENSE = 100 mV, PRE OUT connected to BUF IN (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT 0.15 (VS – 0.2)/ Gain V 80 V Input VSENSE Full-scale input voltage VSENSE = VIN+ - VIN– VCM Common-mode input voltage TA = –40°C to +125°C –16 VIN+ = –16 V to +80 V 80 120 VIN+ = 12 V to 80 V, TA = –40°C to +125°C 100 120 CMRR Common-mode rejection VOS Offset voltage, RTI (1) dVOS/dT Input offset voltage temperature coefficient TA = –40°C to +125°C PSR Offset voltage power-supply rejection VS = 2.7 V to 18 V, VCM = 18 V, TA = –40°C to +125°C IIB Input bias current ZO Output impedance (2) (1) (2) 4 ±0.5 TA = –40°C to +125°C dB 2.5 ±3 mV 2.5 20 μV/°C 5 100 μV/V IN– pin, TA = –40°C to +125°C full range ±8 ±16 PRE OUT pin 96 kΩ Buffer input bias current –50 nA Buffer input bias current temperature coefficient ±0.3 nA/°C μA RTI = referred to input Initial resistor variation is ±30% with an additional –2200-ppm/°C temperature coefficient. Submit Documentation Feedback Copyright © 2007–2016, Texas Instruments Incorporated Product Folder Links: INA270A-Q1 INA271A-Q1 INA270A-Q1, INA271A-Q1 www.ti.com SBOS401C – JULY 2007 – REVISED APRIL 2016 Electrical Characteristics (continued) TA = 25°C, VS = 5 V, VCM = 12 V, VSENSE = 100 mV, PRE OUT connected to BUF IN (unless otherwise noted) PARAMETER Output (VSENSE ≥ 20 mV) TEST CONDITIONS MIN TYP G Gain GBUF Output buffer gain INA270A-Q1 14 INA271A-Q1 20 UNIT Total gain error VSENSE = 20 mV to 100 mV Total gain error temperature coefficient TA = –40°C to +125°C Total output error (4) V/V 2 ±0.2% ZO MAX (3) TA = –40°C to +125°C TA = –40°C to +125°C V/V ±1% ±2% 50 ±0.75% ±2.2% ±1% ±3% ppm/°C Nonlinearity error VSENSE = 20 mV to 100 mV ±0.002% Output impedance OUT pin 1.5 Ω Maximum capacitive load No sustained oscillation 10 nF Voltage Output (5) Swing to VS power-supply rail Swing to GND RL = 10 kΩ to GND, TA = –40°C to +125°C RL = 10 kΩ to GND, TA = –40°C to +125°C VS – 0.05 VS – 0.2 V VGND + V + 0.05 0.003 GND V Frequency Response BW Bandwidth CL = 5 pF 130 kHz φm Phase margin CL < 10 nF 40 degrees SR Slew rate 1 V/μs ts Settling time (1%) 2 μs 40 nV/√Hz VSENSE = 10 mV to 100 mV, CL = 5 pF Noise, RTI (1) Vn Voltage noise density Power Supply IQ (3) (4) (5) Quiescent current VOUT = 2 V 700 900 VSENSE = 0 V, TA = –40°C to +125°C 350 950 μA For output behavior when VSENSE < 20 mV, see Application Information Total output error includes effects of gain error and VOS. See Typical Characteristics curve Output Swing vs Output Current and Accuracy Variations as a Result of VSENSE and Common-Mode Voltage in the Application Information section. Copyright © 2007–2016, Texas Instruments Incorporated Product Folder Links: INA270A-Q1 INA271A-Q1 Submit Documentation Feedback 5 INA270A-Q1, INA271A-Q1 SBOS401C – JULY 2007 – REVISED APRIL 2016 www.ti.com 7.6 Typical Characteristics 45 45 40 40 35 35 30 Gain (dB) Gain (dB) TA = 25°C, VS = 12 V, VCM = 12 V, VSENSE = 100 mV (unless otherwise noted) G = 20 25 G = 14 20 30 G = 20 25 G = 14 20 15 15 10 10 5 5 10k 100k 10k 1M 100k CLOAD = 1000 pF CLOAD = 0 pF Figure 1. Gain vs Frequency Figure 2. Gain vs Frequency 140 18 130 Common−Mode and Power−Supply Rejection (dB) 20 16 14 VOut (V) 20V/V 12 10 8 14V/V 6 4 2 1200 120 CMRR 110 100 90 PSR 80 70 60 50 40 1300 1100 900 1000 800 700 500 600 400 200 300 0 0 100 1M Frequency (Hz) Frequency (Hz) 10 100 1k VDifferential (mV) 100k 10k Frequency (Hz) VS = 18 V Figure 4. Common-Mode and Power-Supply Rejection vs Frequency 4.0 0.1 3.5 0.09 0.08 3.0 Output Error (%) Total Output Error (% error of the ideal output value) Figure 3. Gain Plot 2.5 2.0 1.5 1.0 0.07 0.06 0.05 0.04 0.03 0.02 0.5 0.01 0 0 50 100 150 200 250 300 350 400 450 500 0 –16 –12 –8 –4 VSENSE(mV) Figure 5. Total Output Error vs VSENSE 6 Submit Documentation Feedback 0 4 8 12 16 20 ... 76 80 Common-Mode Voltage (V) Figure 6. Output Error vs Common-Mode Voltage Copyright © 2007–2016, Texas Instruments Incorporated Product Folder Links: INA270A-Q1 INA271A-Q1 INA270A-Q1, INA271A-Q1 www.ti.com SBOS401C – JULY 2007 – REVISED APRIL 2016 Typical Characteristics (continued) TA = 25°C, VS = 12 V, VCM = 12 V, VSENSE = 100 mV (unless otherwise noted) 12 1000 11 10 9 800 25°C 8 700 –40°C 125°C 7 6 VS = 3V Sourcing Current 25°C 5 4 600 IQ (µA) Output Voltage (V) 900 VS = 12V Sourcing Current 500 400 –40°C 300 3 200 2 100 1 125°C 0 0 0 5 10 20 15 25 30 0 1 2 Output Current (mA) 3 4 5 7 6 8 9 10 Output Voltage (V) Output stage is designed to source current. Current sinking capability is approximately 400 μA. Figure 7. Positive Output Voltage Swing vs Output Current Figure 8. Quiescent Current vs Output Voltage 34 VS= 12 V VS= 2.7 V 775 IQ (µA) 675 575 475 VS= 12 V 375 VS = 2.7 V 275 175 −16 −12 −8 −4 Output Short-Circuit Current (mA) 875 –40°C 30 25°C 26 125°C 22 18 14 10 6 0 4 8 12 16 20 ... 2.5 3.5 76 80 4.5 5.5 6.5 7.5 8.5 9.5 10.5 11.5 17 18 Supply Voltage (V) VCM(V) Figure 10. Output Short-Circuit Current vs Supply Voltage Figure 9. Quiescent Current vs Common-Mode Voltage 200 150 Gain (dB) Population Phase 100 50 Gain 80 82 84 86 88 90 92 94 96 98 100 102 104 106 108 110 112 114 116 118 120 0 −50 10 100 RPREOUT (kΩ) 1k 10k 100k 1M 10M Frequency(Hz) Figure 11. Preout Output Resistance Production Distribution Figure 12. Buffer Gain vs Frequency Copyright © 2007–2016, Texas Instruments Incorporated Product Folder Links: INA270A-Q1 INA271A-Q1 Submit Documentation Feedback 7 INA270A-Q1, INA271A-Q1 SBOS401C – JULY 2007 – REVISED APRIL 2016 www.ti.com Typical Characteristics (continued) 50 mV/div 500 mV/div TA = 25°C, VS = 12 V, VCM = 12 V, VSENSE = 100 mV (unless otherwise noted) 10 µs/div 10 µs/div Figure 13. Small-Signal Step Response 10-mV to 20-mV Input 8 Submit Documentation Feedback Figure 14. Large-Signal Step Response 10-mV to 100-mV Input Copyright © 2007–2016, Texas Instruments Incorporated Product Folder Links: INA270A-Q1 INA271A-Q1 INA270A-Q1, INA271A-Q1 www.ti.com SBOS401C – JULY 2007 – REVISED APRIL 2016 8 Detailed Description 8.1 Overview The INA27xA-Q1 is a family of voltage output current-sense amplifiers. INA27xA-Q1 operates over a wide common-mode voltage range (–16 V to +80 V). The package brings out the output of the pre amplifier stage (PRE OUT) and the input to the output buffer stage (BUF IN). This pinout readily enables filtering, see First- or Second-Order Filtering. 8.2 Functional Block Diagram IN+ IN- PRE OUT BUF IN VS A1 OUT A2 GND Copyright © 2016, Texas Instruments Incorporated 8.3 Feature Description 8.3.1 Output Voltage Range The output of the INA27xA-Q1 is accurate within the output voltage swing range set by the power-supply pin, VS. 8.4 Device Functional Modes 8.4.1 First- or Second-Order Filtering The INA27xA-Q1 devices readily enable the inclusion of filtering between the preamp output and buffer input. Single-pole filtering can be accomplished with a single capacitor because of the 96-kΩ output impedance at PRE OUT on pin 3 (see Figure 15a). The INA27xA-Q1 devices readily lend themselves to second-order Sallen-Key configurations (see Figure 15b). When designing these configurations consider that the PRE OUT 96-kΩ output impedance exhibits an initial variation of ±30% with the addition of a –2200-ppm/°C temperature coefficient. Copyright © 2007–2016, Texas Instruments Incorporated Product Folder Links: INA270A-Q1 INA271A-Q1 Submit Documentation Feedback 9 INA270A-Q1, INA271A-Q1 SBOS401C – JULY 2007 – REVISED APRIL 2016 www.ti.com Device Functional Modes (continued) RS Supply Load RS Supply Load Second-Order, Sallen-Key Filter Connection CFILT Single-Pole Filter Capacitor RS CFILT +2.7 V to +18 V IN+ PRE OUT IN– 5 kW BUF IN +2.7 V to +18 V VS IN+ 5 kW 5 kW Output A1 96 kW A2 PRE OUT IN– BUF IN VS 5 kW A1 Output 96 kW A2 RL RL GND GND a ) Single-Pole Filter b ) Second−Order, Sallen−Key Filter Copyright © 2016, Texas Instruments Incorporated A. The INA27xA-Q1 can be easily connected for first-order or second-order filtering. Remember to use the appropriate buffer gain (INA270A-Q1 = 1.4, INA271A-Q1 = 2) when designing Sallen-Key configurations. Figure 15. First-Order or Second-Order Filtering 10 Submit Documentation Feedback Copyright © 2007–2016, Texas Instruments Incorporated Product Folder Links: INA270A-Q1 INA271A-Q1 INA270A-Q1, INA271A-Q1 www.ti.com SBOS401C – JULY 2007 – REVISED APRIL 2016 9 Application and Implementation NOTE Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality. 9.1 Application Information The INA27xA-Q1 measures the voltage developed across a current-sensing resistor when current passes through it. There is also a filtering feature to remove unwanted transients and smooth the output voltage. 9.1.1 Basic Connection Figure 16 illustrates the basic connection of the INA27xA-Q1. The input pins, IN+ and IN–, should be connected as closely as possible to the shunt resistor to minimize any resistance in series with the shunt resistance. Powersupply bypass capacitors are required for stability. Applications with noisy or high-impedance power supplies may require additional decoupling capacitors to reject power-supply noise. Minimum bypass capacitors of 0.01 μF and 0.1 μF in value should be placed close to the supply pins. Although not mandatory, an additional 10µF electrolytic capacitor placed in parallel with the other bypass capacitors may be useful in applications with particularly noisy supplies. RS −16 V to +80 V Supply Load Single-Pole Filter Capacitor +2.7 V to +18 V IN+ IN– 5 kW PRE OUT BUF IN 0.01 µF VS 0.1 µF 5 kW OUT A1 96 kW A2 RL GND Copyright © 2016, Texas Instruments Incorporated Figure 16. INA270A-Q1 Basic Connection 9.1.2 Selecting RS The value chosen for the shunt resistor, RS, depends on the application and is a compromise between smallsignal accuracy and maximum permissible voltage loss in the measurement line. High values of RS provide better accuracy at lower currents by minimizing the effects of offset, while low values of RS minimize voltage loss in the supply line. For most applications, best performance is attained with an RS value that provides a full-scale shunt voltage range of 50 mV to 100 mV. Maximum input voltage for accurate measurements is (VS – 0.2)/Gain. Copyright © 2007–2016, Texas Instruments Incorporated Product Folder Links: INA270A-Q1 INA271A-Q1 Submit Documentation Feedback 11 INA270A-Q1, INA271A-Q1 SBOS401C – JULY 2007 – REVISED APRIL 2016 www.ti.com Application Information (continued) 9.1.3 Accuracy Variations as a Result of VSENSE and Common-Mode Voltage The accuracy of the INA27xA-Q1 current-shunt monitors is a function of two main variables: VSENSE (VIN+ – VIN–) and common-mode voltage, VCM, relative to the supply voltage, VS. VCM is expressed as (VIN+ + VIN–)/2; however, in practice, VCM is seen as the voltage at VIN+ because the voltage drop across VSENSE is usually small. This section addresses the accuracy of these specific operating regions: Normal Case 1: VSENSE ≥ 20 mV, VCM ≥ VS Normal Case 2: VSENSE ≥ 20 mV, VCM < VS Low VSENSE Case 1: VSENSE < 20 mV, –16 V ≤ VCM < 0 Low VSENSE Case 2: VSENSE < 20 mV, 0 V ≤ VCM ≤ VS Low VSENSE Case 3: VSENSE < 20 mV, VS < VCM ≤ 80 V 9.1.3.1 Normal Case 1: VSENSE ≥ 20 mV, VCM ≥ VS This region of operation provides the highest accuracy. Here, the input offset voltage is characterized and measured using a two-step method. First, the gain is determined by Equation 1. VOUT1 – VOUT2 G= 100 mV – 20 mV where • • VOUT1 = Output voltage with VSENSE = 100 mV VOUT2 = Output voltage with VSENSE = 20 mV (1) Then the offset voltage is measured at VSENSE = 100 mV and referred to the input (RTI) of the current-shunt monitor, as shown in Equation 2. VOUT1 – 100 mV VOSRTI (referred to input) = G (2) ( ( In Typical Characteristics, the Output Error vs Common-Mode Voltage curve shows the highest accuracy for the this region of operation. In this plot, VS = 12 V; for VCM ≥ 12 V, the output error is at its minimum. This case is also used to create the VSENSE ≥ 20 mV output specifications in Electrical Characteristics. 9.1.3.2 Low VSENSE Case 1: VSENSE < 20 mV, –16 V ≤ VCM < 0; and Low VSENSE Case 3: VSENSE < 20 mV, VS < VCM ≤ 80 V Although the INA270A-Q1 family of devices are not designed for accurate operation in either of these regions, some applications are exposed to these conditions. For example, when monitoring power supplies that are switched on and off while VS is still applied to the INA27xA-Q1 devices, it is important to know what the behavior of the devices is in these regions. As VSENSE approaches 0 mV, in these VCM regions, the device output accuracy degrades. A larger-than-normal offset can appear at the current-shunt monitor output with a typical maximum value of VOUT = 60 mV for VSENSE = 0 mV. As VSENSE approaches 20 mV, VOUT returns to the expected output value with accuracy as specified in Electrical Characteristics. Figure 17 illustrates this effect using the INA271A-Q1 (Gain = 20). 12 Submit Documentation Feedback Copyright © 2007–2016, Texas Instruments Incorporated Product Folder Links: INA270A-Q1 INA271A-Q1 INA270A-Q1, INA271A-Q1 www.ti.com SBOS401C – JULY 2007 – REVISED APRIL 2016 Application Information (continued) 0.40 0.36 0.32 VOUT (V) 0.28 0.24 Actual 0.20 0.16 Ideal 0.12 0.08 0.04 0 0 2 4 6 8 10 12 14 16 18 20 VSENSE (mV) Figure 17. Example for Low VSENSE Cases 1 and 3 (INA271A-Q1, Gain = 20) 9.1.3.3 Low VSENSE Case 2: VSENSE < 20 mV, 0 V ≤ VCM ≤ VS This region of operation is the least accurate for the INA27xA-Q1 family. To achieve the wide input commonmode voltage range, these devices use two operational amplifier (op amp) front ends in parallel. One op amp front end operates in the positive input common-mode voltage range, and the other in the negative input region. For this case, neither of these two internal amplifiers dominates and overall loop gain is very low. Within this region, VOUT approaches voltages close to linear operation levels for Normal Case 2. This deviation from linear operation becomes greatest the closer VSENSE approaches 0 V. Within this region, as VSENSE approaches 20 mV, device operation is closer to that described by Normal Case 2. Figure 18 illustrates this behavior for the INA271A-Q1. The VOUT maximum peak for this case is determined by maintaining a constant VS, setting VSENSE = 0 mV and sweeping VCM from 0 V to VS. The exact VCM at which VOUT peaks during this case varies from part to part. The maximum peak voltage for the INA270A-Q1 is 0.28 V; for the INA271A-Q1, the maximum peak voltage is 0.4 V. 0.48 INA271 VOUT Limit(1) 0.48 VCM1 0.40 Ideal VOUT (V) 0.36 0.32 VCM2 0.28 VCM3 0.24 0.20 0.16 VOUT limit at VSENSE = 0mV, 0 ≤ VCM1 ≤ VS VCM4 0.12 VCM2, VCM3, and VCM4 illustrate the variance from part to part of the VCM that can cause maximum VOUT with VSENSE < 20mV. 0.08 0.04 0 0 2 4 6 8 10 12 14 16 18 20 22 24 VSENSE (mV) Figure 18. Example for Low VSENSE Case 2 (INA271A-Q1, Gain = 20) 9.1.4 Transient Protection The –16-V to 80-V common-mode range of the INA27xA-Q1 is ideal for withstanding automotive fault conditions ranging from 12-V battery reversal up to 80-V transients, since no additional protective components are needed up to those levels. In the event that the INA27xA-Q1 devices are exposed to transients on the inputs in excess of their ratings, external transient absorption with semiconductor transient absorbers (zeners or Transzorbs) are necessary. Copyright © 2007–2016, Texas Instruments Incorporated Product Folder Links: INA270A-Q1 INA271A-Q1 Submit Documentation Feedback 13 INA270A-Q1, INA271A-Q1 SBOS401C – JULY 2007 – REVISED APRIL 2016 www.ti.com Application Information (continued) Use of MOVs or VDRs is not recommended except when they are used in addition to a semiconductor transient absorber. Select the transient absorber such that it never allows the INA27xA-Q1 to be exposed to transients greater than 80 V (that is, allow for transient absorber tolerance, as well as additional voltage because of transient absorber dynamic impedance). Despite the use of internal zener-type ESD protection, the INA27xA-Q1 devices are not suited to using external resistors in series with the inputs, since the internal gain resistors can vary up to ±30%, but the internal resistors are tightly matched. If gain accuracy is not important, then resistors can be added in series with the INA27xA-Q1 inputs, with two equal resistors on each input. 9.2 Typical Application RS −16 V to +80 V Supply Load Single-Pole Filter Capacitor +2.7 V to +18 V IN+ IN– 5 kW PRE OUT BUF IN 0.01 µF VS 0.1 µF 5 kW OUT A1 96 kW A2 RL GND Copyright © 2016, Texas Instruments Incorporated Figure 19. Filtering Configuration 9.2.1 Design Requirements In this application, the device is configured to measure a triangular periodic current at 10 kHz with filtering. The average current through the shunt is the information that is desired. This current can be either solenoid current or inductor current where current is being pulsed through. Selecting the capacitor size is based on the lowest frequency component to be filtered out. The amount of signal that is filtered out is dependant on this cutoff frequency. From the cutoff frequency, the attention is 20 dB per decade. 9.2.2 Detailed Design Procedure Without this filtering capability, an input filter must be used. When series resistance is added to the input, large errors also come into play because the resistance must be large to create a low cutoff frequency. By using a 10-nF capacitor for the single-pole filter capacitor, the 10-kHz signal is averaged. The cutoff frequency made by the capacitor is set at 166 Hz frequency. This frequency is well below the periodic frequency and reduces the ripple on the output and the average current can easily be measured. 14 Submit Documentation Feedback Copyright © 2007–2016, Texas Instruments Incorporated Product Folder Links: INA270A-Q1 INA271A-Q1 INA270A-Q1, INA271A-Q1 www.ti.com SBOS401C – JULY 2007 – REVISED APRIL 2016 Typical Application (continued) 9.2.3 Application Curves Figure 20 shows the output waveform without filtering. The output signal tracks the input signal with a large ripple. If this current is sampled by an ADC, many samples must be taken to average the current digitally. This process takes additional time to sample and average and is very time consuming, thus is unwanted for this application. 5 4.5 4.5 4 4 3.5 Output Voltage Shunt and Output (V) Shunt and Output (V) Figure 21 shows the output waveform with filtering. The output signal is filtered and the average can easily be measured with a small ripple. If this current is sampled by an ADC, only a few samples must be taken to average. Digital averaging is now not required and the time required is significantly reduced. 3.5 Output Voltage 3 2.5 2 1.5 3 2.5 2 1.5 1 1 Shunt Voltage Shunt Voltage 0.5 0.5 0 0 0 0.0002 0.0004 0.0006 100Ps/div 0.0008 0.001 0 0.0002 D001 Figure 20. Without Filtering Copyright © 2007–2016, Texas Instruments Incorporated Product Folder Links: INA270A-Q1 INA271A-Q1 0.0004 0.0006 100Ps/div 0.0008 0.001 D002 Figure 21. With Filtering Submit Documentation Feedback 15 INA270A-Q1, INA271A-Q1 SBOS401C – JULY 2007 – REVISED APRIL 2016 www.ti.com 10 Power Supply Recommendations The input circuitry of the INA27xA-Q1 can accurately measure beyond its power-supply voltage, VS. For example, the VS power supply can be 5 V, whereas the load power-supply voltage is up to 80 V. The output voltage range of the OUT terminal, however, is limited by the voltages on the power-supply pin. 10.1 Shutdown The INA27xA-Q1 devices do not provide a shutdown pin; however, because they consume a quiescent current less than 1 mA, they can be powered by either the output of logic gates or by transistor switches to supply power. Driving the gate low shuts down the INA27xA-Q1. Use a totem-pole output buffer or gate that can provide sufficient drive along with 0.1-μF bypass capacitor, preferably ceramic with good high-frequency characteristics. This gate should have a supply voltage of 3 V or greater, because the INA27xA-Q1 requires a minimum supply greater than 2.7 V. In addition to eliminating quiescent current, this gate also turns off the 10-μA bias current present at each of the inputs. NOTE The IN+ and IN– inputs are able to withstand full common-mode voltage under all powered and under-powered conditions. Figure 22 shows an example of the shutdown circuit. IL RS −16 V to +80 V Supply Single-Pole Filter Capacitor IN+ Negative and Positive Common-Mode Voltage IN– 5 kW PRE OUT Load BUF IN VS 5 kW VS > 3 V OUT A1 74HC04 0.01 µF 96 kW A2 RL GND Copyright © 2016, Texas Instruments Incorporated Figure 22. INA27xA-Q1 Example Shutdown Circuit Schematic 16 Submit Documentation Feedback Copyright © 2007–2016, Texas Instruments Incorporated Product Folder Links: INA270A-Q1 INA271A-Q1 INA270A-Q1, INA271A-Q1 www.ti.com SBOS401C – JULY 2007 – REVISED APRIL 2016 11 Layout 11.1 Layout Guidelines • • Connect the input pins to the sensing resistor using a Kelvin or 4-wire connection. This connection technique ensures that only the current-sensing resistor impedance is detected between the input pins. Poor routing of the current-sensing resistor commonly results in additional resistance present between the input pins. Given the very low ohmic value of the current resistor, any additional high-current carrying impedance can cause significant measurement errors. Place the power-supply bypass capacitor as closely as possible to the supply and ground pins. The recommended value of this bypass capacitor is 0.1 μF. Additional decoupling capacitance can be added to compensate for noisy or high-impedance power supplies. 11.1.1 RFI and EMI Attention to good layout practices is always recommended. Keep traces short and, when possible, use a printed circuit board (PCB) ground plane with surface-mount components placed as close to the device pins as possible. Small ceramic capacitors placed directly across amplifier inputs can reduce RFI and EMI sensitivity. PCB layout should locate the amplifier as far away as possible from RFI sources. Sources can include other components in the same system as the amplifier itself, such as inductors (particularly switched inductors handling a lot of current and at high frequencies). RFI can generally be identified as a variation in offset voltage or dc signal levels with changes in the interfering RF signal. If the amplifier cannot be located away from sources of radiation, shielding may be needed. Twisting wire input leads makes them more resistant to RF fields. The difference in input pin location of the INA27xA-Q1 versus the INA193 through INA198 may provide different EMI performance. 11.2 Layout Example Shunt Resistor IN- Single-Pole Filter Capacitor IN+ GND NC PRE OUT VS BUF IN Supply Bypass Capacitor Supply Voltage OUT Analog Output Via to Power or Ground Plane Via to Internal Layer Figure 23. INA27xA-Q1 Example Layout Copyright © 2007–2016, Texas Instruments Incorporated Product Folder Links: INA270A-Q1 INA271A-Q1 Submit Documentation Feedback 17 INA270A-Q1, INA271A-Q1 SBOS401C – JULY 2007 – REVISED APRIL 2016 www.ti.com 12 Device and Documentation Support 12.1 Related Links The table below lists quick access links. Categories include technical documents, support and community resources, tools and software, and quick access to sample or buy. Table 1. Related Links PARTS PRODUCT FOLDER SAMPLE & BUY TECHNICAL DOCUMENTS TOOLS & SOFTWARE SUPPORT & COMMUNITY INA270A-Q1 Click here Click here Click here Click here Click here INA271A-Q1 Click here Click here Click here Click here Click here 12.2 Community Resources The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of Use. TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help solve problems with fellow engineers. Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and contact information for technical support. 12.3 Trademarks E2E is a trademark of Texas Instruments. All other trademarks are the property of their respective owners. 12.4 Electrostatic Discharge Caution These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. 12.5 Glossary SLYZ022 — TI Glossary. This glossary lists and explains terms, acronyms, and definitions. 13 Mechanical, Packaging, and Orderable Information The following pages include mechanical, packaging, and orderable information. This information is the most current data available for the designated devices. This data is subject to change without notice and revision of this document. For browser-based versions of this data sheet, refer to the left-hand navigation. 18 Submit Documentation Feedback Copyright © 2007–2016, Texas Instruments Incorporated Product Folder Links: INA270A-Q1 INA271A-Q1 PACKAGE OPTION ADDENDUM www.ti.com 16-Feb-2016 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish MSL Peak Temp (2) (6) (3) Op Temp (°C) Device Marking (4/5) INA270AQDRQ1 ACTIVE SOIC D 8 2500 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 125 INA270 INA271AQDRQ1 ACTIVE SOIC D 8 2500 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 125 INA271 (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. (5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Device Marking for that device. (6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish value exceeds the maximum column width. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. 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