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INA301A1IDGKT

INA301A1IDGKT

  • 厂商:

    BURR-BROWN(德州仪器)

  • 封装:

    VSSOP8

  • 描述:

    IC COMPARATOR SENSING AMP 8VSSOP

  • 数据手册
  • 价格&库存
INA301A1IDGKT 数据手册
Sample & Buy Product Folder Support & Community Tools & Software Technical Documents INA301 SBOS713A – SEPTEMBER 2015 – REVISED FEBRUARY 2016 INA301 36-V, High-Speed, Zero-Drift, Voltage-Output, Current-Shunt Monitor with High-Speed, Overcurrent Comparator 1 Features 3 Description • • • The INA301 includes both a high common-mode, current-sensing amplifier and a high-speed comparator configured to detect overcurrent conditions through measuring the voltage developed across a current-sensing or current-shunt resistor and comparing that voltage to a defined threshold limit. The device features an adjustable limit threshold range that is set using a single external limit-setting resistor. This current-shunt monitor can measure differential voltage signals on common-mode voltages that can vary from 0 V up to 36 V, independent of the supply voltage. 1 • • • • • Wide Common-Mode Input Range: 0 V to 36 V Dual Output: Amplifier and Comparator Output High Accuracy Amplifier: – Offset Voltage: 35 µV (Max) – Offset Voltage Drift: 0.5 µV/°C (Max) – Gain Error: 0.1% (Max) – Gain Error Drift: 10 ppm/°C Available Amplifier Gains: – INA301A1: 20 V/V – INA301A2: 50 V/V – INA301A3: 100 V/V Programmable Alert Threshold Set Through a Single Resistor Total Alert Response Time: 1 µs Open-Drain Output With Latching Mode Package: VSSOP-8 2 Applications • • • • • • Overcurrent Protection Power-Supply Protection Circuit Breakers Computers and Servers Telecom Equipment Battery Management The open-drain alert output can be configured to operate in either a transparent mode where the output status follows the input state or in a latched mode where the alert output is cleared when the latch is reset. The device alert response time is under 1 µs, allowing for quick detection of overcurrent events. This device operates from a single 2.7-V to 5.5-V supply, drawing a maximum supply current of 700 µA. The device is specified over the extended operating temperature range (–40°C to +125°C), and is available in an 8-pin VSSOP package. Device Information PART NUMBER INA301 PACKAGE VSSOP (8) BODY SIZE 3.00 mm × 3.00 mm Typical Application 2.7 V to 5.5 V CBYPASS 0.1 PF RPULL-UP 10 k Supply (0 V to 36 V) VS IN+ + INA301 Microcontroller OUT ADC ALERT INLoad GPIO RESET GND GPIO LIMIT DAC RLIMIT 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. INA301 SBOS713A – SEPTEMBER 2015 – REVISED FEBRUARY 2016 www.ti.com Table of Contents 1 2 3 4 5 6 7 Features .................................................................. Applications ........................................................... Description ............................................................. Revision History..................................................... Pin Configuration and Functions ......................... Specifications......................................................... 1 1 1 2 3 4 6.1 6.2 6.3 6.4 6.5 6.6 4 4 4 4 5 7 Absolute Maximum Ratings ...................................... ESD Ratings.............................................................. Recommended Operating Conditions....................... Thermal Information .................................................. Electrical Characteristics........................................... Typical Characteristics .............................................. Detailed Description ............................................ 13 7.1 Overview ................................................................. 13 7.2 Functional Block Diagram ....................................... 13 7.3 Feature Description................................................. 14 7.4 Device Functional Modes........................................ 19 8 Applications and Implementation ...................... 21 8.1 Application Information .......................................... 21 8.2 Typical Application .................................................. 21 9 Power Supply Recommendations...................... 23 10 Layout................................................................... 23 10.1 Layout Guidelines ................................................. 23 10.2 Layout Example .................................................... 23 11 Device and Documentation Support ................. 24 11.1 11.2 11.3 11.4 Community Resources.......................................... Trademarks ........................................................... Electrostatic Discharge Caution ............................ Glossary ................................................................ 24 24 24 24 12 Mechanical, Packaging, and Orderable Information ........................................................... 24 4 Revision History Changes from Original (September 2015) to Revision A • 2 Page Released to production .......................................................................................................................................................... 1 Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: INA301 INA301 www.ti.com SBOS713A – SEPTEMBER 2015 – REVISED FEBRUARY 2016 5 Pin Configuration and Functions DGK Package 8-Pin VSSOP Top View VS 1 8 IN+ OUT 2 7 IN- LIMIT 3 6 ALERT GND 4 5 RESET Pin Functions PIN NO. NAME I/O DESCRIPTION 1 VS Analog 2 OUT Analog output Power supply, 2.7 V to 5.5 V 3 LIMIT Analog input 4 GND Analog 5 RESET Digital input 6 ALERT Digital output Overlimit alert, active-low, open-drain output 7 IN– Analog input Connect to load side of the shunt resistor 8 IN+ Analog input Connect to supply side of the shunt resistor Output voltage Alert threshold limit input; see the Setting The Current-Limit Threshold section for details on setting the limit threshold Ground Transparent or latch mode selection input Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: INA301 3 INA301 SBOS713A – SEPTEMBER 2015 – REVISED FEBRUARY 2016 www.ti.com 6 Specifications 6.1 Absolute Maximum Ratings over operating free-air temperature range (unless otherwise noted) (1) MIN Supply voltage, VS Differential (VIN+) – (VIN–) (2) MAX UNIT 6 V –40 40 Common-mode (3) GND – 0.3 40 Analog input LIMIT pin GND – 0.3 (VS) + 0.3 V Analog output OUT pin GND – 0.3 (VS) + 0.3 V Digital input RESET pin GND – 0.3 (VS) + 0.3 V Digital output ALERT pin GND – 0.3 6 V 150 °C 150 °C Analog inputs (IN+, IN–) Junction temperature, TJ Storage temperature, Tstg (1) (2) (3) –65 V 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. VIN+ and VIN– are the voltages at the IN+ and IN– pins, respectively. Input voltage can exceed the voltage shown without causing damage to the device if the current at that pin is limited to 5 mA. 6.2 ESD Ratings VALUE V(ESD) (1) (2) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1) ±2000 Charged-device model (CDM), per JEDEC specification JESD22-C101 (2) ±1000 UNIT V JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process. 6.3 Recommended Operating Conditions over operating free-air temperature range (unless otherwise noted) MIN VCM Common-mode input voltage VS Operating supply voltage TA Operating free-air temperature NOM MAX UNIT 12 V 5 V –40 125 °C 6.4 Thermal Information INA301 THERMAL METRIC (1) DGK (MSOP) UNIT 8 PINS RθJA Junction-to-ambient thermal resistance 161.5 °C/W RθJC(top) Junction-to-case (top) thermal resistance 62.3 °C/W RθJB Junction-to-board thermal resistance 81.4 °C/W ψJT Junction-to-top characterization parameter 6.8 °C/W ψJB Junction-to-board characterization parameter 80 °C/W RθJC(bot) Junction-to-case (bottom) thermal resistance N/A °C/W (1) 4 For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report, SPRA953. Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: INA301 INA301 www.ti.com SBOS713A – SEPTEMBER 2015 – REVISED FEBRUARY 2016 6.5 Electrical Characteristics at TA = 25°C, VSENSE = VIN+ – VIN– = 10 mV, VS = 5 V, VIN+ = 12 V, and VLIMIT = 2 V (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT INPUT VCM Common-mode input voltage range VIN Differential input voltage range CMR Common-mode rejection 0 36 VIN = VIN+ – VIN–, INA301A1 0 250 VIN = VIN+ – VIN–, INA301A2 0 100 VIN = VIN+ – VIN–, INA301A3 0 50 INA301A1, VIN+ = 0 V to 36 V, TA = –40ºC to +125ºC 100 110 INA301A2, VIN+ = 0 V to 36 V, TA = –40ºC to +125ºC 106 118 INA301A3, VIN+ = 0 V to 36 V, TA = –40ºC to +125ºC 110 120 V mV dB INA301A1 ±25 ±125 INA301A2 ±15 ±50 INA301A3 ±10 ±35 TA= –40ºC to +125ºC 0.1 0.5 µV/°C ±0.1 ±10 µV/V VOS Offset voltage, RTI (1) dVOS/dT Offset voltage drift, RTI (1) PSRR Power-supply rejection ratio VS = 2.7 V to 5.5 V, VIN+ = 12 V, TA = –40ºC to +125ºC IB Input bias current IB+, IB– 120 µA IOS Input offset current VSENSE = 0 mV ±0.1 µA µV OUTPUT INA301A1 G Gain Gain error 20 INA301A2 50 INA301A3 100 V/V INA301A1, VOUT = 0.5 V to VS – 0.5 V ±0.03% ±0.1% INA301A2, VOUT = 0.5 V to VS – 0.5 V ±0.05% ±0.15% INA301A3, VOUT = 0.5 V to VS – 0.5 V ±0.11% ±0.2% 3 10 TA= –40ºC to 125ºC Nonlinearity error VOUT = 0.5 V to VS – 0.5 V Maximum capacitive load No sustained oscillation ppm/°C ±0.01% 500 pF VOLTAGE OUTPUT Swing to VS power-supply rail RL = 10 kΩ to GND, TA = –40ºC to +125ºC VS – 0.05 VS – 0.1 Swing to GND RL = 10 kΩ to GND, TA = –40ºC to +125ºC VGND + 20 VGND + 30 V mV FREQUENCY RESPONSE BW Bandwidth SR INA301A1 550 INA301A2 500 INA301A3 450 Slew rate kHz 4 V/µs 30 nV/√Hz NOISE, RTI (1) Voltage noise density (1) RTI = referred-to-input. Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: INA301 5 INA301 SBOS713A – SEPTEMBER 2015 – REVISED FEBRUARY 2016 www.ti.com Electrical Characteristics (continued) at TA = 25°C, VSENSE = VIN+ – VIN– = 10 mV, VS = 5 V, VIN+ = 12 V, and VLIMIT = 2 V (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT COMPARATOR tp Total alert propagation delay Input overdrive = 1 mV Slew-rate-limited tp VOUT step = 0.5 V to 4.5 V, VLIMIT = 4 V ILIMIT Limit threshold output current VOS Comparator offset voltage HYS Hysteresis TA = 25ºC 79.7 TA = –40ºC to +125ºC 79.2 0.75 1 1 1.5 80 80.3 80.8 INA301A1 1 INA301A2 1 4 INA301A3 1.5 4.5 INA301A1 20 INA301A2 50 INA301A3 100 µs µA 3.5 mV mV VIH High-level input voltage 1.4 6 VIL Low-level input voltage 0 0.4 V V VOL Alert low-level output voltage IOL = 3 mA 70 300 mV ALERT pin leakage input current VOH = 3.3 V 0.1 1 µA Digital leakage input current 0 ≤ VIN ≤ VS 1 µA POWER SUPPLY VS IQ Operating supply range Quiescent current TA = –40ºC to +125ºC 2.7 VSENSE = 0 mV, TA = 25ºC 5.5 500 TA = –40ºC to +125ºC 650 700 V µA TEMPERATURE RANGE Specified range 6 –40 Submit Documentation Feedback 125 °C Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: INA301 INA301 www.ti.com SBOS713A – SEPTEMBER 2015 – REVISED FEBRUARY 2016 6.6 Typical Characteristics Input Offset Voltage (PV) 100 80 60 40 20 0 -20 -40 -60 -100 -80 Population 100 80 60 40 20 0 -20 -40 -60 -80 -100 Population at TA = 25°C, VS = 5 V, VIN+ = 12 V, and alert pullup resistor = 10 kΩ (unless otherwise noted) Input Offset Voltage (PV) Figure 1. Input Offset Voltage Distribution (INA301A1) Figure 2. Input Offset Voltage Distribution (INA301A2) 60 INA301A1 INA301A2 INA301A3 Population Offset Voltage (PV) 40 20 100 80 60 40 20 0 -20 -40 -60 -80 -100 0 -20 -50 -25 0 25 50 75 Temperature (qC) 100 125 150 Input Offset Voltage (PV) Figure 4. Input Offset Voltage vs Temperature 5 4 3 2 1 0 -1 -2 -3 -4 -5 10 8 6 4 2 0 -2 -4 -6 -8 -10 Population Population Figure 3. Input Offset Voltage Distribution (INA301A3) CMRR (PV/V) CMRR (PV/V) Figure 5. Common-Mode Rejection Ratio Distribution (INA301A1) Figure 6. Common-Mode Rejection Ratio Distribution (INA301A2) Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: INA301 7 INA301 SBOS713A – SEPTEMBER 2015 – REVISED FEBRUARY 2016 www.ti.com Typical Characteristics (continued) at TA = 25°C, VS = 5 V, VIN+ = 12 V, and alert pullup resistor = 10 kΩ (unless otherwise noted) 3 2.5 Population CMRR (Pv/v) 2 INA301A1 INA301A2 INA301A3 1.5 1 0.5 0 -1 -50 3 2.5 2 1.5 1 0 0.5 -1 -0.5 -1.5 -2 -3 -2.5 -0.5 -25 0 25 50 75 Temperature (qC) 100 125 150 CMRR (PV/V) Figure 7. Common-Mode Rejection Ratio Distribution (INA301A3) Figure 8. Common-Mode Rejection Ratio vs Temperature 140 INA301A1 INA301A2 INA301A3 Population CMRR (dB) 120 100 0.1 0.08 0.06 0.04 0.02 0 1M -0.02 100k -0.04 1k 10k Frequency (Hz) -0.06 100 -0.1 60 10 -0.08 80 Gain Error (%) Figure 10. Gain Error Distribution (INA301A1) Gain Error (%) 0.2 0.16 0.12 0.08 0.04 0 -0.04 -0.08 -0.12 Gain Error (%) Figure 11. Gain Error Distribution (INA301A2) 8 -0.16 -0.2 Population 0.1 0.08 0.06 0.04 0.02 0 -0.02 -0.04 -0.06 -0.08 -0.1 Population Figure 9. Common-Mode Rejection Ratio vs Frequency Figure 12. Gain Error Distribution (INA301A3) Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: INA301 INA301 www.ti.com SBOS713A – SEPTEMBER 2015 – REVISED FEBRUARY 2016 Typical Characteristics (continued) at TA = 25°C, VS = 5 V, VIN+ = 12 V, and alert pullup resistor = 10 kΩ (unless otherwise noted) 0.5 50 INA301A1 INA301A2 INA301A3 0.4 0.3 40 30 0.1 Gain (dB) Gain Error (%) 0.2 0 -0.1 -0.2 20 10 0 -0.3 INA301A1 INA301A2 INA301A3 -10 -0.4 -0.5 -50 -20 -25 0 25 50 75 Temperature (qC) 100 125 150 1 10 Figure 13. Gain Error vs Temperature 1k 10k Frequency (Hz) 100k 1M 10M Figure 14. Gain vs Frequency VS 140 Output Voltage Swing (V) 120 100 PSRR (dB) 100 80 60 VS - 1 VS - 2 GND + 3 GND + 2 125ºC 25ºC -40ºC GND + 1 40 GND 20 1 10 100 1k 10k Frequency (Hz) 100k 1M 0 10M 4 6 8 10 12 14 Output Current (mA) Figure 16. Output Voltage Swing vs Output Current Figure 15. Power-Supply Rejection Ratio vs Frequency 150 250 200 120 Input Bias Current (PA) Input Bias Current (PA) 2 150 100 50 90 60 30 0 -50 0 0 5 10 15 20 25 30 Common-Mode Voltage (V) 35 40 Figure 17. Input Bias Current vs Common-Mode Voltage (VS = 5 V) 0 5 10 15 20 25 30 Common-Mode Voltage (V) 35 40 Figure 18. Input Bias Current vs Common-Mode Voltage (VS = 0 V) Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: INA301 9 INA301 SBOS713A – SEPTEMBER 2015 – REVISED FEBRUARY 2016 www.ti.com Typical Characteristics (continued) at TA = 25°C, VS = 5 V, VIN+ = 12 V, and alert pullup resistor = 10 kΩ (unless otherwise noted) 145 600 140 Quiescent Current (PA) Input Bias Current (PA) 550 135 130 125 120 115 110 500 450 400 350 105 100 -50 -25 0 25 50 75 Temperature (qC) 100 125 300 2.7 150 Figure 19. Input Bias Current vs Temperature 3.6 3.9 4.2 4.5 4.8 Supply Voltage (V) 5.1 5.4 5.7 Input-Referred Voltage Noise (nV/—Hz) 35 520 Quiescent Current (PA) 3.3 Figure 20. Quiescent Current vs Supply Voltage 540 500 480 460 440 420 -50 3 30 25 20 15 10 INA301A1 INA301A2 INA301A3 5 0 -25 0 25 50 75 Temperature (qC) 100 125 150 1 100 1k 10k Frequency (Hz) 1M Input Output Output (1 V/div) Referred-to-Input Voltage Noise (200 nV/div) 100k Figure 22. Input-Referred Voltage Noise vs Frequency Input (200 mV/div) Figure 21. Quiescent Current vs Temperature 10 Time (1 s/div) Time (1 Ps/div) Figure 23. 0.1-Hz to 10-Hz Voltage Noise (Referred-to-Input) 10 Figure 24. Voltage Output Rising Step Response (4-VPP Output Step) Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: INA301 INA301 www.ti.com SBOS713A – SEPTEMBER 2015 – REVISED FEBRUARY 2016 Typical Characteristics (continued) VOUT (60 mV/div) Output (1 V/div) Input Output Common-Mode Voltage (10 V/div) Input (200 mV/div) at TA = 25°C, VS = 5 V, VIN+ = 12 V, and alert pullup resistor = 10 kΩ (unless otherwise noted) VCM VOUT Time (1 Ps/div) Time (2 Ps/div) Figure 25. Voltage Output Falling Step Response (4-VPP Output Step) Figure 26. Common-Mode Voltage Transient Response 80.8 Voltage (2 V/div) Limit Current Source (PA) 80.6 VSUPPLY VOUT 80.4 80.2 80 79.8 79.6 79.4 79.2 -50 Time (5 Ps/div) 0 25 50 75 Temperature (qC) 100 125 150 Figure 28. Limit Current Source vs Temperature VIN * 20 V/V Alert VLIMIT Voltage (0.5 V/div) Figure 27. Start-Up Response Voltage (0.5 V/div) -25 VIN * 50 V/V Alert VLIMIT Time (200 ns/div) Time (200 ns/div) Figure 29. Total Propagation Delay (INA301A1) Figure 30. Total Propagation Delay (INA301A2) Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: INA301 11 INA301 SBOS713A – SEPTEMBER 2015 – REVISED FEBRUARY 2016 www.ti.com Typical Characteristics (continued) at TA = 25°C, VS = 5 V, VIN+ = 12 V, and alert pullup resistor = 10 kΩ (unless otherwise noted) 1,000 Propagation Delay (ns) Voltage (0.5 V/div) 800 VIN * 100 V/V Alert VLIMIT 600 400 200 0 -50 Time (200 ns/div) 0 25 50 75 Temperature (qC) 100 125 150 Figure 32. Comparator Propagation Delay vs Temperature (VOD = 1 mV) Figure 31. Total Propagation Delay (INA301A3) 120 120 100 100 80 80 Hysteresis (mV) Low-Level Output Voltage (mV) -25 60 40 INA301A1 INA301A2 INA301A3 60 40 20 20 0 -50 0 0 0.5 1 1.5 2 2.5 3 3.5 4 Low-Level Output Current (mA) 4.5 5 Figure 33. Comparator Alert VOL vs IOL -25 0 25 50 75 Temperature (qC) 100 125 150 Figure 34. Hysteresis vs Temperature Voltage (2 V/div) Reset Alert Time (2 Ps/div) Figure 35. Comparator Reset Response 12 Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: INA301 INA301 www.ti.com SBOS713A – SEPTEMBER 2015 – REVISED FEBRUARY 2016 7 Detailed Description 7.1 Overview The INA301 is a 36-V common-mode, zero-drift topology, current-sensing amplifier that can be used in both lowside and high-side configurations. These specially-designed, current-sensing amplifiers are able to accurately measure voltages developed across current-sensing resistors (also known as current-shunt resistors) on common-mode voltages that far exceed the supply voltage powering the device. Current can be measured on input voltage rails as high as 36 V, and the device can be powered from supply voltages as low as 2.7 V. The device can also withstand the full 36-V common-mode voltage at the input pins when the supply voltage is removed without causing damage. The zero-drift topology enables high-precision measurements with maximum input offset voltages as low as 35 μV with a temperature contribution of only 0.5 μV/°C over the full temperature range of –40°C to +125°C. The low total offset voltage of the INA301 enables smaller current-sense resistor values to be used, and allows for a more efficient system operation without sacrificing measurement accuracy resulting from the smaller input signal. The INA301 uses a single external resistor to allow for a simple method of setting the corresponding current threshold level for the device to use for out-of-range comparison. Combining the precision measurement of the current-sense amplifier and the on-board comparator enables an all-in-one overcurrent detection device. This combination creates a highly-accurate solution that is capable of fast detection of out-of-range conditions and allows the system to take corrective actions to prevent potential component or system-wide damage. 7.2 Functional Block Diagram 2.7 V to 5.5 V CBYPASS 0.1 PF Power Supply (0 V to 36 V) VS IN+ INA301 + RPULL-UP 10k OUT Gain = 20, 50, 100 INLoad ALERT + RESET LIMIT GND RSET Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: INA301 13 INA301 SBOS713A – SEPTEMBER 2015 – REVISED FEBRUARY 2016 www.ti.com 7.3 Feature Description 7.3.1 Alert Output The device ALERT pin is an active-low, open-drain output that is designed to be pulled low when the input conditions are detected to be out-of-range. This open-drain output pin is recommended to include a 10-kΩ, pullup resistor to the supply voltage. This open-drain pin can be pulled up to a voltage beyond the supply voltage, VS, but must not exceed 5.5 V. Figure 36 shows the alert output response of the internal comparator. When the output voltage of the amplifier is lower than the voltage developed at the LIMIT pin, the comparator output is in the default high state. When the amplifier output voltage exceeds the threshold voltage set at the LIMIT pin, the comparator output becomes active and pulls low. This active low output indicates that the measured signal at the amplifier input has exceeded the programmed threshold level, indicating an overcurrent or out-of-range condition has occurred. 6 VOUT VLIMIT ALERT 5 Voltage (V) 4 3 2 1 0 ±1 Time (5 ms/div) C001 Figure 36. Overcurrent Alert Response 7.3.2 Alert Mode The device has two output operating modes, transparent and latched, that are selected based on the RESET pin setting. These modes change how the ALERT pin responds following an alert when the overcurrent condition is removed. 7.3.2.1 Transparent Output Mode The device is set to transparent mode when the RESET pin is pulled low, thus allowing the output alert state to change and follow the input signal with respect to the programmed alert threshold. For example, when the differential input signal rises above the alert threshold, the alert output pin is pulled low. As soon as the differential input signal drops below the alert threshold, the output returns to the default high output state. A common implementation using the device in transparent mode is to connect the ALERT pin to a hardware interrupt input on a microcontroller. As soon as an overcurrent condition is detected and the ALERT pin is pulled low, the controller interrupt pin detects the output state change and can begin making changes to the system operation required to address the overcurrent condition. Under this configuration, the ALERT pin transition from high to low is captured by the microcontroller so the output can return to the default high state when the overcurrent event is removed. 7.3.2.2 Latch Output Mode Some applications do not have the functionality available to continuously monitor the state of the output ALERT pin to detect an overcurrent condition as described in the Transparent Output Mode section. A typical example of this application is a system that is only able to poll the ALERT pin state periodically to determine if the system is functioning correctly. If the device is set to transparent mode in this type of application, the state change of the ALERT pin can be missed when ALERT is pulled low to indicate an out-of-range event if the out-of-range condition does not appear during one of these periodic polling events. Latch mode is specifically intended to accommodate these applications. 14 Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: INA301 INA301 www.ti.com SBOS713A – SEPTEMBER 2015 – REVISED FEBRUARY 2016 Feature Description (continued) The device is placed into the corresponding output modes based on the signal connected to RESET, as shown in Table 1. The difference between latch mode and transparent mode is how the alert output responds when an overcurrent event ends. In transparent mode (RESET = low), when the differential input signal drops below the limit threshold level after the ALERT pin asserts because of an overcurrent event, the ALERT pin state returns to the default high setting to indicate that the overcurrent event has ended. Table 1. Output Mode Settings OUTPUT MODE RESET PIN SETTING Transparent mode RESET = low Latch mode RESET = high In latch mode (RESET = high), when an overlimit condition is detected and the ALERT pin is pulled low, the ALERT pin does not return to the default high state when the differential input signal drops below the alert threshold level. In order to clear the alert, the RESET pin must be pulled low for at least 100 ns. Pulling the RESET pin low allows the ALERT pin to return to the default high level provided that the differential input signal has dropped below the alert threshold. If the input signal is still above the threshold limit when the RESET pin is pulled low, the ALERT pin remains low. When the alert condition is detected by the system controller, the RESET pin can be set back to high in order to place the device back in latch mode. The latch and transparent modes are represented in Figure 37. In Figure 37, when VIN drops back below the VLIMIT threshold for the first time, the RESET pin is pulled high. With the RESET pin is pulled high, the device is set to latch mode so that the alert output state does not return high when the input signal drops below the VLIMIT threshold. Only when the RESET pin is pulled low does the ALERT pin return to the default high level, thus indicating that the input signal is below the limit threshold. When the input signal drops below the limit threshold for the second time, the RESET pin is already pulled low. The device is set to transparent mode at this point and the ALERT pin is pulled back high as soon as the input signal drops below the alert threshold. VLIMIT VIN (VIN+ - VIN-) 0V Latch Mode RESET Transparent Mode Alert Clears ALERT Alert Does Not Clear Figure 37. Transparent versus Latch Mode 7.3.3 Setting The Current-Limit Threshold The INA301 determines if an overcurrent event is present by comparing the amplified measured voltage developed across the current-sensing resistor to the corresponding signal developed at the LIMIT pin. The threshold voltage for the LIMIT pin can be set using a single external resistor or by connecting an external voltage source to the LIMIT pin. Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: INA301 15 INA301 SBOS713A – SEPTEMBER 2015 – REVISED FEBRUARY 2016 www.ti.com 7.3.3.1 Resistor-Controlled Current Limit The typical approach for setting the limit threshold voltage is to connect a resistor from the LIMIT pin to ground. The value of this resistor, RLIMIT, is chosen in order to create a corresponding voltage at the LIMIT pin equivalent to the output voltage, VOUT, when the maximum desired load current is flowing through the current-sensing resistor. An internal 80-µA current source is connected to the LIMIT pin to create a corresponding voltage used to compare to the amplifier output voltage, depending on the value of the RLIMIT resistor. In the equations from Table 2, VTRIP represents the overcurrent threshold that the device is programmed to monitor for and VLIMIT is the programmed signal set to detect the VTRIP level. Table 2. Calculating the Limit Threshold Setting Resistor, RLIMIT PARAMETER EQUATION VTRIP VOUT at the desired current trip value VLIMIT Threshold limit voltage RLIMIT Calculate the threshold limit-setting resistor ILOAD × RSENSE x Gain VLIMIT = VTRIP ILIMIT × RLIMIT VLIMIT / ILIMIT VLIMIT / 80 µA 7.3.3.1.1 Resistor-Controlled Current Limit: Example For example, if the current level indicating an out-of-range condition is present is 20 A and the current-sense resistor value is 10 mΩ, then the input threshold signal is 200 mV. The INA301A1 has a gain of 20 so the resulting output voltage at the 20-A input condition is 4 V. The value for RLIMIT is selected to allow the device to detect to this 20-A threshold, indicating an overcurrent event has occurred. When the INA301 detects this out-ofrange condition, the ALERT pin asserts and pulls low. For this example, the value of RLIMIT to detect a 4-V level is calculated to be 50 kΩ, as shown in Table 3. Table 3. Calculating the Limit Threshold Setting Resistor, RLIMIT: Example PARAMETER EQUATION VTRIP VOUT at the desired current trip value VLIMIT Threshold limit voltage RLIMIT Calculate the threshold limit-setting resistor ILOAD × RSENSE x Gain 20 A x 10 mΩ x 20 V/V = 4 V VLIMIT = VTRIP ILIMIT × RLIMIT VLIMIT / ILIMIT 4 V / 80 µA = 50 kΩ 7.3.3.2 Voltage-Source-Controlled Current Limit The second method for setting the limit voltage is to connect the LIMIT pin to a programmable digital-to-analog converter (DAC) or other external voltage source. The benefit of this method is the ability to adjust the currentlimit threshold to account for different threshold voltages that are used for different system operating conditions. For example, this method can be used in a system that has one current-limit threshold level that must be monitored during a power-up sequence but different threshold levels that must be monitored during other system operating modes. In Table 4, VTRIP represents the overcurrent threshold that the device is programmed to monitor for and VSOURCE is the programmed signal set to detect the VTRIP level. Table 4. Calculating the Limit Threshold Voltage Source, VSOURCE PARAMETER EQUATION VTRIP VOUT at the desired current trip value ILOAD × RSENSE × Gain VSOURCE Program the threshold limit voltage 16 Submit Documentation Feedback VSOURCE = VTRIP Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: INA301 INA301 www.ti.com SBOS713A – SEPTEMBER 2015 – REVISED FEBRUARY 2016 7.3.4 Selecting a Current-Sensing Resistor The device measures the differential voltage developed across a resistor when current flows through the component to determine if the current being monitored exceeds a defined limit. This resistor is commonly referred to as a current-sensing resistor or a current-shunt resistor, with each term commonly used interchangeably. The flexible design of the device allows for measuring a wide differential input signal range across this current-sensing resistor. Selecting the value of this current-sensing resistor is based primarily on two factors: the required accuracy of the current measurement and the allowable power dissipation across the current-sensing resistor. Larger voltages developed across this resistor allow for more accurate measurements to be made. Amplifiers have fixed internal errors that are largely dominated by the inherent input offset voltage. When the input signal decreases, these fixed internal amplifier errors become a larger portion of the measurement and increase the uncertainty in the measurement accuracy. When the input signal increases, the measurement uncertainty is reduced because the fixed errors are a smaller percentage of the signal being measured. Therefore, the use of larger value currentsensing resistors inherently improves the measurement accuracy. However, a system design trade-off must be evaluated through use of larger input signals for improving the measurement accuracy. Increasing the current sense resistor value results in an increase in power dissipation across the current-sensing resistor. Increasing the value of the current-shunt resistor increases the differential voltage developed across the resistor when current passes through the component. This increase in voltage across the resistor increases the power that the resistor must be able to dissipate. Decreasing the value of the current-shunt resistor value reduces the power dissipation requirements of the resistor, but increases the measurement errors resulting from the decreased input signal. Selecting the optimal value for the shunt resistor requires factoring both the accuracy requirement for the specific application and the allowable power dissipation of this component. An increasing number of very low ohmic-value resistors are becoming more widely available with values reaching down as low as 200 µΩ or lower with power dissipations of up to 5 W that enable large currents to be accurately monitored with sensing resistors. 7.3.4.1 Selecting a Current-Sensing Resistor: Example In this example, the trade-offs involved in selecting a current-sensing resistor are discussed. This example requires 2.5% accuracy for detecting a 10-A overcurrent event where only 250 mW is allowable for the dissipation across the current-sensing resistor at the full-scale current level. Although the maximum power dissipation is defined as 250 mW, a lower dissipation is preferred to improve system efficiency. Some initial assumptions are made that are used in this example: the limit-setting resistor (RLIMIT) is a 1% component and the maximum tolerance specification for the internal threshold setting current source (0.5%) is used. Given the total error budget of 2.5%, up to 1% of error is available to be attributed to the measurement error of the device under these conditions. Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: INA301 17 INA301 SBOS713A – SEPTEMBER 2015 – REVISED FEBRUARY 2016 www.ti.com As shown in Table 5, the maximum value calculated for the current-sensing resistor with these requirements is 2.5 mΩ. Although this value satisfies the maximum power dissipation requirement of 250 mW, headroom is available from the 2.5% maximum total overcurrent detection error to reduce the value of the current-sensing resistor and reduce the power dissipation further. Selecting a 1.5-mΩ, current-sensing resistor value offers a good tradeoff for reducing the power dissipation in this scenario by approximately 40% and still remaining within the accuracy region. Table 5. Calculating the Current-Sensing Resistor, RSENSE PARAMETER EQUATION VALUE UNIT IMAX Maximum current 10 A PD_MAX Maximum allowable power dissipation 250 mW RSENSE_MAX Maximum allowable RSENSE 2.5 mΩ VOS Offset voltage 150 µV VOS_ERROR Initial offset voltage error EG Gain error ERRORTOTAL Total measurement error PD_MAX / IMAX2 (VOS / (RSENSE_MAX × IMAX ) × 100 0.6% 0.25% √(VOS_ERROR2 + EG2) 0.65% Allowable current threshold accuracy 2.5% ERRORINITIAL Initial threshold error ILIMIT Tolerance + RLIMIT Tolerance ERRORAVAILABLE Maximum allowable measurement error Maximum Error – ERRORINITIAL 2 EG2) 1.5% 1% VOS_ERROR_MAX Maximum allowable offset error √(ERRORAVAILABLE – VDIFF_MIN Minimum differential voltage VOS / VOS_ERROR_MAX (1%) 15 mV RSENSE_MIN Minimum sense resistor value VDIFF_MIN / IMAX 1.5 mΩ PD_MIN Lowest possible power dissipation RSENSE_MIN × IMAX2 150 mW 0.97% 7.3.5 Hysteresis The on-board comparator in the INA301 is designed to reduce the possibility of oscillations in the alert output when the measured signal level is near the overlimit threshold level because of noise. When the output voltage (VOUT) exceeds the voltage developed at the LIMIT pin, the ALERT pin is asserted and pulls low. The output voltage must drop below the LIMIT pin threshold voltage by the gain-dependent hysteresis level in order for the ALERT pin to de-assert and return to the nominal high state, as shown in Figure 38. ALERT Alert Output VOUT VLIMIT - Hysteresis VLIMIT Figure 38. Typical Comparator Hysteresis 18 Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: INA301 INA301 www.ti.com SBOS713A – SEPTEMBER 2015 – REVISED FEBRUARY 2016 7.4 Device Functional Modes 7.4.1 Input Filtering External system noise can significantly affect the ability of a comparator to accurately measure and detect whether input signals exceed the reference threshold levels, thus reliably indicating an overrange condition. The most obvious effect that external noise can have on the operation of a comparator is to cause a false alert condition. If a comparator detects a large noise transient coupled into the signal, the device can easily interpret this transient as an overrange condition. External filtering can help reduce the amount of noise that reaches the comparator and reduce the likelihood of a false alert from occurring. The tradeoff to adding this noise filter is that the alert response time is increased because of the input signal being filtered as well as the noise. Figure 39 shows the implementation of an input filter for the device. 2.7 V to 5.5 V CBYPASS 0.1 PF Supply (0 V to 36 V) RPULL-UP 10 k VS IN+ RFILTER ”10 CFILTER INA301 + OUT ALERT INLoad RESET LIMIT GND RLIMIT Figure 39. Input Filter Limiting the amount of input resistance used in this filter is important because this resistance can have a significant affect on the input signal that reaches the device input pins resulting from the device input bias currents. A typical system implementation involves placing the current-sensing resistor very near the device so the traces are very short and the trace impedance is very small. This layout helps reduce the ability of coupling additional noise into the measurement. Under these conditions, the characteristics of the input bias currents have minimal affect on device performance. As illustrated in Figure 40, the input bias currents increase in opposite directions when the differential input voltage increases. This increase results from the design of the device that allows common-mode input voltages to far exceed the device supply voltage range. With input filter resistors now placed in series with these unequal input bias currents, there are unequal voltage drops developed across these input resistors. The difference between these two drops appears as an added signal that (in this case) subtracts from the voltage developed across the current-sensing resistor, thus reducing the signal that reaches the device input pins. Smaller value input resistors reduce this effect of signal attenuation to allow for a more accurate measurement. Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: INA301 19 INA301 SBOS713A – SEPTEMBER 2015 – REVISED FEBRUARY 2016 www.ti.com Device Functional Modes (continued) 225 Input Bias Current (µA) 200 175 150 125 100 75 50 25 0 0 50 100 150 200 Differential Input Voltage (mV) 250 C002 Figure 40. Input Bias Current vs Differential Input Voltage For example, with a differential voltage of 10 mV developed across a current-sensing resistor and using 20-Ω resistors, the differential signal that actually reaches the device is 9.85 mV. A measurement error of 1.5% is created as a result of these external input filter resistors. Using 10-Ω input filter resistors instead of the 20-Ω resistors reduces this added error from 1.5% down to 0.75%. 7.4.2 Using The INA301 with Common-Mode Transients Above 36 V With a small amount of additional circuitry, the device can be used in circuits subject to transients higher than 36 V. Use only zener diodes or zener-type transient absorbers (sometimes referred to as transzorbs). Any other type of transient absorber has an unacceptable time delay. Start by adding a pair of resistors, as shown in Figure 41, as a working impedance for the zener diode. Keeping these resistors as small as possible is best, preferably 10 Ω or less. Larger values can be used with an additional induced error resulting from a reduced signal that actually reaches the device input pins. Because this circuit limits only short-term transients, many applications are satisfied with a 10-Ω resistor along with conventional zener diodes of the lowest power rating available. This combination uses the least amount of board space. These diodes can be found in packages as small as SOT-523 or SOD-523. 2.7 V to 5.5 V CBYPASS 0.1 PF Supply (0 V to 36 V) RPULL-UP 10k VS IN+ INA301 + OUT RPROTECT ”10 ALERT INLoad RESET LIMIT GND RLIMIT Figure 41. Transient Protection 20 Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: INA301 INA301 www.ti.com SBOS713A – SEPTEMBER 2015 – REVISED FEBRUARY 2016 8 Applications 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. 8.1 Application Information The INA301 is designed to enable easy configuration for detecting overcurrent conditions in an application. This device is individually targeted towards unidirectional overcurrent detection of a single threshold. However, this device can also be paired with additional devices and circuitry to create more complex monitoring functional blocks. 8.2 Typical Application CBYPASS 0.1 PF 2.7 V to 5.5 V RPULL-UP 10 k VS IN+ + OUT IN- Power Supply (0 V to 36 V) OCP+ ALERT LIMIT GND RLIMIT Current Output CBYPASS 0.1 PF 2.7 V to 5.5 V Load RPULL-UP 10 k IN+ + VS IN- OUT OCP- ALERT LIMIT GND RLIMIT Figure 42. Bidirectional Application 8.2.1 Design Requirements Although the device is only able to measure current through a current-sensing resistor flowing in one direction, a second INA301 can be used to create a bidirectional monitor. Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: INA301 21 INA301 SBOS713A – SEPTEMBER 2015 – REVISED FEBRUARY 2016 www.ti.com Typical Application (continued) 8.2.2 Detailed Design Procedure With the input pins of a second device reversed across the same current-sensing resistor, the second device is now able to detect current flowing in the other direction relative to the first device; see Figure 42. The outputs of each device connect to an AND gate to detect if either of the limit threshold levels are exceeded. As shown in Table 6, the output of the AND gate is high if neither overcurrent limit thresholds are exceeded. A low output state of the AND gate indicates that either the positive overcurrent limit or the negative overcurrent limit are surpassed. Table 6. Bidirectional Overcurrent Output Status OCP STATUS OUTPUT OCP+ 0 OCP– 0 No OCP 1 8.2.3 Application Curve Input (5 mV/div) Alert Output (1 V/div) Figure 43 shows two INA301 devices being used in a bidirectional configuration and an output control circuit to detect if one of the two alerts is exceeded. Positive Limit 0V Negtive Limit Time (5 ms/div) Figure 43. Bidirectional Application Curve 22 Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: INA301 INA301 www.ti.com SBOS713A – SEPTEMBER 2015 – REVISED FEBRUARY 2016 9 Power Supply Recommendations The device input circuitry can accurately measure signals on common-mode voltages beyond the power-supply voltage, VS. For example, the voltage applied to the VS power-supply pin can be 5 V, whereas the load powersupply voltage being monitored (VCM) can be as high as 36 V. Note also that the device can withstand the full –0.3 V to 36 V range at the input pins, regardless of whether the device has power applied or not. Power-supply bypass capacitors are required for stability and must be placed as closely as possible to the supply and ground pins of the device. A typical value for this supply bypass capacitor is 0.1 µF. Applications with noisy or high-impedance power supplies can require additional decoupling capacitors to reject power-supply noise. 10 Layout 10.1 Layout Guidelines • • • 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. Make the connection of RLIMIT to the ground pin as direct as possible to limit additional capacitance on this node. Routing this connection must be limited to the same plane if possible to avoid vias to internal planes. If the routing can not be made on the same plane and must pass through vias, ensure that a path is routed from RLIMIT back to the ground pin and that RLIMIT is not simply connected directly to a ground plane. The open-drain output pin is recommended to be pulled up to the supply voltage rail through a 10-kΩ pullup resistor. 10.2 Layout Example RSHU NT Power Sup ply Loa d 5 7 ALE RT RESET 6 IN- 8 Aler t Output IN+ RPUL L-UP VIA to Gro und Plan e CBYPASS 1 2 3 4 INA301 VS OUT LIMIT GND Sup ply Voltage VIA to Gro und Plan e RLIMIT Output Voltage NOTE: Connect the limit resistor directly to the GND pin. Figure 44. Recommended Layout Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: INA301 23 INA301 SBOS713A – SEPTEMBER 2015 – REVISED FEBRUARY 2016 www.ti.com 11 Device and Documentation Support 11.1 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. 11.2 Trademarks E2E is a trademark of Texas Instruments. All other trademarks are the property of their respective owners. 11.3 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. 11.4 Glossary SLYZ022 — TI Glossary. This glossary lists and explains terms, acronyms, and definitions. 12 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. 24 Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: INA301 PACKAGE OPTION ADDENDUM www.ti.com 10-Dec-2020 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (°C) Device Marking (3) (4/5) (6) INA301A1IDGKR ACTIVE VSSOP DGK 8 2500 RoHS & Green NIPDAUAG Level-2-260C-1 YEAR -40 to 125 ZGD6 INA301A1IDGKT ACTIVE VSSOP DGK 8 250 RoHS & Green NIPDAUAG Level-2-260C-1 YEAR -40 to 125 ZGD6 INA301A2IDGKR ACTIVE VSSOP DGK 8 2500 RoHS & Green NIPDAUAG Level-2-260C-1 YEAR -40 to 125 ZGI6 INA301A2IDGKT ACTIVE VSSOP DGK 8 250 RoHS & Green NIPDAUAG Level-2-260C-1 YEAR -40 to 125 ZGI6 INA301A3IDGKR ACTIVE VSSOP DGK 8 2500 RoHS & Green NIPDAUAG Level-2-260C-1 YEAR -40 to 125 ZGH6 INA301A3IDGKT ACTIVE VSSOP DGK 8 250 RoHS & Green NIPDAUAG Level-2-260C-1 YEAR -40 to 125 ZGH6 (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) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
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