FEATURES FUNCTIONAL BLOCK DIAGRAM VDD Window monitoring with minimum processor I/O Individually monitoring N rails with only N + 1 processor I/O 400 mV, ± 0.275% threshold at VDD = 3.3 V, 25°C Supply range: 1.7 V to 5.5 V Low quiescent current: 17 μA maximum at 125°C Input range includes ground Internal hysteresis: 9.2 mV typical Low input bias current: 2.5 nA maximum Open-drain outputs Power good indication output Designated over voltage indication output Low profile (1 mm), 6-lead TSOT package ADCMP671 PWRGD INH UV 400mV OV OV INL 10160-001 Data Sheet Low Power, Adjustable UV and OV Monitor with 400 mV, ±0.275% Reference ADCMP671 GND Figure 1. APPLICATIONS Supply voltage monitoring Li-Ion monitoring Portable applications Handheld instruments GENERAL DESCRIPTION The ADCMP671 is available in 6-lead TSOT package. The device operates over the −40°C to +125°C temperature range. 404 INH1 INL1 402 INH2 INL2 400 RISING INPUT 398 396 394 FALLING INPUT 392 390 388 TWO TYPICAL PARTS COMPARATOR A AND COMPARATOR B VDD = 5V 386 –40 –20 0 20 40 60 80 100 TEMPERATURE (°C) 120 10160-002 THRESHOLD VOLTAGE (mV) The ADCMP671 voltage monitor consists of two low power, high accuracy comparators and reference circuits. It operates on a supply voltage from 1.7 V to 5.5 V and draws 17 μA maximum, making it suitable for low power system monitoring and portable applications. The part is designed to monitor and report supply undervoltage and overvoltage fault. The low input bias current and voltage reference allows resistor adjustable UV and OV threshold down to 400 mV. The ADCMP671 has two opendrain outputs: the PWRGD output indicates that the supply is within the UV and OV window, and the OV output indicates that the supply is overvoltage. This output combination allows users to window monitor N supplies with an N + 1 processor input/output (I/O). Each output is guaranteed to sink greater than 5 mA over temperature. Figure 2. Comparator Thresholds vs. Temperature Rev. 0 Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 ©2011 Analog Devices, Inc. All rights reserved. ADCMP671 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Typical Performance Characteristics ..............................................9 Applications....................................................................................... 1 Applications Information .............................................................. 14 Functional Block Diagram .............................................................. 1 Comparators and Internal Reference ...................................... 14 General Description ......................................................................... 1 Power Supply............................................................................... 14 Revision History ............................................................................... 2 Inputs ........................................................................................... 14 Specifications..................................................................................... 3 Hysteresis..................................................................................... 14 Absolute Maximum Ratings............................................................ 7 Voltage Monitoring Scheme ..................................................... 14 Thermal Resistance ...................................................................... 7 Outputs ........................................................................................ 15 ESD Caution.................................................................................. 7 Outline Dimensions ....................................................................... 16 Pin Configuration and Function Descriptions............................. 8 Ordering Guide .......................................................................... 16 REVISION HISTORY 11/11—Revision 0: Initial Version Rev. 0 | Page 2 of 16 Data Sheet ADCMP671 SPECIFICATIONS VDD = 1.7 V to 5.5 V, TA = 25°C, unless otherwise noted. Table 1. Parameter THRESHOLDS 1 Rising Input Threshold Voltage (VTH(R)) Falling Input Threshold Voltage(VTH(F)) Rising Input Threshold Voltage Accuracy Falling Input Threshold Voltage Accuracy Hysteresis = VTH(R) − VTH(F) INPUT CHARACTERISTICS Input Bias Current OPEN-DRAN OUTPUTS Output Low Voltage 2 Output Leakage Current 3 DYNAMIC PERFORMANCE2, 4 High-to-Low Propagation Delay Low-to-High Propagation Delay Output Rise Time Output Fall Time POWER SUPPLY Supply Current 5 Min Typ Max Unit Test Conditions/Comments 396.6 399.3 398.5 387 389.2 388.5 400.4 400.4 400.4 391 391 391 9.2 mV mV mV mV mV mV % % mV VDD = 1.7 V VDD = 3.3 V VDD = 5.5 V VDD = 1.7 V VDD = 3.3 V VDD = 5.5 V VDD = 3.3 V VDD = 3.3 V 7.8 404.3 401.5 402.2 395.4 392.9 393.2 ±0.275 ±0.475 11.1 0.01 0.01 1 1 nA nA VDD = 1.7 V, VIN = VDD VDD = 1.7 V, VIN = 0.1 V 140 130 0.01 0.01 200 200 0.1 0.1 mV mV μA μA VDD = 1.7 V, IOUT = 3 mA VDD = 5.5 V, IOUT = 5 mA VDD = 1.7 V, VOUT = VDD VDD = 1.7 V, VOUT = 5.5 V μs μs μs μs VDD = 5.5 V, VOL = 400 mV VDD = 5.5 V, VOH = 0.9 × VDD VDD = 5.5 V, VOUT = (0.1 to 0.9) × VDD VDD = 5.5 V, VOUT = (0.1 to 0.9) × VDD μA μA VDD = 1.7 V VDD = 5.5 V 10 8 0.5 0.07 5.7 6.5 10 11 1 RL = 100 kΩ, VOUT = 2 V swing. VIN = 10 mV input overdrive. 3 VIN = 40 mV overdrive. 4 RL = 10 kΩ. 5 No load current. 2 Rev. 0 | Page 3 of 16 ADCMP671 Data Sheet VDD = 1.7 V to 5.5 V, 0°C ≤ TA ≤ 70°C, unless otherwise noted. Table 2. Parameter THRESHOLDS 1 Rising Input Threshold Voltage (VTH(R)) Falling Input Threshold Voltage (VTH(F)) Rising Input Threshold Voltage Accuracy Falling Input Threshold Voltage Accuracy Hysteresis = VTH(R) − VTH(F) INPUT CHARACTERISTICS Input Bias Current OPEN-DRAIN OUTPUTS Output Low Voltage 2 Output Leakage Current 3 POWER SUPPLY Supply Current 4 Min 395.3 397.3 396.8 385.8 386.2 385.8 6.8 Typ Max Unit Test Conditions/Comments 405.3 403.3 403.8 397.3 394.8 395.2 ±0.75 ±1.1 12.2 mV mV mV mV mV mV % % mV VDD = 1.7 V VDD = 3.3 V VDD = 5.5 V VDD = 1.7 V VDD = 3.3 V VDD = 5.5 V VDD = 3.3 V VDD = 3.3 V 1 1 nA nA VDD = 1.7 V, VIN = VDD VDD = 1.7 V, VIN = 0.1 V 250 250 0.1 0.1 mV mV μA μA VDD = 1.7 V, IOUT = 3 mA VDD = 5.5 V, IOUT = 5 mA VDD = 1.7 V, VOUT = VDD VDD = 1.7 V, VOUT = 5.5 V 13 14 μA μA VDD = 1.7 V VDD = 5.5 V 1 RL = 100 kΩ, VOUT = 2 V swing. VIN =10 mV input overdrive. VIN = 40 mV overdrive. 4 No load. 2 3 Rev. 0 | Page 4 of 16 Data Sheet ADCMP671 VDD = 1.7 V to 5.5 V, −40°C ≤ TA ≤ +85°C, unless otherwise noted. Table 3. Parameter THRESHOLDS 1 Rising Input Threshold Voltage (VTH(R)) Falling Input Threshold Voltage (VTH(F)) Rising Input Threshold Voltage Accuracy Falling Input Threshold Voltage Accuracy Hysteresis = VTH(R) − VTH(F) INPUT CHARACTERISTICS Input Bias Current OPEN-DRAIN OUTPUTS Output Low Voltage 2 Output Leakage Current 3 POWER SUPPLY Supply Current 4 Min 391.2 393.1 393.5 383.3 384.7 384.4 5.4 Typ Max Unit Test Conditions/Comments 407.8 405.9 405.4 400.9 398.4 398.2 ±1.6 ±1.75 12.6 mV mV mV mV mV mV % % mV VDD = 1.7 V VDD = 3.3 V VDD = 5.5 V VDD = 1.7 V VDD = 3.3 V VDD = 5.5 V VDD = 3.3 V VDD = 3.3 V 1 1 nA nA VDD = 1.7 V, VIN = VDD VDD = 1.7 V, VIN = 0.1 V 250 250 0.1 0.1 mV mV μA μA VDD = 1.7 V, IOUT = 3 mA VDD = 5.5 V, IOUT = 5 mA VDD = 1.7 V, VOUT = VDD VDD = 1.7 V, VOUT = 5.5 V 14 15 μA μA VDD = 1.7 V VDD = 5.5 V 1 RL = 100 kΩ, VOUT = 2 V swing. VIN = 10 mV input overdrive. VIN = 40 mV overdrive. 4 No load. 2 3 Rev. 0 | Page 5 of 16 ADCMP671 Data Sheet VDD = 1.7 V to 5.5 V, −40°C ≤ TA ≤ +125°C, unless otherwise noted. Table 4. Parameter THRESHOLDS 1 Rising Input Threshold Voltage (VTH(R)) Falling Input Threshold Voltage (VTH(F)) Rising Input Threshold Voltage Accuracy Falling Input Threshold Voltage Accuracy Hysteresis = VTH(R) − VTH(F) INPUT CHARACTERISTICS Input Bias Current Min Typ 391.2 393.1 393.1 381.1 381.2 381 5.4 OPEN-DRAIN OUTPUTS Output Low Voltage 2 Output Leakage Current 3 POWER SUPPLY Supply Current 4 1 RL = 100 kΩ, VOUT = 2 V swing. VIN = 10 mV input overdrive. VIN = 40 mV overdrive. 4 No load. 2 3 Rev. 0 | Page 6 of 16 Max Unit Test Conditions/Comments 407.8 405.9 405.8 400.9 398.4 398.2 ±1.6 ±2.2 13.5 mV mV mV mV mV mV % % mV VDD = 1.7 V VDD = 3.3 V VDD = 5.5 V VDD = 1.7 V VDD = 3.3 V VDD = 5.5 V VDD = 3.3 V VDD = 3.3 V 2.5 2.5 nA nA VDD = 1.7 V, VIN = VDD VDD = 1.7 V, VIN = 0.1 V 250 250 0.1 0.1 mV mV μA μA VDD = 1.7 V, IOUT = 3 mA VDD = 5.5 V, IOUT = 5 mA VDD = 1.7 V, VOUT = VDD VDD = 1.7 V, VOUT = 5.5 V 16 17 μA μA VDD = 1.7 V VDD = 5.5 V Data Sheet ADCMP671 ABSOLUTE MAXIMUM RATINGS Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Table 5. Parameter VDD INH, INL OV, PWRGD Output Short-Circuit Duration1 Input Current Operating Temperature Range Storage Temperature Range Lead Temperature Soldering (10 sec) Vapor Phase (60 sec) Infrared (15 sec) 1 Rating −0.3 V to +6 V −0.3 V to +6 V −0.3 V to +6 V Indefinite −10 mA −40°C to +125°C −65°C to +150°C THERMAL RESISTANCE θJA is specified for the worst-case conditions, that is, a device soldered in a circuit board for surface-mount packages. 300°C 215°C 220°C Table 6. Thermal Resistance When the output is shorted indefinitely, the use of a heat sink may be required to keep the junction temperature within the absolute maximum ratings. Package Type 6-Lead TSOT ESD CAUTION Rev. 0 | Page 7 of 16 θJA 200 Unit °C/W ADCMP671 Data Sheet PWRGD 1 GND 2 INH 3 ADCMP671 TOP VIEW (Not to Scale) 6 OV 5 VDD 4 INL 10160-003 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS Figure 3. Pin Configuration Table 7. Pin Function Descriptions Pin No. 1 Mnemonic PWRGD 2 3 GND INH 4 INL 5 6 VDD OV Description Open-Drain Active High Power Good Output. It asserts when the input falls within the UV and OV window, for example, INH high and INL low. Ground. Monitors for Supply Undervoltage Fault Through an External Resistor Divider Network. It is internally connected to the noninverting input of a comparator. The other input of the comparator is connected to a 400 mV reference. Monitors for Supply Overvoltage Fault Through an External Resistor Divider Network. It is internally connected to the inverting input of a comparator. The other input of the comparator is connected to a 400 mV reference. Power Supply Pin. Open-Drain Output Active Low Overvoltage Fault Indication Output. It asserts when there is an overvoltage fault, for example, INL high. Rev. 0 | Page 8 of 16 Data Sheet ADCMP671 TYPICAL PERFORMANCE CHARACTERISTICS 50 VDD = 5V TA = 25°C VDD = 5V TA = 25°C 40 PERCENT OF UNITS (%) 40 30 20 FALLING INPUT THRESHOLD VOLTAGE (mV) Figure 4. Distribution of Rising Input Threshold Voltage Figure 7. Distribution of Falling Input Threshold Voltage 402 VDD = 5V TA = 25°C RISING INPUT THRESHOLD VOLTAGE (mV) PERCENT OF UNITS (%) 30 25 20 15 10 5 6.0 6.4 6.8 7.2 7.6 8.0 8.4 8.8 9.2 9.6 10.0 10.4 10.8 HYSTERESIS (mV) 401 401 RISING INPUT THRESHOLD VOLTAGE (mV) FOUR TYPICAL PARTS VDD = 5V 398 –20 0 20 40 60 80 0 20 40 60 80 100 120 Figure 8. Rising Input Threshold Voltage vs. Temperature for Various VDD Voltages 400 396 –40 –20 TEMPERATURE (°C) 100 TEMPERATURE (°C) 120 TA = –40°C 400 TA = +25°C 399 TA = +85°C 398 397 TA = +125°C 396 395 1.7 10160-006 RISING INPUT THRESHOLD VOLTAGE (mV) 402 1 2 3 4 = 1.8V = 2.5V = 3.3V = 5.0V 399 Figure 5. Distribution of Hysteresis 404 VDD VDD VDD VDD 400 398 –40 10160-005 0 388 389 390 391 392 393 394 395 396 397 398 399 400 10160-007 0 10160-004 394 395 396 397 398 399 400 401 402 403 404 405 406 RISING INPUT THRESHOLD VOLTAGE (mV) 35 20 10 10 0 30 10160-008 PERCENT OF UNITS (%) 50 2.2 2.7 3.2 3.7 4.2 4.7 5.2 5.7 SUPPLY VOLTAGE (V) Figure 6. Rising Input Threshold Voltage vs. Temperature for Four Typical Parts Figure 9. Rising Input Threshold Voltage vs. Supply Voltage Rev. 0 | Page 9 of 16 10160-009 60 ADCMP671 11.0 10.5 10.0 9.5 9.0 FOUR TYPICAL PARTS VDD = 5V 8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 10.0 9.5 9.0 = 1.8V = 2.5V = 3.3V = 5.0V 8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 –20 0 20 40 60 80 100 120 TEMPERATURE (°C) 4.0 –40 10160-010 4.5 4.0 –40 VDD VDD VDD VDD 11.0 10.5 HYSTERESIS (mV) HYSTERESIS (mV) 12.0 11.5 1NH1 1NL1 INH2 INL2 –20 0 20 40 60 80 100 120 TEMPERATURE (°C) Figure 10. Hysteresis vs. Temperature for Four Typical Parts 10160-013 12.0 11.5 Data Sheet Figure 13. Hysteresis vs. Temperature for Various VDD Voltages 1 12 TA = +125°C 11 0 THRESHOLD SHIFT (mV) TA = +25°C 9 TA = +85°C 8 7 TA = –40°C 6 TA = –40°C TA = +25°C TA = +85°C TA = +125°C –1 –2 –3 2.2 2.7 3.2 3.7 4.2 4.7 5.2 5.7 SUPPLY VOLTAGE (V) –5 1.5 10160-011 4 1.7 1.9 2.0 2.1 2.2 2.3 2.4 2.5 50 NO LOAD CURRENT 8 SUPPLY CURRENT (µA) 40 TA = +125°C TA = +85°C 7 TA = +25°C 6 TA = –40°C 5 2.2 2.7 30 20 TA = +25°C 10 3.2 3.7 4.2 4.7 5.2 SUPPLY VOLTAGE (V) 10160-012 SUPPLY CURRENT (µA) 1.8 Figure 14. Minimum Supply Voltage 9 4 1.7 1.7 SUPPLY VOLTAGE (V) Figure 11. Hysteresis vs. Supply Voltage 10 1.6 10160-014 –4 5 Figure 12. Quiescent Supply Current vs. Supply Voltage 0 TA = +85°C TA = +125°C TA = –40°C 0 0.5 1.0 SUPPLY VOLTAGE (V) Figure 15. Start-Up Supply Current Rev. 0 | Page 10 of 16 1.5 10160-015 HYSTERESIS (mV) 10 Data Sheet 10 0.01 0.1 1 10 100 OUTPUT SINK CURRENT (mA) TA = 25°C VDD VDD VDD VDD 100 10 1 0.001 0.01 0.1 1 10 100 OUTPUT SINK CURRENT (mA) Figure 16. Supply Current vs. Output Sink Current for TA = −40°C Figure 19. Supply Current vs. Output Sink Current for TA = 25°C 1000 10k = 5.0V = 3.3V = 2.5V = 1.7V 1k 100 10 0.01 0.1 1 10 100 100 TA = +85°C TA = +25°C 10 OUTPUT SINK CURRENT (mA) TA = –40°C 0.1 –0.3 10160-018 1 0.001 –0.2 0 –0.1 INPUT VOLTAGE (V) Figure 17. Supply Current vs. Output Sink Current for TA = 85°C Figure 20. Below Ground Input Bias Current vs. Input Voltage 10 INPUT BIAS CURRENT (nA) 1 TA = +125°C TA = +85°C TA = +25°C TA = –40°C –1 –3 –5 0 0.2 0.4 0.6 0.8 INPUT VOLTAGE (V) 1.0 10160-020 CURRENT IS POSITIVE GOING INTO THE DEVICE VDD = 5V 0V < VIB < 1V Figure 18. Low Level Input Bias Current vs. Input Voltage TA = +125°C 1 TA = +85°C TA = +25°C 0.1 0.01 TA = –40°C CURRENT IS GOING INTO THE DEVICE VDD = 5V VIB > 1V 1 2 3 4 INPUT VOLTAGE (V) Figure 21. High Level Input Bias Current vs. Input Voltage Rev. 0 | Page 11 of 16 5 10160-021 3 –7 CURRENT IS GOING OUT OF THE DEVICE. VDD = 5V –0.3V < VIB < 0V TA = +125°C INPUT BIAS CURRENT (nA) VDD VDD VDD VDD TA = 85°C 1 INPUT BIAS CURRENT (nA) = 5.0V = 3.3V = 2.5V = 1.7V 10160-017 SUPPLY CURRENT (µA) 100 1 0.001 SUPPLY CURRENT (µA) 1000 = 5.0V = 3.3V = 2.5V = 1.7V 10160-019 VDD VDD VDD VDD TA = –40°C 10160-016 SUPPLY CURRENT (µA) 1000 ADCMP671 ADCMP671 1000 100 10 1 0.001 0.01 0.1 1 10 OUTPUT SINK CURRENT (mA) Figure 22. Output Saturation Voltage vs. Output Sink Current for TA = 25°C 10 0.01 0.1 1 10 OUTPUT SINK CURRENT (mA) Figure 25. Output Saturation Voltage vs. Output Sink Current for TA = −40°C 80 TA = 85°C VDD = 5.0V VDD = 3.3V VDD = 2.5V VDD = 1.8V VDD = 5V SHORT-CIRCUIT CURRENT (mA) 10 TA = –40°C TA = +25°C 70 100 60 50 TA = +85°C TA = +125°C 40 30 20 0.1 1 10 OUTPUT SINK CURRENT (mA) 0 OUTPUT LEAKAGE CURRENT (nA) 50 VDD = 3.3V 40 30 VDD = 2.5V 20 VDD = 1.8V 0 2 4 OUTPUT VOLTAGE (V) 10160-026 10 0 VDD = 5V VDD = 5.0V 60 4 Figure 26. Output Short-Circuit Current vs. Output Voltage 10 TA = 25°C 2 OUTPUT VOLTAGE (V) Figure 23. Output Saturation Voltage vs. Output Sink Current for TA = 85°C 70 0 Figure 24. Output Short-Circuit Current vs. Output Voltage TA = +125°C 1 TA = +85°C TA = +25°C 0.1 TA = –40°C 0.01 0.001 0 1 2 3 4 OUTPUT VOLTAGE (V) Figure 27. Output Leakage Current vs. Output Voltage Rev. 0 | Page 12 of 16 5 10160-027 0.01 10160-025 10 1 0.001 SHORT-CIRCUIT CURRENT (mA) 100 1 0.001 10160-024 OUTPUT SATURATION VOLTAGE (mV) 1000 TA = –40°C VDD = 5.0V VDD = 3.3V VDD = 2.5V VDD = 1.8V 10160-023 OUTPUT SATURATION VOLTAGE (mV) TA = 25°C VDD = 5.0V VDD = 3.3V VDD = 2.5V VDD = 1.8V 10160-022 OUTPUT SATURATION VOLTAGE (mV) 1000 Data Sheet Data Sheet 70 ADCMP671 5 TA = 25°C INH LH INL LH INH HL INL HL OUTPUTS BEING PULLED UP TO VDD WITH 10kΩ INH = LOW INL = LOW 4 50 40 VOUT (V) PROPAGATION DELAY (µs) 60 30 3 2 20 1 PWRGD 10 0 20 40 60 80 100 INPUT OVERDRIVE (mV) 0 10160-028 0 0 1 2 3 4 5 VDD (V) Figure 28. Propagation Delay vs. Input Overdrive 10160-031 OV Figure 31. Output Voltage vs. Supply Voltage with Both INH and INL Low 5 INL VTH(R) INH VTH(R) INL VTH(F) OUTPUTS BEING PULLED UP TO VDD WITH 10kΩ INH = HIGH INL = LOW 4 VOUT (V) VIN INH VTH(F) 1 PWRGD 3 3 2 OV 1 CH4 5.0V OV 0 M40.0µs 0 1 2 3 4 5 VDD (V) Figure 29. Propagation Delay Figure 32. Output Voltage vs. Supply Voltage with INH High and INL Low 5 VDD = 5V CL = 20pF TA = 25°C OUTPUTS BEING PULLED UP TO VDD WITH 10kΩ INH = HIGH INL = HIGH 4 10 VOUT (V) RISE 1 3 2 0.1 1 FALL 1 10 100 1000 OUTPUT PULL-UP RESISTOR (kΩ) Figure 30. Rise and Fall Times vs. Output Pull-Up Resistor 0 0 1 2 3 VDD (V) 4 5 10160-033 0.01 0.1 PWRGD OV 10160-030 RISE AND FALL TIMES (µs) 100 10160-032 CH3 5.0V PWRGD 10160-029 R_PULLUP = 10kΩ V_PULLUP = 5V 4 Figure 33. Output Voltage vs. Supply Voltage with Both INH and INL High Rev. 0 | Page 13 of 16 ADCMP671 Data Sheet APPLICATIONS INFORMATION The ADCMP671 is a UV and OV monitor with a built-in 400 mV reference that operates from 1.7 V to 5.5 V. The comparator is 0.275% accurate with a built-in hysteresis of 9.2 mV. The outputs are open-drain, capable of sinking 40 mA. 12V 5V VDD ADCMP671 RX PWRGD INH UV There are two comparators inside the ADCMP671. The comparator with its noninverting input connected to the INH pin (and its inverting input connected internally to the 400 mV reference) is for undervoltage detection, and the comparator with its inverting input available through the INL pin (and its noninverting input connected internally to the 400 mV reference) is for overvoltage detection. The rising input threshold voltage of the comparators is designed to be equal to that of the reference. POWER SUPPLY The ADCMP671 is designed to operate from 1.7 V to 5.5 V. A 0.1 μF decoupling capacitor is recommended between VDD and GND. INL To minimize the number of external components use three resistor dividers to program the UV and OV thresholds. HYSTERESIS To prevent oscillations at the output caused by noise or slowly moving signals passing the switching threshold, each comparator has a built-in hysteresis of approximately 8.9 mV. VOLTAGE MONITORING SCHEME When monitoring a supply rail, the desired nominal operating voltage for monitoring is denoted by VM, IM is the nominal current through the resistor divider, VOV is the overvoltage trip point, and VUV is the undervoltage trip point. Figure 34 illustrates the voltage monitoring input connection. Three external resistors, RX, RY, and RZ, divide the positive voltage for monitoring (VM) into the high-side voltage (VH) and lowside voltage (VL). The high-side voltage is connected to the INH pin, and the low-side voltage is connected to the INL pin. OV RZ GND Figure 34. Undervoltage/Overvoltage Monitoring Configuration To trigger an overvoltage condition, the low-side voltage (in this case, VL) must exceed the 0.4 V threshold on the INL pin. The low-side voltage, VL, is given by the following equation: ⎛ RZ VL = VOV ⎜⎜ ⎝ RX + RY + RZ INPUTS The comparator inputs are limited to the maximum VDD voltage range. The voltage on these inputs can be more than VDD but never more than the maximum allowed VDD voltage. When adding a resistor string to the input, choose resistor values carefully because the input bias current is in parallel with the bottom resistor of the string. Therefore, choose the bottom resistor first to control the error introduced by the bias current. OV 400mV RY 10160-034 COMPARATORS AND INTERNAL REFERENCE ⎞ ⎟ = 0.4 V ⎟ ⎠ Also, R X + RY + RZ = VM IM Therefore, RZ, which sets the desired trip point for the overvoltage monitor, is calculated using the following equation: RZ = (0.4)(VM ) (VOV )(I M ) To trigger the undervoltage condition, the high-side voltage, VH, must fall below the 0.4 V threshold on the INH pin. The highside voltage, VH, is given by the following equation: ⎛ RY + RZ VH = VUV ⎜⎜ ⎝ R X + RY + RZ ⎞ ⎟ = 0.4 V ⎟ ⎠ Because RZ is already known, RY can be expressed as follows: RY = (0.4)(VM ) −R (VUV )(I M ) Z When RY and RZ are known, RX is calculated using the following equation: RX = (VM ) − R − R (I M ) Z Y If VM, IM, VOV, or VUV changes each step must be recalculated. Rev. 0 | Page 14 of 16 Data Sheet ADCMP671 PWRGD 2.5V The PWRGD output is used to indicate supply power good for the rail being monitored. It asserts if the monitored voltage falls within the UV and OV threshold window. The OV output acts as a dedicated overvoltage indication output, allows the board manager to take decisive action to protect the system from overvoltage faults. Both outputs are open-drain and can be pulled up to voltages above VDD. These outputs are capable of sinking current up to 40 mA. In the multisupply monitoring application, multiple ADCMP671 can be used with their OV pin tied together to generate a single overvoltage fault alert signal, as shown in Figure 35. During power up and power down, the power management processor of the board can manage supply sequencing based on PWRGD signals. In the event of supply overvoltage fault, the processor can react quickly to the provide necessary circuit protection because of its dedicated OV alert. The processor is also able to identify the faulty supply from combining the information on the PWRGD pins. This allows the processor to use the N + 1 input pins to individually monitor N channels of supplies. Rev. 0 | Page 15 of 16 1.8V ADCMP671 OV PWRGD ADCMP671 OV PWRGD 1.0V 2.5V GOOD 1.8V GOOD 1.0V GOOD 0.9V GOOD ADCMP671 OV FAULT BOARD MANAGER OV PWRGD 0.9V ADCMP671 OV Figure 35. N Rails Monitoring with N + 1 Processor I/O 10160-035 OUTPUTS ADCMP671 Data Sheet OUTLINE DIMENSIONS 2.90 BSC 6 5 4 2.80 BSC 1.60 BSC 1 3 2 PIN 1 INDICATOR 0.95 BSC 1.90 BSC *1.00 MAX 0.10 MAX SEATING PLANE 0.50 0.30 0.20 0.08 8° 4° 0° 0.60 0.45 0.30 *COMPLIANT TO JEDEC STANDARDS MO-193-AA WITH THE EXCEPTION OF PACKAGE HEIGHT AND THICKNESS. 102808-A *0.90 0.87 0.84 Figure 36. 6-Lead Thin Small Outline Transistor Package [TSOT] (UJ-6) Dimensions shown in millimeters ORDERING GUIDE Model 1 ADCMP671-1YUJZ-RL7 1 Temperature Range −40°C to +125°C Package Description 6-Lead Thin Small Outline Transistor Package [TSOT] Z = RoHS Compliant Part. ©2011 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D10160-0-11/11(0) Rev. 0 | Page 16 of 16 Package Option UJ-6 Branding LLS