ADM8710L2ARJZ-RL7

FEATURES Accurate monitoring of up to four power supply voltages 2 factory-set threshold options for monitoring 1.8 V and 3.3 V Adjustable input threshold voltage 0.62 V (±1.5% accuracy) 50 ms typical reset timeout Open-drain RESET output (10 µA internal pull-up) Reset output stage: active low, valid to IN1 = 1 V or IN2 = 1 V Power supply glitch immunity Specified from −40°C to +85°C 6-lead SOT-23 package APPLICATIONS Telecommunications Microprocessor systems Desktop and notebook computers Data storage equipment Servers/workstations FUNCTIONAL BLOCK DIAGRAM IN1 ADM8710 IN2 IN2 RESET RESET TIMEOUT IN3 UVLO IN4 10647-001 Data Sheet Low Voltage, High Accuracy, Quad Voltage Microprocessor Supervisory Circuit ADM8710 0.62VREF Figure 1. GENERAL DESCRIPTION The ADM8710 is a low voltage, high accuracy supervisory circuit. The device monitors up to four system supply voltages. The ADM8710 incorporates two internally pretrimmed undervoltage threshold options for monitoring 1.8 V and 3.3 V supply voltages. It also offers two adjustable inputs with 0.62 V internal reference, allowing users to program the reset threshold through external resistor dividers. The combination of pretrimmed and adjustable inputs gives the ADM8710 the advantage of being both space saving and flexible. If a monitored power supply voltage falls below the minimum voltage threshold, a single active low output asserts, triggering a system reset. The output is open drain with a weak internal pull-up to the monitored IN2 supply of typically 10 µA. When all voltages rise above the selected threshold level, the RESET signal remains low for the reset timeout period. The ADM8710 output remains valid as long as IN1 or IN2 exceeds 1 V. Unused monitored inputs should not be allowed to float or to be grounded. Instead, connect them to a supply voltage greater than their specified threshold voltages. The ADM8710 is available in a 6-lead SOT-23 package. The device operates over the extended temperature range of −40°C to +85°C. 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 ©2012 Analog Devices, Inc. All rights reserved. ADM8710 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Theory of Operation .........................................................................8 Applications ....................................................................................... 1 Input Configuration ......................................................................8 Functional Block Diagram .............................................................. 1 RESET Output Configuration .....................................................8 General Description ......................................................................... 1 Addition of Manual Reset ............................................................8 Revision History ............................................................................... 2 Tolerance and Accuracy ...............................................................9 Specifications..................................................................................... 3 Model Options ................................................................................ 10 Absolute Maximum Ratings ............................................................ 4 Outline Dimensions ....................................................................... 11 ESD Caution .................................................................................. 4 Ordering Guide .......................................................................... 11 Pin Configuration and Function Descriptions ............................. 5 Typical Performance Characteristics ............................................. 6 REVISION HISTORY 8/12—Revision 0: Initial Version Rev. 0 | Page 2 of 12 Data Sheet ADM8710 SPECIFICATIONS VIN2 = 1 V to 5.5 V, TA = −40°C to +85°C, unless otherwise noted. Typical values are VIN2 = 3.0 V to 3.3 V, TA = 25°C. Table 1. Parameter OPERATING VOLTAGE RANGE VIN2 1 Min Typ Max Units Test Conditions/Comments 5.5 5.5 V V TA = 0°C to 85°C TA = −40°C to +85°C 55 115 µA 25 40 0.4 0.2 µA µA µA IN2 = nominal input voltage (3.3 V supplies); the supply splits into 25 µA for the resistor divider and 30 µA for other circuits IN3 = nominal input voltage (1.8 V supplies) VIN1 = 0 V to 0.85 V VIN4 = 0 V to 0.85 V 3.010 1.705 0.611 3.07 1.73 0.62 3.130 1.760 0.629 V V V INX decreasing; 3.3 V (−5% supply tolerance) INX decreasing; 1.8 V (−2% supply tolerance) INX decreasing %VTH ppm/°C µs ms V V V V µA INX increasing relative to INX decreasing 35 0.3 60 30 50 1.0 1.2 INPUT CURRENT INx Input Current THRESHOLD VOLTAGE Threshold Voltage (VTH) Adjustable Input Threshold Voltage (VTH) RESET Reset Threshold Hysteresis (VHYST) Reset Threshold Temperature Coefficient (TCVTH) INX to Reset Delay (tRP) Reset Timeout Period (tRP) RESET Output Low (VOL) RESET Output High (VOH) RESET Output High Source Current (IOH) 1 70 0.3 0.4 0.3 0.8 × VIN2 10 The RESET output is guaranteed to be in the correct state for IN1 or IN2 down to 1 V. Rev. 0 | Page 3 of 12 VIN falling at 10 mV/µs from VTH to VTH − 50 mV VIN2 = 5 V, ISINK = 2 mA VIN2 = 2.5 V, ISINK = 1.2 mA VIN2 = 1.0 , ISINK = 20 µA, TA = 0°C to +85°C VIN2 ≥ 2.0 V, ISOURCE = 4 µA, RESET deasserted VIN2 ≥ 2.0 V, RESET deasserted ADM8710 Data Sheet ABSOLUTE MAXIMUM RATINGS Table 3. Thermal Resistance Table 2. Parameter INX, RESET to GND Continuous RESET Current Storage Temperature Range Operating Temperature Range Lead Temperature (10 sec) Junction Temperature Package Type 6-lead SOT-23 Rating −0.3 V to +6 V 20 mA −65°C to +125°C −40°C to +85°C 300°C 135°C ESD CAUTION 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. Rev. 0 | Page 4 of 12 θJA 169.5 Unit °C/W Data Sheet ADM8710 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS IN1 1 6 RESET 5 GND 4 IN4 IN2 2 IN3 3 TOP VIEW (Not to Scale) 10647-002 ADM8710 Figure 2. Pin Configuration Table 4. Pin Function Descriptions Pin No. 1 2 3 4 5 6 Mnemonic IN1 IN2 IN3 IN4 GND RESET Description Input Voltage 1. Input Voltage 2. Input Voltage 3. Input Voltage 4. Ground. Active Low RESET Output. RESET goes low when an input drops to less than the specified threshold. When all inputs rise higher than the threshold voltage, RESET remains low for the reset timeout period before going high. RESET is open drain with a weak internal pull-up to IN2. Rev. 0 | Page 5 of 12 ADM8710 Data Sheet TYPICAL PERFORMANCE CHARACTERISTICS VIN2 = 3.0 V, TA = 25°C, unless otherwise noted. 100 58 IN2 INPUT CURRENT (µA) 56 54 52 50 48 46 44 10647-003 VIN2 = 3.3V 42 VIN2 = 3V 40 –40 –15 10 35 90 80 70 60 50 40 30 RESET ASSERTED ABOVE THIS LINE 20 10 0 85 60 10647-006 MAXIMUM INX TRANSIENT DURATION (µs) 60 0 100 TEMPERATURE (ºC) 200 300 400 500 600 700 800 900 1000 RESET THRESHOLD OVERDRIVE (mV) Figure 3. IN2 Input Current vs. Temperature Figure 6. Maximum INx Transient Duration vs. Reset Threshold Overdrive 120 100 90 80 RESET DELAY (µs) 80 60 40 70 60 50 40 30 10647-004 0 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 10647-007 20 20 10 0 5.5 0 IN2 VOLTAGE (V) 58.5 RESET TIMEOUT DELAY (ms) 0 –0.05 –0.10 –0.15 –0.20 –0.25 VTH = 1.8V VIN2 = 3.3V 10 35 400 500 600 700 800 900 1000 60 58.0 57.5 57.0 56.5 56.0 55.5 10647-005 NORMALIZED THERSHOLD ERROR (%) 59.0 –15 300 Figure 7. RESET Delay vs. Reset Threshold Overdrive (INx Decreasing) 0.05 –0.35 –40 200 RESET THRESHOLD OVERDRIVE (mV) Figure 4. IN2 Input Current vs. IN2 Voltage –0.30 100 55.0 –40 85 TEMPERATURE (ºC) –15 10 35 60 TEMPERATURE (°C) Figure 8. Normalized Reset Timeout Delay vs. Temperature Figure 5. Normalized Threshold Error vs. Temperature Rev. 0 | Page 6 of 12 85 10647-008 IN2 INPUT CURRENT (µA) 100 Data Sheet ADM8710 INx INx 1 1 RESET RESET CH3 2.0V CH4 2.0V M10.0µs 125MS/s 8.0ns/pt A CH3 10647-010 2 10647-009 2 CH3 2.0V CH4 2.0V 960mV M10.0ms 125kS/s 8.0µs/pt A CH3 Figure 10. Timeout Delay (10 ms/DIV) Figure 9. RESET Pull-Up and Pull-Down Response (10 µs/DIV) Rev. 0 | Page 7 of 12 960mV ADM8710 Data Sheet THEORY OF OPERATION The ADM8710 is a compact, low power supervisory circuit capable of monitoring up to four voltages in a multisupply application. The device includes two factory-set voltage threshold options for monitoring 1.8 V and 3.3 V supplies. It also provides two adjustable thresholds for monitoring voltages down to 0.62 V. The ADM8710 is powered by IN2, which is a monitored voltage, and therefore monitors up to four voltages. If a monitored voltage drops below its associated threshold, the active low reset output asserts low and remains low while either IN1 or IN2 remains above 1.0 V. ADM8710 IN1 1.8V 0.9V IN2 RESET IN3 MICROPROCESSOR IN4 10647-011 GND RESET OUTPUT CONFIGURATION The RESET output asserts low when a monitored INx voltage drops below its voltage threshold. When all voltages rise above the selected threshold level, the RESET signal remains low for the reset timeout period. The RESET output is open drain with a weak internal pull-up to the monitored IN2, typically 10 µA. Many applications that interface with other logic devices do not require an external pull-up resistor. However, if an external pull-up resistor is required and it is connected to a voltage ranging from 0 V to 5.5 V, it overdrives the internal pull-up. Reverse current flow from the external pull-up voltage to IN2 is prevented by the internal circuitry. 1.2V 3.3V Do not allow unused monitor inputs to float or to be grounded. Connect these inputs to a supply voltage greater than their specified threshold voltages. In the case of unused INx adjustable inputs, limit the bias current by connecting a 1 MΩ series resistor between the unused input and IN2. 5V IN2 = 3.3V Figure 11. Typical Applications Circuit INPUT CONFIGURATION ADM8710 The ADM8710 provides numerous monitor choices with adjustable reset thresholds. Typically, the threshold voltage at each adjustable INx input is 0.62 V. To monitor a voltage greater than 0.62 V, connect a resistor divider network to the circuit as depicted in Figure 12, where VCC 100kΩ RESET 10647-013 RESET Figure 13. Interface with a Different Logic Supply Voltage R1 + R2  VINTH = 0.62 V    R2  ADDITION OF MANUAL RESET Use the circuit shown in Figure 14 to add manual reset to any of the ADM8710 adjustable inputs. When the switch is closed, the analog input shorts to ground and a RESET output commences. The switch must remain open for a minimum of 35 ms for the RESET output to deassert. VINTH R1 ADM8710 Figure 12. Setting the Adjustable Monitor VIN4 The internal comparators each typically have a hysteresis of 0.3% with respect to the reset threshold. This built-in hysteresis improves the immunity of the device to ambient noise without noticeably reducing the threshold accuracy. The ADM8710 is unaffected by short input transients. The ADM8710 is powered from the monitored IN2. Monitored inputs are resistant to short power supply glitches. Figure 6 depicts the ADM8710 glitch immunity data. To increase noise immunity in noisy applications, place a 0.1 µF capacitor between the IN2 input and ground. Adding capacitance to IN1, IN3, and IN4 also improves noise immunity. Rev. 0 | Page 8 of 12 IN1 IN2 R1 IN3 RESET IN4 GND R2 10647-014 VREF = 0.62V 10647-012 R2 Figure 14. Addition of Manual Reset (IN4 is an Adjustable Input) Data Sheet ADM8710 TOLERANCE AND ACCURACY The primary function of the voltage supervisor is to keep the processor in a reset state whenever the processor supply voltage is below the specification limit. It needs to be able to differentiate the voltage out-of-processor limit from supply variations caused by voltage converter output tolerance. This means that the supervisor rest threshold should fit inside the narrow band between processor input tolerance and supply tolerance. The ADM8710 offers up to ±2% accuracy on factory trimmed monitoring thresholds and ±1.5% accuracy on adjustable thresholds over the entire operating temperature range. VOLTAGE SUPPLY VOLTAGE SUPPLY TOLERANCE THRESHOLD TOLERANCE RESET tRP TIME 10647-015 PROCESSOR INPUT TOLERANCE Figure 15. Tighter Threshold Tolerance on Voltage Supervisor Reduces Accuracy Requirement on Monitored Supply Rev. 0 | Page 9 of 12 ADM8710 Data Sheet MODEL OPTIONS Table 5. Reset Voltage Threshold Options IN1 Reset Threshold Code 1 L 1 Nominal Input Voltage (V) Adjustable IN2 Supply Tolerance (%) Not applicable Nominal Input Voltage (V) 3.3 IN3 Supply Tolerance (%) −5 Nominal Input Voltage (V) 1.8 IN4 Supply Tolerance (%) −2 Nominal Input Voltage (V) Adjustable Supply Tolerance (%) Not applicable Adjustable voltage based on 0.62 V internal threshold. The external threshold voltage can be set using an external resistor divider. Table 6. Reset Timeout Options Reset Timeout Period Code 1 ADM8710x2 TA = −40°C to +85°C Typ Max 50 70 x = do not care. ADM8710L2ARJZ-RL7 PACKING MATERIAL RL7 = 7” TAPE AND REEL (3000 PIECE QUANTITY) RESET THRESHOLD CODE RESET TIMEOUT PERIOD CODE 2 = 50ms TYPICAL Z = LEAD-FREE TEMPERATURE RANGE A: –40°C TO +85°C PACKAGE DESIGNATOR RJ = SOT-23 Figure 16. ADM8710 Ordering Code Structure Rev. 0 | Page 10 of 12 10647-016 1 Min 35 Unit ms Data Sheet ADM8710 OUTLINE DIMENSIONS 3.00 2.90 2.80 1.70 1.60 1.50 6 5 4 1 2 3 3.00 2.80 2.60 PIN 1 INDICATOR 0.95 BSC 1.90 BSC 1.45 MAX 0.95 MIN 0.15 MAX 0.05 MIN 0.50 MAX 0.30 MIN 0.20 MAX 0.08 MIN SEATING PLANE 10° 4° 0° 0.60 BSC COMPLIANT TO JEDEC STANDARDS MO-178-AB 0.55 0.45 0.35 12-16-2008-A 1.30 1.15 0.90 Figure 17. 6-Lead Small Outline Transistor Package [SOT-23] (RJ-6) Dimensions shown in millimeters ORDERING GUIDE Model 1, 2 ADM8710L2ARJZ-RL7 1 2 Monitored Input Voltage (V) IN1 IN2 IN3 IN4 Adj. 3.07 1.73 Adj. Minimum Reset Timeout (ms) 35 Temperature Range −40°C to +85°C Ordering Quantity 3,000 Package Description 6-Lead SOT-23 Z = RoHS Compliant Part. Adjustable voltage based on 0.62 V internal threshold. The external threshold voltage can be set using an external resistor divider. Rev. 0 | Page 11 of 12 Package Option RJ-6 Branding LN3 ADM8710 Data Sheet NOTES ©2012 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D10647-0-8/12(0) Rev. 0 | Page 12 of 12