ADM708R/ADM708S/ADM708T Precision supply voltage monitor 2.63 (AD

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ADM708R/ADM708S/ADM708T Precision supply voltage monitor 2.63 (AD

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Voltage Monitoring Microprocessor Supervisory Circuits
ADM708R/ADM708S/ADM708T
Precision supply voltage monitor 2.63 (ADM706P, ADM706R, ADM708R) 2.93 (ADM706S, ADM708S) 3.08 (ADM706T, ADM708T) quiescent current reset pulse width Debounced manual reset input (MR) Independent watchdog timer timeout (ADM706x) Reset Output Active high (ADM706P) Active (ADM706R/ADM706S/ADM706T) Both active high active (ADM708R/ADM708S/ADM708T) Voltage monitor power-fail battery warning Guaranteed RESET valid with Superior upgrade MAX706P/R/S/T, MAX708R/S/T
WATCHDOG INPUT (WDI)
FUNCTIONAL BLOCK DIAGRAMS
WATCHDOG TRANSITION DETECTOR VREF* POWER-FAIL INPUT (PFI) 1.25V WATCHDOG TIMER WATCHDOG OUTPUT (WDO)
RESET WATCHDOG TIMEBASE
RESET GENERATOR
RESET, RESET)
ADM706P/ADM706R/ ADM706S/ADM706T
POWER-FAIL OUTPUT (PFO)
06435-001
VOLTAGE REFERENCE 2.63V (P/R), 2.93V (S), 3.08V
Figure ADM706P/ADM706R/ADM706S/ADM706T
VREF POWER-FAIL INPUT (PFI) 1.25V VOLTAGE REFERENCE 2.63V (R), 2.93V (S), 3.08V RESET GENERATOR RESET RESET
APPLICATIONS
Microprocessor systems Computers Controllers Intelligent instruments Critical microprocessor monitoring Automotive systems Battery-operated systems Portable instruments
ADM708R/ADM708S/ ADM708T
06435-002
POWER-FAIL OUTPUT (PFO)
Figure ADM708R/ADM708S/ADM708T
GENERAL DESCRIPTION
ADM706P/ADM706R/ADM706S/ADM706T ADM708R/ADM708S/ADM708T microprocessor supervisory circuits suitable monitoring either power supplies. ADM706P/ADM706R/ADM706S/ADM706T provide following functions: Power-supply monitoring circuitry that generates reset output during power-up, power-down, brownout conditions. reset output remains operational with Independent watchdog monitoring circuitry that activated watchdog input been toggled within sec. 1.25 threshold detector power-fail warning, battery detection, monitor additional power supply. active debounced input. ADM706R, ADM706S, ADM706T identical except reset threshold monitor levels, which 2.63 2.93 3.08 respectively. ADM706P identical ADM706R that reset threshold 2.63 differs only that active high reset output. ADM708R/ADM708S/ADM708T provide same functionality ADM706R/ADM706S/ADM706T only differ that: watchdog timer function available. active high reset output (RESET) addition active (RESET) output available. parts available narrow 8-lead PDIP 8-lead SOIC packages.
Rev.
Information furnished Analog Devices believed accurate reliable. However, responsibility assumed Analog Devices use, infringements patents other rights third parties that result from use. Specifications subject change without notice. license granted implication otherwise under patent patent rights Analog Devices. Trademarks registered trademarks property their respective owners.
Technology Way, P.O. 9106, Norwood, 02062-9106, U.S.A. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 ©2007 Analog Devices, Inc. rights reserved.
ADM708R/ADM708S/ADM708T
TABLE CONTENTS
Features Applications. Functional Block DiagramS General Description Revision History Specifications. Absolute Maximum Ratings. Caution. Configuration Function Descriptions. Typical Performance Characteristics Circuit Information Power-Fail Reset Manual Reset.9 Watchdog Timer (ADM706x) Power-Fail Comparator Adding Hysteresis Power-Fail Comparator Valid RESET Below Applications Information Monitoring Additional Supply Levels. Microprocessors with Bidirectional RESET Outline Dimensions Ordering Guide
REVISION HISTORY
2/07-Rev. Rev. Updated Format.Universal Changes Table Updated Outline Dimensions Changes Ordering Guide
Rev. Page
ADM708R/ADM708S/ADM708T
SPECIFICATIONS
2.70 (ADM706P/ADM70xR), 3.00 (ADM70xS), 3.15 (ADM70xT), TMIN TMAX unless otherwise noted. Table
Parameter POWER SUPPLY Operating Voltage Range Supply Current LOGIC OUTPUT Reset Threshold (VRST) 2.55 2.85 3.00 2.63 2.93 3.08 2.70 3.00 3.15 Unit Test Conditions/Comments
ADM706P/ADM70xR ADM70xS ADM70xT ADM706P/ADM70xR, ADM70xS/T,
Reset Threshold Hysteresis RESET PULSE WIDTH
RESET OUTPUT VOLTAGE (ADM70xR/ADM70xS/ADM70xT) RESET OUTPUT VOLTAGE (ADM706P) RESET OUTPUT VOLTAGE (ADM708x) WATCHDOG INPUT(ADM706x) Watchdog Timeout Period
1.00 1.60 2.25
VRST (max) ISOURCE VRST (max) ISINK ISOURCE ISINK ISINK VRST (max) ISOURCE VRST (max) ISINK ISOURCE ISINK VRST (max) ISOURCE VRST (max) ISINK ISOURCE ISINK ADM706P/ADM706R: ADM706S/ADM706T: VRST (max) VRST (max) VRST (max) VRST (max) ISOURCE ISOURCE VRST (max) ISINK ISINK
Pulse Width Input Threshold Input Current OUTPUT VOLTAGE
-1.0 +0.02 +1.0
Rev. Page
ADM708R/ADM708S/ADM708T
Parameter MANUAL RESET INPUT Pull-Up Current Pulse Width INPUT THRESHOLD RESET OUTPUT DELAY POWER-FAIL INPUT Input Threshold Input Current OUTPUT VOLTAGE Unit VRST (max) ISOURCE VRST (max) ISINK ISOURCE ISINK Test Conditions/Comments VRST (max) VRST (max) VRST (max) VRST (max) VRST (max) ADM70xP/ADM70xR, ADM70xS/ADM70xT, falling
1.25 +0.01
Rev. Page
ADM708R/ADM708S/ADM708T
ABSOLUTE MAXIMUM RATINGS
25°C unless otherwise noted. Table
Parameter Other Inputs Input Current Digital Output Current Power Dissipation, (PDIP) Thermal Impedance Power Dissipation, (SOIC) Thermal Impedance Operating Temperature Range Industrial (Version Lead Temperature (Soldering, sec) Vapor Phase sec) Infrared sec) Storage Temperature Range Rating Rating -0.3 -0.3 135°C/W 110°C/W -40°C +85°C 300°C 215°C 220°C -65°C +150°C
Stresses above those listed under Absolute Maximum Ratings cause permanent damage device. This stress rating only; functional operation device these other conditions above those indicated operational section this specification implied. Exposure absolute maximum rating conditions extended periods affect device reliability.
CAUTION
Rev. Page
ADM708R/ADM708S/ADM708T
CONFIGURATION FUNCTION DESCRIPTIONS
RESET
06435-003
ADM706P
06435-004
CONNECT
Figure ADM706P
Figure ADM706R/ADM706S/ADM706T
Figure ADM708R/ADM708S/ADM708T
Table Function Descriptions
ADM706P/ ADM706R/ ADM706S/ ADM706T ADM708R/ ADM708S/ ADM708T Description Manual Reset Input. When taken below RESET generated. driven from TTL, CMOS logic from manual reset switch internally debounced. internal pull-up current holds input high when floating. Power Supply Input. Ground reference signals Power-Fail Input. noninverting input power-fail comparator. When less than 1.25 goes low. unused, should connected GND. Power-Fail Output. output from power-fail comparator. goes when less than 1.25 Watchdog Input. 3-level input. remains either high longer than watchdog timeout period, watchdog output goes low. timer resets with each transition input. Either high-to-low low-to-high transition clears counter. internal timer also cleared whenever reset asserted. watchdog timer disabled when left floating connected three-state buffer. Connect. Logic Output. RESET goes when triggered. triggered either being below reset threshold signal input. RESET remains whenever below reset threshold. remains after goes above reset threshold goes from high. watchdog timeout does trigger RESET unless connected Logic Output. RESET active high output suitable systems that active high RESET logic. inverse RESET. Logic Output/Watchdog Output. goes internal watchdog timer times result inactivity input. remains until watchdog timer cleared. also goes during line conditions. Whenever below reset threshold, remains low. soon goes above reset threshold, goes high immediately.
Mnemonic
RESET
(ADM706R/ ADM706S/ ADM706T Only) (ADM706P Only)
RESET
Rev. Page
06435-005
VIEW (Not Scale)
ADM706R/ ADM706S/ ADM706T
RESET
VIEW (Not Scale)
VIEW (Not Scale)
ADM708R/ ADM708S/ ADM708T
RESET RESET
ADM708R/ADM708S/ADM708T
TYPICAL PERFORMANCE CHARACTERISTICS
25°C 1.3V 1.2V
RESET
06345-013
06345-016
400ms/DIV
500ns/DIV
Figure ADM70xR/ADM70xS/ADM70xT RESET Output Voltage Supply Voltage
Figure Deassertion Response Time
25°C
RESET RESET
06345-014
RESET
06345-017
400ms/DIV
100ns/DIV
Figure RESET Output Voltage Supply Voltage
Figure RESET, RESET Assertion
25°C 1.3V 1.2V RESET
25°C
RESET
06345-015
500ns/DIV
100ns/DIV
Figure Assertion Response Time
Figure RESET, RESET Deassertion
Rev. Page
06345-018
ADM708R/ADM708S/ADM708T
25°C
RESET
06345-019
2µs/DIV
Figure ADM70xR/ADM70xS/ADM70xT RESET Response Time
Rev. Page
ADM708R/ADM708S/ADM708T
CIRCUIT INFORMATION
WATCHDOG INPUT (WDI) WATCHDOG TRANSITION DETECTOR VREF* POWER-FAIL INPUT (PFI) 1.25V WATCHDOG TIMER
MANUAL RESET
WATCHDOG OUTPUT (WDO)
RESET WATCHDOG TIMEBASE
RESET GENERATOR
RESET, RESET)
input allows other reset sources, such manual reset switch, generate processor reset. input effectively debounced timeout period (200 typical). input TTL-/CMOS-compatible; also driven logic reset output. unused, input tied high left floating.
ADM706P/ADM706R/ ADM706S/ADM706T
POWER-FAIL OUTPUT (PFO)
06435-006
RESET
VOLTAGE REFERENCE 2.63V (P/R), 2.93V (S), 3.08V
Figure ADM706 Functional Block Diagram
VREF POWER-FAIL INPUT (PFI) 1.25V VOLTAGE REFERENCE 2.63V (R), 2.93V (S), 3.08V RESET GENERATOR RESET RESET
EXTERNALLY DRIVEN
NOTES RESET COMPLEMENT RESET
06435-008
Figure RESET, Timing
ADM708R/ADM708S/ ADM708T
06435-007
POWER-FAIL OUTPUT (PFO)
WATCHDOG TIMER (ADM706x)
watchdog timer circuit used monitor activity microprocessor check that stalled indefinite loop. output line processor used toggle watchdog input (WDI) line. this line toggled within timeout period (1.6 sec), watchdog output (WDO) driven low. output connected nonmaskable interrupt (NMI) processor. Therefore, watchdog timer times out, interrupt generated. interrupt service routine should then used rectify problem. watchdog timer cleared either high-to-low low-to-high transition WDI. Pulses narrow detected. timer also cleared RESET/RESET going active. Therefore, watchdog timeout period begins after reset goes inactive. When falls below reset threshold, forced whether watchdog timer timed out. Normally, this generates interrupt, overridden RESET/RESET going active.
Figure ADM708 Functional Block Diagram
POWER-FAIL RESET
reset output provides reset (RESET RESET) output signal microprocessor whenever input below reset threshold. actual reset threshold voltage dependent whether suffix device used. internal timer holds reset output active after voltage rises above threshold. This intended power-on reset signal microprocessor. allows time both power supply microprocessor stabilize after power-up. power supply brownout interruption occurs, reset line similarly activated remains active after supply recovers. another interruption occurs during active reset period, reset timeout period continues additional reset output guaranteed remain valid with This ensures that microprocessor held stable shutdown condition power supply starts ADM706P provides active high RESET signal; ADM706R/ADM706S/ADM706T provide active RESET signal; ADM708R/ADM706S/ADM706T provide both RESET RESET.
Rev. Page
ADM708R/ADM708S/ADM708T
watchdog monitor deactivated floating watchdog input (WDI). output used line output because only goes when falls below reset threshold.
INPUT POWER
ADM663A
3.3V
1.25V MICROPROCESSOR
ADM706P/ADM706R/ ADM706S/ADM706T/ ADM708R/ADM708S/ ADM708T
06435-009
RESET
RESET EXTERNALLY TRIGGERED
3.3V
Figure Watchdog Timing
06435-011
POWER-FAIL COMPARATOR
power-fail comparator independent comparator that used monitor input power supply. comparator's inverting input internally connected 1.25 reference voltage. noninverting input available input. This input used monitor input power supply resistive divider network. When voltage input drops below 1.25 comparator output (PFO) goes indicating power failure. early warning power failure, comparator used monitor preregulator input simply choosing appropriate resistive divider network. output used interrupt processor that shutdown procedure implemented before power lost.
INPUT POWER 1.25V POWER-FAIL INPUT POWER-FAIL OUTPUT
Figure Adding Hysteresis Power-Fail Comparator
1.251
1.25 1.25 1.25
VMID 1.25
VALID RESET BELOW
ADM706R/ADM706S/ADM706T, ADM708R/ADM708S/ ADM708T family products guaranteed provide valid reset level with Refer Typical Performance Characteristics section. drops below internal transistor does have sufficient drive hold voltage RESET longer held pull-down resistor shown Figure connected externally hold line required.
ADM706R/ADM706S/ ADM706T/ADM708R/ ADM708S/ADM708T
RESET
06435-012
Figure Power-Fail Comparator
ADDING HYSTERESIS POWER-FAIL COMPARATOR
increased noise immunity, hysteresis added power-fail comparator. Because comparator circuit noninverting, hysteresis added simply connecting resistor between output input shown Figure When low, Resistor sinks current from summing junction pin. When high, Resistor sources current into summing junction. This results differing trip levels comparator. Further noise immunity achieved connecting capacitor between GND.
06435-010
ADM706P/ADM706R/ ADM706S/ADM706T/ ADM708R/ADM708S/ ADM708T
Figure RESET Valid Below
Rev. Page
ADM708R/ADM708S/ADM708T
APPLICATIONS INFORMATION
typical operating circuit shown Figure unregulated input supply monitored using input resistive divider network. Resistor Resistor should selected that when supply voltage drops below desired level (for example, voltage drops below 1.25 threshold, thereby generating interrupt microprocessor. Monitoring preregulator input gives additional time execute orderly shutdown procedure before power lost.
UNREGULATED
MONITORING ADDITIONAL SUPPLY LEVELS
possible power-fail comparator monitor second supply shown Figure sensing resistors, selected such that voltage drops below 1.25 minimum acceptable input supply. output connected input that RESET generated when supply drops tolerance. this case, either supply drops tolerance, RESET generated.
+3V/+3.3V
ADM666A
3.3V
RESET
RESET MICROPROCESSOR
RESET
RESET LINE MICROPROCESSOR INTERRUPT
MANUAL RESET
Figure Monitoring V/3.3 Additional Supply,
06345-020
MICROPROCESSORS WITH BIDIRECTIONAL RESET
prevent contention microprocessors with bidirectional reset line, current limiting resistor should inserted between ADM706R/ADM706S/ADM706T, ADM708R/ADM708S/ ADM708T RESET output microprocessor reset pin. This limits current safe level there conflicting output reset levels. suitable resistor value reset output required other uses, should buffered shown Figure
+3V/+3.3V BUFFERED RESET
Figure Typical Application Circuit
Microprocessor activity monitored using input. This driven using output line from processor. software routines should toggle this line least once every seconds. problem occurs this line toggled, then goes nonmaskable interrupt generated. This interrupt routine used clear problem. event inactivity line, system reset required, output should connected input shown Figure
RESET RESET
06345-021
MICROPROCESSOR
Figure Bidirectional Input/Output RESET
Figure RESET from
Rev. Page
06345-023
ADM706R/ ADM706S/ ADM706T
ADM706R/ADM706S/ ADM706T/ADM708R/ ADM708S/ADM708T
RESET
MICROPROCESSOR
LINE
RESET
06345-022
ADM706R/ ADM706S/ ADM706T
ADM706R/ ADM706S/ ADM706T
ADM708R/ADM708S/ADM708T
OUTLINE DIMENSIONS
0.400 (10.16) 0.365 (9.27) 0.355 (9.02)
0.280 (7.11) 0.250 (6.35) 0.240 (6.10)
0.100 (2.54) 0.210 (5.33) 0.150 (3.81) 0.130 (3.30) 0.115 (2.92) 0.022 (0.56) 0.018 (0.46) 0.014 (0.36) 0.070 (1.78) 0.060 (1.52) 0.045 (1.14)
0.325 (8.26) 0.310 (7.87) 0.300 (7.62) 0.060 (1.52) 0.195 (4.95) 0.130 (3.30) 0.115 (2.92)
0.015 (0.38) SEATING PLANE 0.005 (0.13)
0.015 (0.38) GAUGE PLANE 0.430 (10.92)
0.014 (0.36) 0.010 (0.25) 0.008 (0.20)
COMPLIANT JEDEC STANDARDS MS-001 CONTROLLING DIMENSIONS INCHES; MILLIMETER DIMENSIONS PARENTHESES) ROUNDED-OFF INCH EQUIVALENTS REFERENCE ONLY APPROPRIATE DESIGN. CORNER LEADS CONFIGURED WHOLE HALF LEADS.
Figure 8-Lead Plastic Dual In-Line Package [PDIP] Narrow Body (N-8) Dimension shown inches (millimeters)
5.00 (0.1968) 4.80 (0.1890)
4.00 (0.1574) 3.80 (0.1497)
6.20 (0.2440) 5.80 (0.2284)
1.27 (0.0500) 0.25 (0.0098) 0.10 (0.0040) COPLANARITY 0.10 SEATING PLANE
1.75 (0.0688) 1.35 (0.0532)
0.50 (0.0196) 0.25 (0.0099) 0.25 (0.0098) 0.17 (0.0067) 1.27 (0.0500) 0.40 (0.0157)
0.51 (0.0201) 0.31 (0.0122)
COMPLIANT JEDEC STANDARDS MS-012-A CONTROLLING DIMENSIONS MILLIMETERS; INCH DIMENSIONS PARENTHESES) ROUNDED-OFF MILLIMETER EQUIVALENTS REFERENCE ONLY APPROPRIATE DESIGN.
Figure 8-Lead Standard Small Outline Package [SOIC_N] Narrow Body (R-8) Dimensions shown millimeters (inches)
Rev. Page
060506-A
070606-A
ADM708R/ADM708S/ADM708T
ORDERING GUIDE
Model ADM706PAN ADM706PANZ ADM706PAR ADM706PAR-REEL ADM706PARZ1 ADM706PARZ-REEL1 ADM706RAN ADM706RANZ1 ADM706RAR ADM706RAR-REEL ADM706RAR-REEL7 ADM706RARZ1 ADM706RARZ-REEL1 ADM706RARZ-REEL71 ADM706SAN ADM706SANZ1 ADM706SAR ADM706SAR-REEL ADM706SARZ1 ADM706SARZ-REEL1 ADM706TAN ADM706TANZ1 ADM706TAR ADM706TAR-REEL ADM706TARZ1 ADM706TARZ-REEL1 ADM708RAN ADM708RANZ1 ADM708RAR ADM708RAR-REEL ADM708RARZ1 ADM708RARZ-REEL1 ADM708SAN ADM708SANZ1 ADM708SAR ADM708SAR-REEL ADM708SARZ1 ADM708SARZ-REEL1 ADM708TAN ADM708TANZ1 ADM708TAR ADM708TAR-REEL ADM708TARZ1 ADM708TARZ-REEL1
Temperature Range -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C
Package Description 8-Lead PDIP 8-Lead PDIP 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead PDIP 8-Lead PDIP 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead PDIP 8-Lead PDIP 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead PDIP 8-Lead PDIP 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead PDIP 8-Lead PDIP 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead PDIP 8-Lead PDIP 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead PDIP 8-Lead PDIP 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N
Package Option
Pb-free part.
Rev. Page
ADM708R/ADM708S/ADM708T
NOTES
Rev. Page
ADM708R/ADM708S/ADM708T
NOTES
Rev. Page
ADM708R/ADM708S/ADM708T
NOTES
©2007 Analog Devices, Inc. rights reserved. Trademarks registered trademarks property their respective owners. D06435-0-2/07(B)
Rev. Page

ADM708R/ADM708S/ADM708T Precision supply voltage monitor 2.63 (AD

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