Low-Power Dual-/Triple-Voltage SC70 Supervisory Circuits MAX6736-

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Low-Power Dual-/Triple-Voltage SC70 Supervisory Circuits MAX6736-

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19-2531; 4/03
Low-Power Dual-/Triple-Voltage SC70 Supervisory Circuits
MAX6736-MAX6745 low-power dual-/triplevoltage microprocessor (µP) supervisors. These devices assert reset monitored supply falls below factory-trimmed adjustable threshold maintain reset minimum timeout period after supplies rise above their thresholds. integrated dual/triple supervisory circuits significantly reduce size power compared separate discrete components. supply current makes these devices ideal portable equipment. MAX6736/MAX6737 dual fixed-voltage supervisors with manual reset input. MAX6738/ MAX6739 have fixed adjustable reset threshold manual reset input. MAX6740/ MAX6743 triple-voltage supervisors with fixed user-adjustable reset threshold inputs. MAX6741/MAX6744 dual-voltage supervisors with power-OK (POK) output ideal powersupply sequencing. MAX6742/MAX6745 monitor primary supply have independent power-fail comparator. MAX6736-MAX6745 monitor supply voltages CC1) from 1.8V 5.0V core supply voltages (VCC2) from 0.9V 3.3V with factory-trimmed reset threshold voltage options (Table external adjustable RSTIN input option allows monitoring voltages down 0.5V. variety push-pull open-drain reset outputs along with manual reset input power-fail input/output features available (see Selector Guide). MAX6736-MAX6745 offered space-saving 5-pin SC70 package operate over -40°C +85°C temperature range.
Features
Dual-/Triple-Supply Reset Voltage Monitors Precision Factory-Set Reset Thresholds Monitoring from 0.9V 5.0V Adjustable Reset Input Down 0.488V 150ms 1200ms (min) Reset Timeout Period Options VCC1 Power-OK Output Power-Supply Sequencing Applications (MAX6741/MAX6744) Power-Fail Input/Power-Fail Output (MAX6742/MAX6745) Supply Current Tiny SC70 Package
MAX6736-MAX6745
Ordering Information
PART MAX6736XK_ _D_-T MAX6737XK_ _D_-T TEMP RANGE -40°C +85°C -40°C +85°C PIN-PACKAGE SC70-5 SC70-5
Note: first placeholders threshold voltage levels devices. Desired threshold levels part number suffix found Tables after placeholder reset timeout period suffix found Table example, MAX6736XKLTD3-T dual-voltage supervisor VTH1 4.625V, VTH2 3.075V, 150ms minimum reset timeout period. devices available tape-and-reel only. There 2500-piece minimum order increment standard versions (see Table Sample stock typically held standard versions only. Nonstandard versions require minimum order increment 10,000 pieces. Contact factory availability.
Applications
Portable/BatteryPowered Equipment Multivoltage Systems Notebook Computers Controllers PDAs Equipment Equipment
Ordering Information continued data sheet. Selector Guide continued data sheet. Configurations appear data sheet. Typical Application Circuits appear data sheet. Functional Diagram appears data sheet.
Selector Guide
PART MAX6736 MAX6737 MAX6738 VOLTAGE MONITORS fixed fixed fixed, OPEN-DRAIN RESET PUSH-PULL RESET MANUAL RESET POWER-FAIL INPUT/ OUTPUT OUTPUT RSTIN INPUT
*Manual reset detect RESET output. Maxim Integrated Products
pricing, delivery, ordering information, please contact Maxim/Dallas Direct! 1-888-629-4642, visit Maxim's website www.maxim-ic.com.
Low-Power Dual-/Triple-Voltage SC70 Supervisory Circuits MAX6736-MAX6745
ABSOLUTE MAXIMUM RATINGS
VCC1, VCC2, POK1 .-0.3V Open-Drain RESET, GND.-0.3V Push-Pull RESET GND.-0.3V (VCC1 0.3V) RSTIN, GND.-0.3V (VCC1 0.3V) Input/Output Current, Pins .20mA Continuous Power Dissipation +70°C) 5-Pin SC70 (derate 3.1mW/°C above +70°C) .247mW Operating Temperature Range .-40°C +85°C Junction Temperature .+150°C Storage Temperature Range .-65°C +150°C Lead Temperature (soldering, 10s) .+300°C
Stresses beyond those listed under "Absolute Maximum Ratings" cause permanent damage device. These stress ratings only, functional operation device these other conditions beyond those indicated operational sections specifications implied. Exposure absolute maximum rating conditions extended periods affect device reliability.
ELECTRICAL CHARACTERISTICS
(VCC 1.2V 5.5V, -40°C +85°C, unless otherwise noted. Typical values +25°C.) (Note
PARAMETER Operating Voltage Range SYMBOL VCC1, VCC2 CONDITIONS -40°C +85°C VCC1 3.3V, VCC1 VCC2, load, reset asserted VCC1 Supply Current ICC1 VCC1 1.8V, VCC1 VCC2, load, reset asserted VCC2 1.8V, VCC2 VCC1, load, reset asserted VCC2 Supply Current ICC2 VCC2 3.3V, VCC2 VCC1, load, reset asserted MAX67_ MAX67_ MAX67_ MAX67_ Reset Threshold VCC1 VTH1 MAX67_ MAX67_ MAX67_ MAX67_ MAX67_ +85°C -40°C +85°C +85°C -40°C +85°C +85°C -40°C +85°C +85°C -40°C +85°C +85°C -40°C +85°C +85°C -40°C +85°C +85°C -40°C +85°C +85°C -40°C +85°C +85°C -40°C +85°C 4.500 4.425 4.250 4.175 3.000 2.950 2.850 2.800 2.550 2.505 2.250 2.213 2.125 2.088 1.620 1.593 1.530 1.503 1.575 1.665 2.188 2.313 2.625 2.925 3.075 4.375 4.625 4.750 4.825 4.500 4.575 3.150 3.200 3.000 3.050 2.700 2.745 2.375 2.413 2.250 2.288 1.710 1.737 1.620 1.647 UNITS
Low-Power Dual-/Triple-Voltage SC70 Supervisory Circuits
ELECTRICAL CHARACTERISTICS (continued)
(VCC 1.2V 5.5V, -40°C +85°C, unless otherwise noted. Typical values +25°C.) (Note
PARAMETER SYMBOL MAX67_ MAX67_ MAX67_ MAX67_ MAX67_ MAX67_ Reset Threshold VCC2 VTH2 MAX67_ MAX67_ MAX67_ MAX67_ MAX67_ MAX67_ MAX67_ RSTIN Threshold (MAX6738/ MAX6739/MAX6740/MAX6743) RSTIN Input Current Reset Threshold Hysteresis VTH-RSTIN CONDITIONS +85°C -40°C +85°C +85°C -40°C +85°C +85°C -40°C +85°C +85°C -40°C +85°C +85°C -40°C +85°C +85°C -40°C +85°C +85°C -40°C +85°C +85°C -40°C +85°C +85°C -40°C +85°C +85°C -40°C +85°C +85°C -40°C +85°C +85°C -40°C +85°C 85°C -40°C +85°C 3.000 2.905 2.850 2.800 2.550 2.505 2.250 2.213 2.125 2.088 1.620 1.593 1.530 1.503 1.350 1.328 1.275 1.253 1.080 1.062 1.020 1.002 0.810 0.797 0.765 0.752 0.476 0.468 0.488 0.788 0.833 1.050 1.110 1.313 1.388 1.575 1.665 2.188 2.313 2.625 2.925 3.075 3.150 3.050 3.000 3.050 2.700 2.745 2.375 2.413 2.250 2.288 1.710 1.737 1.620 1.647 1.425 1.448 1.350 1.373 1.140 1.158 1.080 1.098 0.855 0.869 0.810 0.824 0.500 0.507 UNITS
MAX6736-MAX6745
+85°C -40°C +85°C VRSTIN 0.1V (Note VTH1, VTH2, RSTIN, VCC1 1.0V, ISINK 50µA, +85°C
RESET, POK1 Output
VCC1 1.2V, ISINK 100µA VCC1 2.13V, ISINK 1.2mA VCC1 4.25V, ISINK 3.2mA, VCC1 2.38V, ISOURCE 500µA, output deasserted
RESET Output High (Push-Pull)
VCC1 4.75V, ISOURCE 800µA, output deasserted
Low-Power Dual-/Triple-Voltage SC70 Supervisory Circuits MAX6736-MAX6745
ELECTRICAL CHARACTERISTICS (continued)
(VCC 1.2V 5.5V, -40°C +85°C, unless otherwise noted. Typical values +25°C.) (Note
PARAMETER RESET Output Open-Drain Leakage Current (MAX6736/MAX6738) POK1 Output Open-Drain Leakage Reset Delay Reset Timeout Period (Note VCC1 Internal Pullup Impedance Timeout Period Minimum Input Pulse Width Glitch Rejection Input Voltage RESET Delay VCC1 POWER-OK OUTPUT (MAX6741/MAX6744 only) POK1 Timeout Period RESET VCC1 Internal Pullup Impedance Manual Reset Detect Debounce Period Manual Reset Timeout Period (Note Manual Reset Minimum Input Pulse Width Manual Reset Release Detect Threshold Manual Reset Glitch Rejection Manual Reset RESET Delay tDEB tMRP tMPW (Note MAX67_ MAX67_ (Note (Note (Note tPOKP 37.5 56.25 75.0 PUSHBUTTON RESET (MAX6740/MAX6741/MAX6742 only) 37.5 1200 VCC1 56.25 1800 75.0 2400 VCC1 tMRP tMPW Both timing options SYMBOL ILKG CONDITIONS Output asserted (Note UNITS
Output asserted (Note VCC1, VCC2, RSTIN falling 10mV/µs from 100mV 100mV MAX67_ MAX67_ 1200 1800
2400
MANUAL RESET (MAX6736-MAX6739 only) 0.75 VCC1 3.00
Low-Power Dual-/Triple-Voltage SC70 Supervisory Circuits
ELECTRICAL CHARACTERISTICS (continued)
(VCC 1.2V 5.5V, -40°C +85°C, unless otherwise noted. Typical values +25°C.) (Note
PARAMETER SYMBOL CONDITIONS +85°C -40°C +85°C VPFI 0.1V (Note VCC1 1.53V, ISINK 500µA Output VCC1 2.03V, ISINK 1.2mA VCC1 4.25V, ISINK 3.2mA falling 10mV/µs from VTH-PFI 100mV VTH-PFI 100mV rising 10mV/µs from VTH-PFI 100mV VTH-PFI 100mV (Note output valid (Note 0.476 0.468 0.488 0.500 0.507 UNITS POWER-FAIL COMPARATOR (MAX6742/MAX6745 only) Power Fail Threshold (Note Power Fail Current VTH-PFI IPFI
MAX6736-MAX6745
Propagation Delay
Startup Delay
Note Note Note Note Note
devices 100% tested +25°C. temperature limits guaranteed design. Guaranteed design. timeout period begins after POK1 timeout period (tPOKP) VCC2 VTH2 (max) (MAX6741/MAX6744). Refers manual reset function obtained forcing RESET output low. VCC1 1.6V.
Typical Operating Characteristics
+25°C, unless otherwise noted.)
SUPPLY CURRENT TEMPERATURE
MAX6736-45 toc01
SUPPLY CURRENT TEMPERATURE
MAX6736-45 toc02
SUPPLY CURRENT TEMPERATURE
SUPPLY CURRENT (µA) ICC2 ICC1 TOTAL VCC1 1.8V, VCC2 1.2V
MAX6736-45 toc03
SUPPLY CURRENT (µA) TEMPERATURE (°C) ICC2 TOTAL ICC1 VCC1 3.3V, VCC2 2.5V
SUPPLY CURRENT (µA) TEMPERATURE (°C) ICC2 TOTAL ICC1 VCC1 2.5V, VCC2 1.8V
TEMPERATURE (°C)
Low-Power Dual-/Triple-Voltage SC70 Supervisory Circuits MAX6736-MAX6745
Typical Operating Characteristics (continued)
+25°C, unless otherwise noted.)
NORMALIZED VCC/POK1/MR TIMEOUT PERIOD TEMPERATURE
MAXIMUM VCC1/VCC2 TRANSIENT DURATION (µs) 1.019 NORMALIZED VCC/POK1/MR RESET TIMEOUT PERIOD 1.014 1.009 1.004 0.999 0.994 0.989 0.984 TEMPERATURE (°C)
MAX6736-45 toc04
MAXIMUM VCC1/VCC2 TRANSIENT DURATION RESET THRESHOLD OVERDRIVE
MAX6736-45 toc05
10,000
1000
VCC1 RESET OCCURS ABOVE THESE LINES
VCC2
RESET THRESHOLD OVERDRIVE (mV) 1000
NORMALIZED RESET THRESHOLD TEMPERATURE
MAX6736-45 toc06
RESET OUTPUT DELAY TEMPERATURE
48.5 100mV OVERDRIVE
MAX6736-45 toc07
1.008 NORMALIZED RESET THRESHOLD
1.003
RESET OUTPUT DELAY (µs)
43.5
0.998
38.5
0.993 NORMALIZED +25°C 0.988 TEMPERATURE (°C)
33.5
28.5 TEMPERATURE (°C)
RESET INPUT RESET OUTPUT DELAY TEMPERATURE
MAX6736-45 toc08
POWER-FAIL INPUT POWER-FAIL OUTPUT DELAY TEMPERATURE
RISING EDGE 100mV OVERDRIVE
MAX6736-45 toc09
RSTIN RESET OUTPUT DELAY (µs)
100mV OVERDRIVE
DELAY (µs)
TEMPERATURE (°C)
FALLING EDGE
TEMPERATURE (°C)
Low-Power Dual-/Triple-Voltage SC70 Supervisory Circuits
Typical Operating Characteristics (continued)
+25°C, unless otherwise noted.)
MAX6736-MAX6745
RESET OUTPUT DELAY
MAX6736-45 toc10
POWER-FAIL INPUT POWER-FAIL OUTPUT DELAY
MAX6736-45 toc11
2V/div
200mV/div
VRESET 2V/div
2V/div
100ns/div
10µs/div
RESET OUTPUT DELAY
MAX6736-45 toc12
OUTPUT VOLTAGE SINK CURRENT
3.3V 200mV/div AC-COUPLED OUTPUT VOLTAGE (mV)
MAX6736-45 toc13
VRESET 2V/div
4µs/div SINK CURRENT (mA)
OUTPUT HIGH VOLTAGE SOURCE CURRENT
3.3V OUTPUT HIGH VOLTAGE
MAX6736-45 toc14
0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 SOURCING CURRENT (mA)
Low-Power Dual-/Triple-Voltage SC70 Supervisory Circuits MAX6736-MAX6745
Description
MAX6736 MAX6738 MAX6740 MAX6741 MAX6742 MAX6737 MAX6739 MAX6743 MAX6744 MAX6745 NAME FUNCTION Reset Output, Push-Pull Open Drain Active Low. RESET changes from high when monitored power-supply input (VCC1, VCC2, RSTIN) drops below selected reset threshold. remains until monitored power-supply inputs exceed their selected reset thresholds reset timeout period. RESET forced least minimum input pulse width. remains reset timeout period after goes high. pushpull output referenced VCC1. MAX6736/MAX6738 open-drain outputs require external pullup resistor. MAX6740/MAX6741/MAX6742 open-drain outputs have internal pullup resistor VCC1 provide manual reset function. Ground Manual Reset, Active Low. Pull least minimum input pulse width force RESET low. Reset remains active long reset timeout period after goes high. There internal 1.5k pullup resistor VCC1. Voltage Input Power supply input secondary voltage reset monitor. Adjustable Reset Threshold Input. RESET asserted when RSTIN below internal 0.488V reference level. adjustable reset threshold with external resistor-divider network. Connect RSTIN VCC1 unused. Voltage Input Power supply input primary voltage reset monitor. Power-Fail Comparator Input. asserted when below 0.488V. deasserted without reset timeout period when goes above 0.488V. Connect external resistor network desired monitor threshold. Power-Fail Comparator Output, Open Drain Active Low. asserted when below 0.488V. VCC1 Power-OK Output, Open Drain Active High. POK1 remains long VCC1 below VTH1. POK1 output goes high after VCC1 exceeds VTH1 POK1 timeout period. POK1 logic independent VCC2 inputs. output used control VCC1-to-VCC2 supply sequencing.
RESET
VCC2
RSTIN
VCC1
POK1
Low-Power Dual-/Triple-Voltage SC70 Supervisory Circuits
Table Reset Voltage Threshold Suffix Guide MAX6736/MAX6737/MAX6740/ MAX6741/MAX6743/MAX6744
PART SUFFIX VCC1 NOMINAL VOLTAGE THRESHOLD 4.625 4.375 4.375 3.075 3.075 3.075 3.075 3.075 2.925 2.925 2.925 2.925 2.925 2.625 2.625 2.625 2.625 VCC2 NOMINAL VOLTAGE THRESHOLD 3.075 2.925 2.625 2.313 1.665 1.388 1.110 0.833 2.188 1.575 1.313 1.050 0.788 2.188 1.575 1.313 1.050 PART SUFFIX VCC1 NOMINAL VOLTAGE THRESHOLD 2.625 2.313 2.313 2.313 2.313 2.188 2.188 2.188 2.188 1.665 1.665 1.665 1.665 1.575 1.575 1.575 1.575 VCC2 NOMINAL VOLTAGE THRESHOLD 0.788 1.665 1.388 1.110 0.833 1.575 1.313 1.050 0.788 3.075 1.388 1.110 0.833 2.625 1.313 1.050 0.788
MAX6736-MAX6745
Note: Standard versions, shown bold, available timeout option only. Samples typically held standard versions only. There 10,000-piece order increment nonstandard versions. Other threshold voltage combinations available; contact factory availability.
Table Reset Voltage Threshold Suffix Guide MAX6738/MAX6739/MAX6742/ MAX6745
PART SUFFIX VCC1 NOMINAL VOLTAGE THRESHOLD 4.625 4.375 3.075 2.925 2.625 2.313 2.188 1.665 1.575
Table Timeout Period Suffix Guide
TIMEOUT PERIOD SUFFIX ACTIVE TIMEOUT PERIOD (ms) 1200 (ms) 2400
Note: Standard versions, shown bold, available timeout option only. Samples typically held standard versions only. There 10,000-piece order increment nonstandard versions. Other threshold voltages available; contact factory availability.
Low-Power Dual-/Triple-Voltage SC70 Supervisory Circuits MAX6736-MAX6745
VCC1 VTH1
POK1 tPOKP
VCC2 VTH2
SWITCH BOUNCE
SWITCH BOUNCE
RESET
tMRP
Figure Timing Diagram
Detailed Description
Supply Voltages
MAX6736-MAX6745 supervisory circuits maintain system integrity alerting fault conditions. These devices optimized systems that monitor three supply voltages. reset output state guaranteed remain valid while either VCC1 VCC2 above 1.2V.
Reset Output
MAX6736-MAX6745 provide active-low reset output (RESET). RESET asserted when voltage either VCC1 VCC2 falls below voltage threshold level, RSTIN drops below threshold, pulled low. Once reset asserted, stays reset timeout period. VCC1, VCC2, RSTIN goes below reset threshold before reset timeout period completed, internal timer restarts. MAX6736/MAX6738/ MAX6740/MAX6741/MAX6742 have open-drain reset outputs, while MAX6745 have push-pull reset outputs (Figure MAX6740/MAX6741/MAX6742 include RESET output with manual reset detect function. opendrain RESET output internal pullup RESET output while output pulled remains least manual reset timeout period after external pulldown
Threshold Levels
MAX6744 input voltage threshold combinations indicated two-letter code Table MAX6738/ MAX6739/MAX6742/MAX6745 input voltage thresholds indicated one-letter code Table Contact factory availability other voltage thresholds.
Low-Power Dual-/Triple-Voltage SC70 Supervisory Circuits MAX6736-MAX6745
SWITCH BOUNCE OPEN PUSHBUTTON SWITCH CLOSED SWITCH BOUNCE SWITCH BOUNCE SWITCH BOUNCE
VCC1 tDEB RESET tMRP tDEB tMRP
Figure MAX6740/MAX6741/MAX6742 Manual Reset Timing Diagram
released. manual reset detect function internally debounced tDEB timeout period, output connected directly momentary pushbutton switch, desired (Figure
Manual Reset Input
Many microprocessor-based products require manual reset capability, allowing operator, test technician, external logic circuitry initiate reset while monitored supplies remain above their reset thresholds. MAX6736-MAX6739 have dedicated active-low input. RESET asserted while held remains asserted manual reset timeout period after returns high. input internal 1.5k pullup resistor VCC1 left unconnected used. driven with CMOS logic levels, open-drain/open-collector outputs, momentary pushbutton switch create manual reset function.
cally 488mV. Connect resistor-divider network circuit shown Figure establish externally controlled threshold voltage, VEXT_TH. VEXT_TH 0.488V((R1 leakage current RSTIN allows largevalued resistors, resulting reduced power consumption system.
Power-Fail Comparator
noninverting input auxiliary comparator. 488mV internal reference (VTH-PFI) connected inverting input comparator. less than 488mV, asserted low. deasserts without timeout period when rises above externally threshold. Common uses power-fail comparator include monitoring battery conditions failing DC-DC converter input voltage (see Typical Application Circuits). asserted output place system low-power suspend mode support orderly system shutdown before monitored voltages drop below reset thresholds. Connect external resistor-divider network shown Figure desired trip threshold. Connect VCC1 unused.
Adjustable Input Voltage
MAX6738/MAX6739 MAX6740/MAX6743 provide additional input monitor second third system voltage. threshold voltage RSTIN typi-
Applications Information
VEXT_TH RSTIN
MAX6738 MAX6739 MAX6740 MAX6743
Interfacing with Bidirectional Reset Pins
Most microprocessors with bidirectional reset pins interface directly open-drain RESET output options. Systems simultaneously requiring push-pull RESET output bidirectional reset interface logic contention. prevent contention, connect 4.7k resistor between RESET µP's reset port shown Figure
Figure Monitoring Additional Voltage
Low-Power Dual-/Triple-Voltage SC70 Supervisory Circuits MAX6736-MAX6745
POSITIVE
VEXT_TH
MAX6742 MAX6745
VEXT_TH VTH-PFI
NEGATIVE
MAX6742 MAX6745
VEXT_TH
(VTH-PFI)
shown Figure Select values such that sees VTH-PFI (488mV) when VEXT falls power-fail trip point (VFAIL) when VEXT rises power-good trip point (VGOOD). hysteresis window extends between specified VFAIL VGOOD thresholds. adds additional hysteresis sinking current from R1/R2 divider network when output logic sourcing current into network when logic high. typically order magnitude greater than current through should least ensure that 10nA (max) input current does significantly shift trip points. Therefore, most applications: VTH-PFI 0.488V 488k open-drain output requiring external pullup resistor, Select less than VGOOD DESIRED VEXT GOOD VOLTAGE THRESHOLD VFAIL DESIRED VEXT FAIL VOLTAGE THRESHOLD VPULLUP (FOR OPEN-DRAIN PFO) 488k (FOR >1µA CURRENT)
VPFI 488mV
VEXT_TH
Figure Using Power-Fail Input Monitor Additional Power Supply
(VGOOD VTH-PFI
(VTH- (VGOOD VFAIL
Adding Hysteresis Power-Fail Comparator
power-fail comparator typical input hysteresis 2.5mV. This sufficient most applications which power-supply line being monitored through external voltage-divider. additional noise margin desired, connect resistor between PFI,
VPU) (VGOOD VFAIL) 0.01
Power Sequencing Applications
Many dual-voltage processors/ASICs require specific power-up/power-down sequences core supplies.
VCC1 VCC2
RESET OTHER SYSTEM COMPONENTS
VPULLUP
VGOOD VFAIL
VCC2 VCC1
MAX6737 MAX6739 MAX6743 MAX6744 RESET MAX6745
VEXT
MAX6742 MAX6745
4.7k RESET
VGOOD DESIRED VEXT GOOD VOLTAGE THRESHOLD VFAIL DESIRED VEXT FAIL VOLTAGE THRESHOLD VCC1 (FOR PUSH-PULL PFO) 200k (FOR 2.5µA CURRENT) ((VGOOD VTH-PFI) (VTH-PFI)(VGOOD VFAIL) VPU) VTH-PFI VOH) (VGOOD VFAIL)
Figure Interfacing with Bidirectional Reset
Figure Adding Hysteresis Power Fail Push-Pull
Low-Power Dual-/Triple-Voltage SC70 Supervisory Circuits
MAX6741/MAX6744 offer VCC1 (POK1) ideal VCC1-to-VCC2 sequencing. POK1 remains long VCC1 below VTH1 threshold. When VCC1 exceeds VTH1 POK1 timeout period (tPOKP), open-drain POK1 output deasserted. POK1 output then enable VCC2 power supply (use external POK1 pullup resistor). RESET deasserted when both VCC1 VCC2 remain above their selected thresholds reset timeout period (tRP). POK1 output used before core core before sequencing, depending selected VCC1/VCC2 thresholds. Typical Application Circuit Figure
Transient Immunity
MAX6736-MAX6745 supervisors relatively immune short-duration falling transients (glitches). usually undesirable reset when experiences only small glitches. Typical Operating Characteristics show Maximum VCC1/VCC2 Transient Duration Reset Threshold Overdrive, which reset pulses generated. graph shows maximum pulse width that falling transient might typically have without causing reset pulse issued. amplitude transient increases, maximum allowable pulse width decreases. 0.1µF bypass capacitor mounted close provides additional transient immunity.
MAX6736-MAX6745
Monitoring Negative Voltage
power-fail comparator used monitor negative supply voltage using circuit shown Figure When negative supply valid, low. When negative supply voltage drops, goes high. circuit's accuracy affected threshold tolerance, VCC,
Chip Information
TRANSISTOR COUNT: PROCESS: BiCMOS
Functional Diagram
VCC1
MAX6736- MAX6745
POK1 VCC1 VCC2
DELAY
RSTIN/PFI
RESET TIMEOUT PERIOD
RESET OUTPUT RESET
VCC2 VCC1
PULLUP
0.488V
VCC1 1.23V
Low-Power Dual-/Triple-Voltage SC70 Supervisory Circuits MAX6736-MAX6745
Selector Guide (continued)
PART MAX6739 MAX6740 MAX6741 MAX6742 MAX6743 MAX6744 MAX6745 VOLTAGE MONITORS fixed, fixed, fixed fixed fixed, 1adj fixed fixed OPEN-DRAIN RESET PUSH-PULL RESET MANUAL RESET POWER-FAIL INPUT/ OUTPUT OUTPUT RSTIN INPUT
*Manual reset detect RESET output.
Typical Application Circuits
DC/DC CONVERTER UNREGULATED VBATT DC/DC CONVERTER
DC/DC CONVERTER SHDN VCC2 VCC1 CORE SUPPLY SUPPLY
VCC1 MAX6742
RESET
MAX6741
RESET
POK1
RESET
RESET
PUSHBUTTON SWITCH
PUSHBUTTON SWITCH
Low-Power Dual-/Triple-Voltage SC70 Supervisory Circuits
Configurations
VIEW
MAX6736-MAX6745
RESET
VCC1
RESET
VCC1
RESET
VCC1
MAX6736 MAX6737
VCC2
MAX6738 MAX6739
RSTIN
MAX6740 MAX6743
VCC2
RSTIN
SC70
SC70
SC70
RESET
VCC1
RESET
VCC1
MAX6741 MAX6744
VCC2
MAX6742 MAX6745
POK1
SC70
SC70
Ordering Information (continued)
PART MAX6738XK_D_-T MAX6739XK_D_-T MAX6740XK_ _D_-T MAX6741XK_ _D_-T MAX6742XK_D_-T MAX6743XK_ _D_-T MAX6744XK_ _D_-T MAX6745XK_D_-T TEMP 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 PIN-PACKAGE SC70-5 SC70-5 SC70-5 SC70-5 SC70-5 SC70-5 SC70-5 SC70-5
Low-Power Dual-/Triple-Voltage SC70 Supervisory Circuits MAX6736-MAX6745
Package Information
(The package drawing(s) this data sheet reflect most current specifications. latest package outline information, www.maxim-ic.com/packages.)
SC70, 5L.EPS
Maxim cannot assume responsibility circuitry other than circuitry entirely embodied Maxim product. circuit patent licenses implied. Maxim reserves right change circuitry specifications without notice time.
_Maxim Integrated Products, Gabriel Drive, Sunnyvale, 94086 408-737-7600 2003 Maxim Integrated Products Printed registered trademark Maxim Integrated Products.

Low-Power Dual-/Triple-Voltage SC70 Supervisory Circuits MAX6736-

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