Microprocessor Supervisory Reset Circuits with Edge-Triggered, One-Sho
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19-2523; 11/05
Microprocessor Supervisory Reset Circuits with Edge-Triggered, One-Shot Manual Reset
MAX6467/MAX6468 microprocessor (µP) supervisory circuits monitor single power-supply voltages from +1.8V +5.0V assert reset supply voltage drops below preset threshold. edge-triggered, one-shot manual reset function ensures that enters reset mode fixed timeout period only, even event continuously asserted manual reset. MAX6467/MAX6468 significantly improve system reliability compared traditional manual reset supervisory circuits. variety factory-trimmed threshold options accommodate different supply voltages tolerances, eliminating external components. factory-set thresholds range from +1.575V +4.625V monitor +5.0V, +3.3V, +3.0V, +2.5V, +1.8V supplies with various tolerances. Reset timeout periods 150ms (min) 1200ms (min) available accommodate different platforms. single, active-low RESET output asserts when drops below threshold edge-triggered asserts low. RESET remains reset timeout period after rises above threshold fixed, one-shot timeout period after manual reset input falling edge. RESET remains valid long remains above +1V. Open-drain (MAX6467) push-pull (MAX6468) output options provide additional flexibility system design. MAX6467/MAX6468 offered space-saving 4-pin SOT143 package ultra-small 4-pin SC70 package specified over automotive (-40°C +125°C) temperature range.
Features
Precision Factory-Set Reset Threshold Voltages +5.0V, +3.3V, +3.0V, +2.5V, +1.8V Supplies Edge-Triggered Manual Reset Input with OneShot Pulsed Reset Output Reset Timeout Period Options (150ms 1200ms min) Immune Short Voltage Transients Supply Current (3µA +1.8V) RESET Valid Active-Low Open-Drain Push-Pull RESET Output Options -40°C +125°C Operating Temperature Range Small 4-Pin SC70 SOT143 Packages External Components Required Compatible with MAX811, MAX6315, MAX6384, MAX6386
MAX6467/MAX6468
Ordering Information
PART MAX6467XS_ _D_-T MAX6467US_ _D_-T MAX6468XS_ _D_-T MAX6468US_ _D_-T TEMP RANGE -40°C +125°C -40°C +125°C -40°C +125°C -40°C +125°C PIN-PACKAGE SC70-4 SOT143-4 SC70-4 SOT143-4
Applications
Cell Phones/PDAs Embedded Control Systems Industrial Equipment Automotive Products Portable/Battery-Powered Equipment Medical Devices Modems Players Systems Digital Cameras
Note: Insert reset threshold suffix (see Reset Threshold table) after Insert reset timeout delay (see Reset Timeout Delay table) after complete part number. Sample stock generally held standard versions only (see Standard Versions table). Standard versions have order increment requirement 2500 pieces. Nonstandard versions have order increment requirement 10,000 pieces. Contact factory availability. Devices available both leaded lead-free packaging. Specify lead-free replacing with "+T" when ordering.
Configurations
VIEW
RESET
MAX6467XS MAX6468XS
SC70
Typical Operating Circuit appears data sheet.
Configurations continued data sheet.
Maxim Integrated Products
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Microprocessor Supervisory Reset Circuits with Edge-Triggered, One-Shot Manual Reset MAX6467/MAX6468
ABSOLUTE MAXIMUM RATINGS
.-0.3V +6.0V RESET Open-Drain.-0.3V +6.0V Push-Pull.-0.3V (VCC 0.3V) .-0.3V (VCC 0.3V) Input/Output Current (all pins) .20mA Continuous Power Dissipation +70°C) 4-Pin SC70 (derate 3.1mW/°C above +70°C) .245mW 4-Pin SOT143 (derate 4mW/°C above +70°C).320mW Operating Temperature Range .-40°C +125°C Storage Temperature Range .-65°C +150°C Junction Temperature .+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 +125°C, unless otherwise noted. Typical values +25°C.) (Note
PARAMETER Operating Voltage Range SYMBOL CONDITIONS +125°C -40°C +5.5V, load Supply Current +3.6V, load +2.5V, load +1.8V, load Reset Threshold (See Reset Threshold Table) Reset Delay Reset Timeout Period Timeout Period Rising Debounce Period (Note +25°C -40°C +85°C +85°C +125°C tMRP tDEB Input Voltage Minimum Input Pulse Glitch Rejection RESET Delay Pullup Resistance RESET Output High (MAX6468 Only) +2.5V, ISOURCE 500µA, RESET asserted +4.5V, ISOURCE 800µA, RESET asserted falling 10mV/µs from 100mV 100mV option option options options 1200 -1.5% -2.5% 1800 2400 1500 2250 +1.5% +2.5% UNITS
Microprocessor Supervisory Reset Circuits with Edge-Triggered, One-Shot Manual Reset
ELECTRICAL CHARACTERISTICS (continued)
(VCC +1.2V +5.5V, -40°C +125°C, unless otherwise noted. Typical values +25°C.) (Note
PARAMETER SYMBOL CONDITIONS +1V, ISINK 80µA, RESET asserted RESET Output +2.5V, ISINK 1.2mA, RESET asserted +4.5V, ISINK 3.2mA, RESET asserted RESET Output Leakage Current (MAX6467 Only) ILKG RESET asserted UNITS
MAX6467/MAX6468
Note Specifications over temperature guaranteed design. Production testing +25°C only. Note input ignores falling edges that occur within rising debounce period (tDEB) after first rises from high (after valid reset assertion). This prevents invalid reset assertion switch bounce.
Typical Operating Characteristics
(VCC +5V, MAX6468US29D3 device, +25°C, unless otherwise noted.)
RESET DELAY TEMPERATURE
100mV 100mV
MAX6467 toc03
SUPPLY CURRENT TEMPERATURE
MAX6467 toc01
SUPPLY CURRENT SUPPLY VOLTAGE
SUPPLY CURRENT (µA) SUPPLY VOLTAGE
MAX6467 toc02
SUPPLY CURRENT (µA) +2.5V +1.8V +5.5V +3.6V
RESET DELAY (µs)
TEMPERATURE (°C)
TEMPERATURE (°C)
RESET TIMEOUT PERIOD TEMPERATURE
MAX6467 toc04
NORMALIZED RESET THRESHOLD TEMPERATURE
MAX6467 toc05
OUTPUT VOLTAGE SINK CURRENT
5.0V
MAX6467 toc06
RESET TIMEOUT PERIOD (ms)
1.010 NORMALIZED RESET THRESHOLD
(mV)
1.005
1.000
0.995
0.990 TEMPERATURE (°C) TEMPERATURE (°C)
ISINK (mA)
Microprocessor Supervisory Reset Circuits with Edge-Triggered, One-Shot Manual Reset MAX6467/MAX6468
Typical Operating Characteristics (continued)
(VCC +5V, MAX6468US29D3 device, +25°C, unless otherwise noted.)
OUTPUT VOLTAGE HIGH SOURCE CURRENT
MAX6467 toc07
MAXIMUM TRANSIENT DURATION RESET THRESHOLD OVERDRIVE
MAXIMUM TRANSIENT DURATION (µs)
MAX6467 toc08
+5.0V
RESET ASSERTS ABOVE THIS LINE
ISOURCE (mA)
RESET THRESHOLD OVERDRIVE (mV)
RESET DELAY TEMPERATURE
MAX6467 toc09
PROPAGATION DELAY (WITH 100mV OVERDRIVE)
MAX6467 toc10
RESET DELAY (ns)
3.0V 100mV/div AC-COUPLED 2.8V RESET 1V/div
TEMPERATURE (°C) 4µs/div
RESET PULLUP PULLDOWN RESPONSE
MAX6467 toc11
RESET TIMEOUT PERIOD
MAX6467 toc12
CRESET 47pF, RPULLUP 100k, VPULLUP 1.6V
1.675V 200mV/div 1.475V
3.3V 2V/div
1.6V RESET 500mV/div
3.3V RESET 2V/div
MAX6467_S16D3-T 40µs/div 40ms/div
Microprocessor Supervisory Reset Circuits with Edge-Triggered, One-Shot Manual Reset
Description
NAME RESET Ground Reset Output. RESET active-low open-drain (MAX6467) push-pull (MAX6468) output. RESET asserts when drops below selected threshold remains reset timeout period after rises above threshold. RESET one-shot asserts fixed reset timeout period falling edge manual reset input. open-drain output requires external pullup resistor. Manual Reset Input. Drive initiate reset output. controls edge-triggered one-shot that asserts RESET fixed timeout period when driven low. Internal timing circuitry ignores switch close open bounce ensure proper one-shot reset timing. Power-Supply Input. provides power device also monitored voltage. When drops below selected threshold, RESET asserts remains reset timeout period after rises above threshold. better noise immunity, bypass with 0.1µF capacitor. FUNCTION
MAX6467/MAX6468
SWITCH BOUNCE
SWITCH BOUNCE
SWITCH BOUNCE
RESET tMRP tDEB tMRP
Figure Timing Diagram
Detailed Description
Reset Output
MAX6467 provides active-low open-drain RESET output. MAX6468 provides active-low push-pull RESET output. RESET asserts drops below selected threshold falling edge occurs RESET remains reset timeout period after increases above threshold voltage one-shot pulsed timeout period after falling edge
Manual Reset Input
Many µP-based products require manual reset capability, allowing operator, test technician, external logic circuitry initiate reset. falling edge asserts
RESET low. RESET one-shot pulsed timeout period after falling edge internal 1.5k pullup resistor allows left unconnected used. driven with CMOSlogic levels, with open-drain/collector outputs. Connect normally open momentary pushbutton switch from realize manual reset function. External debounce circuitry required, MAX6467/ MAX6468 respond first falling edge ignore subsequent falling edges within reset timeout period during debounce period (see Figure After goes high 150ms (tDEB), manual reset one-shot ready trigger reset next falling edge. Connect 0.1µF capacitor from when using long cables provide additional noise immunity (Figure
Microprocessor Supervisory Reset Circuits with Edge-Triggered, One-Shot Manual Reset MAX6467/MAX6468
Reset Timeout Delay*
RESET TIMEOUT SUFFIX RESET TIMEOUT PERIOD (min/max) (ms) 150/300 1200/2400 TIMEOUT PERIOD (min/max) (ms) 150/300 150/300 RISING DEBOUNCE PERIOD (min/max) (ms) 150/300 150/300
*Additional reset timeout options available. Contact factory availability.
Applications Information
Falling Transients addition issuing reset during power-up, power-down, brownout conditions, MAX6467/ MAX6468 relatively immune short-duration falling transients (glitches). Typical Operating Characteristics section shows Maximum Transient Duration Overdrive which MAX6467/ MAX6468 generate reset pulse. This graph generated using falling pulse applied starting above actual reset threshold ending below threshold magnitude indicated (VCC Overdrive). graph indicates typical maximum pulse width falling transient have without initiating reset pulse. magnitude transient increases (goes
farther below reset threshold), maximum allowable pulse width decreases. 0.1µF bypass capacitor from provides additional transient immunity.
Ensuring Valid RESET Output Down
MAX6467/MAX6468 guarantee proper operation down +1V. applications that require valid reset levels down pulldown resistor active-low outputs (MAX6468 only, Figure ensures that RESET remains valid while RESET output longer sink current. This scheme does work with open-drain outputs MAX6467. Ensure that resistor value used does overload RESET output when above reset threshold. most applications, 100k
1.5k ONE-SHOT/ DEBOUNCE MAX6467 MAX6468
MAX6468
RESET 100k
RESET TIMEOUT PERIOD 1.23V
RESET OUTPUT
RESET
Figure RESET Valid
Chip Information
Figure Functional Diagram
TRANSISTOR COUNT: PROCESS: BiCMOS
Microprocessor Supervisory Reset Circuits with Edge-Triggered, One-Shot Manual Reset MAX6467/MAX6468
Standard Versions
PART MAX6467XS16D3 MAX6467XS22D3 MAX6467XS26D3 MAX6467XS29D3 MAX6467XS46D3 MAX6467US16D3 MAX6467US22D3 MAX6467US26D3 MAX6467US29D3 MAX6467US46D3 MAX6468XS16D3 MAX6468XS22D3 MAX6468XS26D3 MAX6468XS29D3 MAX6468XS46D3 MAX6468US16D3 MAX6468US22D3 MAX6468US26D3 MAX6468US29D3 MAX6468US46D3 MARK KAFN KAFO KAFP KAFQ KAFR KAFS KAFT KAFU KAEW KAFV
Reset Threshold (-40°C +85°C)
SUFFIX (min) 4.509 4.388 4.266 4.193 4.095 3.998 3.900 3.803 3.705 3.608 3.510 3.413 3.315 3.218 3.120 2.998 2.925 2.852 2.730 2.633 2.559 2.438 2.340 2.255 2.133 2.048 1.950 1.853 1.755 1.623 1.536 (typ) 4.625 4.500 4.375 4.300 4.200 4.100 4.000 3.900 3.800 3.700 3.600 3.500 3.400 3.300 3.200 3.075 3.000 2.925 2.800 2.700 2.625 2.500 2.400 2.313 2.188 2.100 2.000 1.900 1.800 1.665 1.575 (max) 4.741 4.613 4.484 4.408 4.305 4.203 4.100 3.998 3.895 3.793 3.690 3.588 3.485 3.383 3.280 3.152 3.075 2.998 2.870 2.768 2.691 2.563 2.460 2.370 2.242 2.153 2.050 1.948 1.845 1.707 1.614
Typical Operating Circuit
+1.0V +5.5V
MAX6467 MAX6468
RESET
RESET INPUT
Configurations (continued)
VIEW
RESET
MAX6467US MAX6468US SOT143
Microprocessor Supervisory Reset Circuits with Edge-Triggered, One-Shot Manual Reset MAX6467/MAX6468
Package Information
(The package drawing(s) this data sheet reflect most current specifications. latest package outline information, www.maxim-ic.com/packages.)
SOT-143 4L.EPS
PACKAGE OUTLINE, SOT-143,
21-0052
Microprocessor Supervisory Reset Circuits with Edge-Triggered, One-Shot Manual Reset
Package Information (continued)
(The package drawing(s) this data sheet reflect most current specifications. latest package outline information, www.maxim-ic.com/packages.)
SC70, 4L.EPS
MAX6467/MAX6468
PACKAGE OUTLINE, SC70
21-0098
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 2005 Maxim Integrated Products Printed registered trademark Maxim Integrated Products, Inc.
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