MAX803L资料

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19-0344; Rev 4; 12/99

3-Pin Microprocessor Reset Circuits

General Description

____________________________Features

The MAX803/MAX809/MAX810 are microprocessor (µP)supervisory circuits used to monitor the power suppliesoPrecision Monitoring of +2.5V, +3V, +3.3V, andin µP and digital systems. They provide excellent circuit+5V Power-Supply Voltages

reliability and low cost by eliminating external compo-oFully Specified Over Temperature

nents and adjustments when used with +5V, +3.3V,oAvailable in Three Output Configurations

+3.0V, or +2.5V-powered circuits.

Open-Drain RESETOutput (MAX803)These circuits perform a single function: they assert aPush-Pull RESET Output (MAX809)reset signal whenever the VCCsupply voltage declinesPush-Pull RESETOutput (MAX810)below a preset threshold, keeping it asserted for ato140ms min Power-On Reset Pulse Widthleast 140ms after Vold. Reset thresholds suitable for operation with a vari-CChas risen above the reset thresh-o12µA Supply Current

ety of supply voltages are available.

oGuaranteed Reset Valid to VCC= +1VThe MAX803 has an open-drain output stage, while theoPower Supply Transient ImmunityMAX809/MAX810 have push-pull outputs. TheoNo External Components

MAX803’s open-drain RESEToutput requires a pull-upo3-Pin SC70 and SOT23 Packages

resistor that can be connected to a voltage higher thanVOrdering Information

CC. The MAX803/MAX809 have an active-low RESEToutput, while the MAX810 has an active-high RESETPARTTEMP. RANGEPIN-PACKAGEoutput. The reset comparator is designed to ignore fastMAX803_EXR-T-40°C to +105°C3 SC70-3transients on VCC, and the outputs are guaranteed tobe in the correct logic state for VMAX803_EXR-T10-40°C to +105°C3 SC70-3CCdown to 1V.

MAX809_EXR-T-40°C to +105°C3 SC70-3Low supply current makes the MAX803/MAX809/MAX809_EXR-T10-40°C to +105°C3 SC70-3MAX810 ideal for use in portable equipment. TheMAX803 is available in a 3-pin SC70 package, and theMAX809_EUR-T-40°C to +105°C3 SOT23-3MAX809/MAX810 are available in 3-pin SC70 or SOT23MAX809_EUR-T10-40°C to +105°C3 SOT23-3packages.

MAX810_EXR-T-40°C to +105°C3 SC70-3ApplicationsMAX810_EXR-T10-40°C to +105°C3 SC70-3MAX810_EUR-T-40°C to +105°C3 SOT23-3ComputersMAX810_EUR-T10-40°C to +105°C3 SOT23-3Controllers

Note: These parts are offered in 2.5k or 10k reels, and must beIntelligent Instruments

ordered in 2.5k or 10k increments. Order MAX803_EXR-T forCritical µP and µC Power Monitoring2.5k reels and MAX803_EXR-T10 for 10k reels. Insert thePortable/Battery-Powered Equipmentdesired suffix letter from the Selector Guide into the blank tocomplete the part number. All versions of these products mayAutomotive

not be available at the time of announcement. Contact factory foravailability.

Typical Operating CircuitPin ConfigurationTOP VIEWVCCGND1VCCVCCRPULL-UP*MAX803MAX803MAX809µPMAX809RESETRESETMAX8103VCCINPUTRESET (RESET)2GNDGND( ) ARE FOR MAX810.SC70-3/SOT23-3*MAX803 ONLYMAX803 AVAILABLE IN SC70-3 ONLY.________________________________________________________________Maxim Integrated Products1

For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.For small orders, phone 1-800-835-8769.

MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z元器件交易网www.cecb2b.com

3-Pin Microprocessor Reset CircuitsMAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/ZABSOLUTE MAXIMUM RATINGS

Terminal Voltage (with respect to GND)

VCC....................................................................-0.3V to +6.0VRESET, RESET(push-pull).....................-0.3V to (VCC+ 0.3V)RESET(open drain)...........................................-0.3V to +6.0VInput Current, VCC..............................................................20mAOutput Current, RESET, RESET..........................................20mARate of Rise, VCC............................................................100V/µs

Continuous Power Dissipation (TA= +70°C)

3-Pin SC70 (derate 2.17mW/°C above +70°C)............174mW3-Pin SOT23 (derate 4mW/°C above +70°C)...............320mWOperating Temperature Range.........................-40°C to +105°CStorage Temperature Range.............................-65°C to +150°CLead Temperature (soldering, 10s).................................+300°C

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functionaloperation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure toabsolute maximum rating conditions for extended periods may affect device reliability.

(VCC= full range, TA= -40°C to +105°C, unless otherwise noted. Typical values are at TA= +25°C, VCC= 5V for L/M/J versions, VCC= 3.3V for T/S versions, VCC= 3V for R version, and VCC= 2.5V for Z version.) (Note 1)

PARAMETERVCCRange SYMBOLCONDITIONSTA= 0°C to +70°CTA= -40°C to +105°CTA= -40°C to+85°CTA= +85°C to+105°CTA= -40°C to+85°CTA= +85°C to+105°CMAX8_ _LVCC< 5.5V, MAX8_ _J/L/MVCC< 3.6V, MAX8_ _R/S/TVCC< 5.5V, MAX8_ _L/MVCC< 3.6V, MAX8_ _R/S/TVCC< 5.5V, MAX8_ _L/MVCC< 3.6V, MAX8_ _R/S/T/ZVCC< 5.5V, MAX8_ _L/MVCC< 3.6V, MAX8_ _R/S/T/ZTA= +25°CTA= -40°C to +85°CTA= +85°C to +105°CTA= +25°CMAX8_ _MTA= -40°C to +85°CTA= +85°C to +105°CMAX809J (SOT only)TA= +25°CTA= -40°C to +85°CTA= +85°C to +105°CTA= +25°CReset ThresholdVTHMAX8_ _TTA= -40°C to +85°CTA= +85°C to +105°CTA= +25°CMAX8_ _STA= -40°C to +85°CTA= +85°C to +105°CTA= +25°CMAX8_ _RTA= -40°C to +85°CTA= +85°C to +105°CMAX8_ _Z(SC70 only)TA= +25°CTA= -40°C to +85°CTA= +85°C to +105°C4.564.504.404.314.254.163.933.893.803.04 3.083.002.922.892.852.782.592.552.502.282.252.212.322.632.934.004.384.631612MIN1.01.22417TYPMAX5.55.56050100100353075754.704.754.864.454.504.564.064.104.203.113.153.232.963.003.082.662.702.762.352.382.45VµAUNITSVELECTRICAL CHARACTERISTICS

Supply Current (SOT23)ICCSupply Current (SC70)ICC2_______________________________________________________________________________________元器件交易网www.cecb2b.com

3-Pin Microprocessor Reset Circuits

ELECTRICAL CHARACTERISTICS (continued)

(V= 3.3V for T/S versions, VCC= full range, TA= -40°C to +105°C, unless otherwise noted. Typical values are at T= 3V for R version, and VA= +25°C, VCC= 5V for L/M/J versions, VCCCCCC= 2.5V for Z version.) (Note 1)

PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSReset Threshold Tempco30ppm/°CVCCto Reset Delay (Note 2)VCC= VTHto (VTH- 100mV)20µsReset Active Timeout PeriodTA= -40°C to +85°C140240560(SOT23)TA= +85°C to +105°C100840msReset Active Timeout PeriodTA= -40°C to +85°C140240460(SC70)TA= +85°C to +105°C100840msV= 1.2mA,RESETOutput Voltage LowCC= VTHmin, ISINKMAX803R/S/T/Z, MAX809R/S/T/Z0.3(push-pull active low and open-drain active-low, MAX803 andVOLVCC= VTHmin, ISINK= 3.2mA, 0.4VMAX809)MAX803L/M, MAX809J/L/MVCC> 1.0V, ISINK= 50µA0.3VCC > VTHmax, ISOURCE= 500µA,RESETOutput Voltage HighMAX809R/S/T/Z0.8VCC(push-pull active low, MAX809)VOHVVCC> VTHmax, ISOURCE= 800µA,MAX809J/L/MVCC- 1.5VCC= VTHmax, ISINK= 1.2mA,RESET Output Voltage LowVMAX810R/S/T/Z0.3(push-pull active high, MAX810)OLVVCC= VTHmax, ISINK= 3.2mA, MAX810L/M0.4RESET Output Voltage High(push-pull active high, MAX810)VOH1.8V < VCC< VTHmin, ISOURCE= 150µA0.8VCCVRESETOpen-Drain OutputLeakage Current (MAX803)VCC> VTH, RESETdeasserted1 µANote 1:Production testing done at TA= +25°C; limits over temperature guaranteed by design only. Note 2:RESEToutput for MAX803/MAX809; RESET output for MAX810.

Typical Operating Characteristics(VCC= full range, TA= -40°C to +105°C, unless otherwise noted. Typical values are at TA= +25°C, VCC= +5V for L/M/J versions,VCC= +3.3V for T/S versions, VCC= +3V for R version, and VCC= +2.5V for Z version.)

SUPPLY CURRENT vs. TEMPERATURE

POWER-DOWN RESET DELAY vs. (SC70 PACKAGE, NO LOAD)

TEMPERATURE (MAX8_ _R/S/T/Z)

15101003CcOoT-t V3OD = VTH - VCC30088XXAA)MMsMAX8_ _L/M, VCC = 5Vµ( 80)AYVOD = 10mVµAL( ET10

MAX8_ _R/S/T, VCC = 3.3VDN ET60

RERSEURVOD = 20mVC MAX8_ _Z, VCC = 2.5VNYLWPOD40

PU5

-SREWOP20VOD = 100mVMAX8_ _L/M/R/S/T/Z, VCC = 1V00

VOD = 200mV-40

-20

-40

-20

02040

TEMPERATURE (°C)

_______________________________________________________________________________________3

MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z元器件交易网www.cecb2b.com

3-Pin Microprocessor Reset CircuitsMAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/ZTypical Operating Characteristics (continued)(VCC= full range, TA= -40°C to +105°C, unless otherwise noted. Typical values are at TA= +25°C, VCC= +5V for L/M/J versions,VCC= +3.3V for T/S versions, VCC= +3V for R version, and VCC= +2.5V for Z version.)

POWER-DOWN RESET DELAY vs. TEMPERATURE (MAX8_ _J/L/M)

MAX803-TOC4POWER-UP RESET TIMEOUT

vs. TEMPERATURE

MAX803-TOC5NORMALIZED RESET THRESHOLD

vs. TEMPERATURE

MAX803-TOC6140POWER-DOWN RESET DELAY (µs)120100806040200-40

-20

VOD = VTH - VCCVOD = 10mV250POWER-UP RESET TIMEOUT (ms)1.0031.002NORMALIZED THRESHOLD1.0011.0000.9990.9980.997

-40

-20

245

MAX8_ _J/L/M240

MAX8_ _R/S/T/ZVOD = 20mV235

VOD = 100mVVOD = 200mV040TEMPERATURE (°C)

230225

-40

-20

TEMPERATURE (°C)

Selector GuidePART/SUFFIXMAX803LMAX803MMAX803TMAX803SMAX803RMAX803ZMAX809LMAX809MMAX809JMAX809TMAX809SMAX809RMAX809ZMAX810LMAX810MMAX810TMAX810SMAX810RMAX810Z4

RESET THRESHOLD (V)4.634.383.082.932.632.324.634.384.003.082.932.632.324.634.383.082.932.632.32OUTPUT TYPEOpen-Drain RESETOpen-Drain RESETOpen-Drain RESETOpen-Drain RESETOpen-Drain RESETOpen-Drain RESETPush-Pull RESETPush-Pull RESETPush-Pull RESETPush-Pull RESETPush-Pull RESETPush-Pull RESETPush-Pull RESETPush-Pull RESETPush-Pull RESETPush-Pull RESETPush-Pull RESETPush-Pull RESETPush-Pull RESETTOP MARKSOT——————AAAAABAACWAAACAAADAAAFAA—AGAAAHAAAJAAAKAAALAA—SC70AAZABAABBABCABDABEAANAAO—AAPAAQAARAASAATAAUAAVAAXAAWAAY_______________________________________________________________________________________

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3-Pin Microprocessor Reset Circuits

_____________________Pin Description

PINNAMEFUNCTION1GNDGroundVCCRESETRESETOutput remains low while VCC(MAX803/is below the reset threshold, and for atMAX809MAX809)least 140ms after VCCrises above theRESET2reset threshold.RESET Output remains high while VCCR1RESETis below the reset threshold, and for atGND100k(MAX810)least 140ms after VCCrises above thereset threshold.3VCCSupply Voltage (+5V, +3.3V, +3.0V, or+2.5V)Figure 2. RESETValid to VCC= Ground Circuit

Applications Information

400)TA = +25°CNegative-Going VCCTransients

sµ( NO320In addition to issuing a reset to the µP during power-up,ITpower-down, and brownout conditions, the MAX803/ARUMAX809/MAX810 are relatively immune to short-durationD T240Nnegative-going VCCtransients (glitches).

EISNFigure 1 shows typical transient duration vs. reset com-ART160 parator overdrive, for which the MAX803/MAX809/MUMMAX8_ _J/L/MMAX810 do notgenerate a reset pulse. The graph wasIXA80generated using a negative-going pulse applied to VCC,MMAX8_ _R/S/T/Zstarting 0.5V above the actual reset threshold and end-0ing below it by the magnitude indicated (reset compara-1101001000tor overdrive). The graph indicates the maximum pulseRESET COMPARATOR OVERDRIVE, VTH - VCC (mV)width a negative-going VCCtransient can have withoutcausing a reset pulse. As the magnitude of the transientFigure 1. Maximum Transient Duration Without Causing aincreases (goes farther below the reset threshold), theReset Pulse vs. Reset Comparator Overdrive

maximum allowable pulse width decreases. Typically, forthe MAX8__L and MAX8__M, a V100mV below the reset threshold and lasts 20µs or lessCCtransient that goeswill not cause a reset pulse. A 0.1µF bypass capacitormounted as close as possible to the VCCpin providesDetailed Description

additional transient immunity.

A microprocessor’s (µP’s) reset input starts the µP in aEnsuring a Valid Reset Output

known state. The MAX803/MAX809/MAX810 assertDown to VCC= 0

reset to prevent code-execution errors during power-When VCCfalls below 1V, the MAX809 RESEToutputup, power-down, or brownout conditions. They assert ano longer sinks current—it becomes an open circuit.reset signal whenever the VCCsupply voltage declinesTherefore, high-impedance CMOS logic inputs con-below a preset threshold, keeping it asserted for atnected to RESETcan drift to undetermined voltages.least 140ms after VCChas risen above the reset thresh-This presents no problem in most applications sinceold. The MAX803 uses an open-drain output, and themost µP and other circuitry is inoperative with VMAX809/MAX810 have a push-pull output stage.below 1V. However, in applications where RESETmustCCConnect a pull-up resistor on the MAX803’s RESETout-be valid down to 0V, adding a pull-down resistor toput to any supply between 0 and 6V.

RESETcauses any stray leakage currents to flow to

_______________________________________________________________________________________

MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z元器件交易网www.cecb2b.com

3-Pin Microprocessor Reset CircuitsMAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z+3.3V+5.0VVCCVCCVCCVCCRPULLUPVCCMAX803RESETRESETINPUTµPMOTOROLA68HCXX5V SYSTEMRESETINPUTMAX803RESETGNDGNDGNDGNDFigure 3. Interfacing to µPs with Bidirectional Reset I/O

Figure 4. MAX803 Open-Drain RESETOutput Allows Use withMultiple Supplies

ground, holding RESETlow (Figure 2). R1’s value is notcritical; 100kΩis large enough not to load RESETandsmall enough to pull RESETto ground.

A 100kΩpull-up resistor to VCCis also recommendedfor the MAX810 if RESET is required to remain valid forVCC< 1V.

Benefits of Highly Accurate

Reset Threshold

Most µP supervisor ICs have reset threshold voltagesbetween 5% and 10% below the value of nominal sup-ply voltages. This ensures a reset will notoccur within5% of the nominal supply, but will occur when the sup-ply is 10% below nominal.

When using ICs rated at only the nominal supply ±5%,this leaves a zone of uncertainty where the supply isbetween 5% and 10% low, and where the reset may ormay not be asserted.

The MAX8__L/T/Z use highly accurate circuitry toensure that reset is asserted close to the 5% limit, andlong before the supply has declined to 10% belownominal.

Interfacing to µPs with Bidirectional Reset Pins

Since the RESEToutput on the MAX803 is open drain,this device interfaces easily with µPs that have bidirec-tional reset pins, such as the Motorola 68HC11.Connecting the µP supervisor’s RESEToutput directlyto the microcontroller’s (µC’s) RESETpin with a singlepull-up resistor allows either device to assert reset(Figure 3).

MAX803 Open-Drain RESET Output Allows Use with Multiple Supplies

Generally, the pull-up connected to the MAX803 willconnect to the supply voltage that is being monitored atthe IC’s VCCpin. However, some systems may use theopen-drain output to level-shift from the monitored sup-ply to reset circuitry powered by some other supply(Figure 4). Note that as the MAX803’s VCCdecreasesbelow 1V, so does the IC’s ability to sink current atRESET. Also, with any pull-up, RESETwill be pulledhigh as VCCdecays toward 0. The voltage where thisoccurs depends on the pull-up resistor value and thevoltage to which it is connected.

___________________Chip Information

TRANSISTOR COUNT:275 (SOT23)

380 (SC70)

6_______________________________________________________________________________________

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3-Pin Microprocessor Reset Circuits

Package Information

SPE.L3 ,07CS_______________________________________________________________________________________7

MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z元器件交易网www.cecb2b.com

3-Pin Microprocessor Reset CircuitsMAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/ZPackage Information (continued)

SOTPO3L.EPSMaxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses areimplied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

Printed USA

is a registered trademark of Maxim Integrated Products.

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