19-1946; Rev 1; 2/01
4-Pin, Low-Power
µP Reset Circuits with Manual Reset
General Description
Features
The MAX6803/MAX6804/MAX6805 microprocessor (µP)supervisory circuits monitor the power supplies in 2.85VoUltra-Low 0.7V Operating Supply Voltage
to 5.0V µP and digital systems. They increase circuitoLow 4.0µA Supply Current
reliability and reduce cost by eliminating external com-ponents and adjustments. They also feature aoPrecision Monitoring of 2.85V to 5.0V Power-debounced manual reset input.
Supply Voltages
These devices perform a single function: they assert aoReset Thresholds Available from 2.63V to 4.80V,reset signal whenever the Vin Approximately 100mV Incrementsbelow a preset threshold or whenever manual reset isCCsupply voltage declinesoDebounced Manual Reset Inputasserted. Reset remains asserted for a preset timeoutperiod after VoFully Specified over Temperature
CChas risen above the reset threshold orafter manual reset is deasserted. The only differenceoThree Power-On Reset Timeout Periods Availableamong the three devices is their output. The MAX6804(1ms min, 20ms min, 100ms min)(push/pull) and MAX6805 (open-drain) have an active-oLow Cost
low RESEToutput, while the MAX6803 (push/pull) hasan active-high RESET output. The MAX6803/MAX6804oThree Available Output Structures: Push/Pull are guaranteed to be in the correct state for VCCdownRESET, Push/Pull RESET, Open-Drain RESETto 0.7V. The MAX6805 is guaranteed to be in the cor-oGuaranteed RESET/RESETValid to VCC= 0.7Vrect state for VCCdown to 1.0V.
(MAX6803/MAX6804)
The reset comparator in these ICs is designed to ignorefast transients on VoPower-Supply Transient Immunitytrimmable between 2.63V and 4.80V, in approximatelyCC. Reset thresholds are factory-oNo External Components Required100mV increments. These devices are available with ao4-Pin SOT143 Package
1ms min, 20ms min, or 100ms min reset timeout period.Ideal for space-critical applications, the MAX6803/oPin Compatible with MAX811/MAX812 andMAX6804/MAX6805 come packaged in a 4-pinMAX6314/MAX6315
SOT143. For a lower threshold voltage version, see theMAX6335/MAX6336/MAX6337.
ApplicationsOrdering InformationComputersPART*TEMP. RANGEPIN-PACKAGEControllers
MAX6803US_ _D_-T-40°C to +125°C4 SOT143Intelligent Instruments
MAX6804US_ _D_-T-40°C to +125°C4 SOT143Critical µP/µC Power MonitoringMAX6805US_ _D_-T-40°C to +125°C4 SOT143Portable/Battery-Powered Equipment*These devices are available in factory-set VCCreset thresh-Automotive
olds from 2.63V to 4.80V, in approximately 0.1V increments.Choose the desired reset threshold suffix from Table 1 andinsert it in the blanks following “US” in the part number.Factory-programmed reset timeout periods are also available.Insert the number corresponding to the desired nominal resettimeout period (1 = 1ms min, 2 = 20ms min, 3 = 100ms min) inthe blank following “D” in the part number. There are 15 stan-dard versions with a required order increment of 2500 pieces.Sample stock is generally held on the standard versions onlyTypical Operating Circuit and Pin Configuration appear(see Selector Guide). Contact the factory for availability of non-at end of data sheet.
standard versions (required order increment is 10,000 pieces).All devices available in tape-and-reel only.
Selector Guide appears at end of data sheet.
________________________________________________________________Maxim Integrated Products1
For pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-42, or visit Maxim’s website at www.maxim-ic.com.
MAX6803/MAX6804/MAX6805元器件交易网www.cecb2b.com
4-Pin, Low-Power
µP Reset Circuits with Manual ResetMAX6803/MAX6804/MAX6805ABSOLUTE MAXIMUM RATINGS
Terminal Voltage (with respect to GND)
VCC......................................................................-0.3V to +6VPush/Pull RESET or RESET, MR............-0.3V to (VCC+ 0.3V)Open-Drain RESET..............................................-0.3V to +6VInput Current (VCC).............................................................20mAOutput Current (RESET, RESET).........................................20mA
Continuous Power Dissipation (TA= +70°C)
4-Pin SOT143 (derate 4mW/°C above +70°C)............320mWOperating Temperature Range.........................-40°C to +125°CJunction Temperature......................................................+150°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.
ELECTRICAL CHARACTERISTICS
(VCC= full range, TA= -40°C to +125°C, unless otherwise noted. Typical values are at VCC= +5.0V and TA= +25°C, reset not asserted.) (Note 1)PARAMETERSupply Voltage Range(Note 1)SYMBOLCONDITIONSTA = 0°C to +125°CVCCTA = -40°C to +125°CICCNo loadMAX6803/MAX6804MAX6805MAX6803/MAX6804MAX6805VCC = +3.0VVCC = +5.0VTA = +25°C - 40°C to + 125°C TA = VTH- 1.8%VTH- 3%1201001500.1VILVIHISINK = 50µA, VCC ≥ 1.0VISINK = 1.2mA, VCC ≥ 2.5VISINK = 3.2mA, VCC ≥ 4.25VISOURC 500µA, VCC ≥ 3.0VE = ISOURC 800µA, VCC ≥ 5.0VE = 0.8 ✕ VCC0.8 ✕ VCC0.7 ✕ VCC12VOLResetassertedReset notasserted20300.40.30.4VV 0.3 ✕ VCCMIN0.71.00.781.245VTHVTH301.530150240200µsnsµsVkΩmsTYPMAX5.55.55.55.51012VTH+ 1.8%VTH+ 3%µAVUNITSSupply CurrentReset ThresholdVTHMAX680_US_ _D_-T,Table 1VCC falling at 10V/msMAX680_US_ _D1-TVVCC Falling Reset DelayReset Active Timeout PeriodMR Minimum Pulse WidthMR Glitch ImmunityMR Reset DelayMR Input VoltageMR Pullup ResistanceRESET Output Low Voltage(MAX6804/MAX6805)RESET Output High Voltage(MAX6804)tRPµsMAX680_US_ _D2-TMAX680_US_ _D3-TVOH2_______________________________________________________________________________________
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4-Pin, Low-Power
µP Reset Circuits with Manual Reset
ELECTRICAL CHARACTERISTICS (continued)
(VCC= full range, TA= -40°C to +125°C, unless otherwise noted. Typical values are at VCC= +5.0V and TA= +25°C, reset not asserted.) (Note 1)PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSISOURC E = 1µA, VCC ≥ 1.0V0.8 ✕ VCCRESET Output VoltageVOHResetassertedISOURC E = 200µA, VCC ≥ 1.8V0.8 ✕ VCCV(MAX6803)ISOURC E = 800µA, VCC ≥ 4.25V 0.8 ✕ VCCVOLReset notISINK = 1.2mA, V CC ≥ 3.0V0.3assertedISINK = 3.2mA, V CC ≥ 5.0V0.4VRESET Output Leakage Current(MAX6805)VCC > VTH, RESET not asserted0.5µANote 1:All parts are production tested at TA= +25°C. Over temperature limits are guaranteed by design and not production tested.Note 2:ISOURCEfor the MAX6803 is 100nA; ISINKfor the MAX6804 is 100nA; ISINKfor the MAX6805 is 50µA.__________________________________________Typical Operating Characteristics
(Reset not asserted, TA= +25°C, unless otherwise noted.)
NORMALIZED RESET TIMEOUT PERIOD
OUTPUT VOLTAGE LOWSUPPLY CURRENT vs. TEMPERATURE
vs. TEMPERATURE
vs. SUPPLY VOLTAGE
6.511.050280
3000ccocoott t 5 5VTH = 2.93V50D00///6.04O1.040400I/SINK = 500µA40I/3R3008E8)6VRESET /308AP1.03066XXmX5.5
M TAAM(60
MU VWCC = +5.0VO1.020EO+125°C)MAI1.010L Eµ5.0T G(T CECS1.000ATL40
+85°CI4.5ERO0.990V+25°C D TU-40°C4.0VCC = +3.3VEZILA0.980PTUMO0.97020
R3.5ON0.9603.00.950
0
-50
-25
0
25
50
75
100
125
-50
-25
0
25
50
75
100
125
1.0
1.5
2.02.5
3.0
TEMPERATURE (°C)
TEMPERATURE (°C)
VCC (V)
OUTPUT VOLTAGE HIGHMAXIMUM TRANSIENT DURATIONVCC FALLING PROPAGATION DELAY
vs. SUPPLY VOLTAGE
vs. RESET COMPARATOR OVERDRIVE
vs. TEMPERATURE
100
4600500100
60cccooo)ttt VVTH = 2.93V5)55000m///44904(Is0 SINK = 100µAµ()H50000///33300088)8ORESET ASSERTED 6N6sV -75
(MAX6803)XOX806AIAµXAMTM( M CACR400YA70VCC = FALLING AT 1V/msVUL(DE H D 60GNI50
+125°CTNHEI 300RESET OCCURSOIEST50GNAAAGTAL+85°CRT P40O200OV+25°CMR TO30U25
UMPIPXTAU100
RESET DOES20OMNOT OCCURV-40°C10CC = FALLING AT 10V/ms00
0
1.0
1.5
2.02.5
3.0
0.1
1101001000
-50-250255075100125
VCC (V)
RESET COMPARATOR OVERDRIVE (mV)
TEMPERATURE (°C)
_______________________________________________________________________________________3
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4-Pin, Low-Power
µP Reset Circuits with Manual ResetMAX6803/MAX6804/MAX6805Pin Description
PINMAX68031MAX6804MAX68051NAMEGNDGroundActive-Low Reset Output. RESETis asserted while VCCis below the resetthreshold, or while MRis asserted. RESETremains asserted for a resettimeout period (tRP) after VCCrises above the reset threshold or MRisdeasserted. RESET on the MAX6804 is push/pull. RESETon the MAX6805is open-drain. Active-High Reset Output. RESET is asserted high while VCCis below thereset threshold or while MRis asserted, and RESET remains asserted for areset timeout period (tRP) after VCCrises above the reset threshold or MRis deasserted. RESETon the MAX6803 is push/pull.Manual Reset Input. A logic low on MRasserts reset. Reset remainsasserted as long as MRis low, and for the reset timeout period (tRP) afterMRgoes high. Leave unconnected or connect to VCCif not used.Supply Voltage InputFUNCTION—2RESET2—RESET3434MRVCCApplications Information
Manual Reset Input
Many µP-based products require manual reset capabil-ity, allowing the operator, a test technician, or externallogic circuitry to initiate a reset. A logic low on MRasserts reset. Reset remains asserted while MRis low,and for the reset active timeout period after MRreturnshigh. MRhas an internal 20kΩpullup resistor, so it canbe left unconnected if not used. Connect a normallyopen momentary switch from MRto GND to create amanual reset function; external debounce circuitry isnot required.
shows the maximum pulse width that a negative-goingVCCtransient may typically have without issuing a resetsignal. As the amplitude of the transient increases, themaximum allowable pulse width decreases.
When VCCfalls below 1V and approaches the minimumoperating voltage of 0.7V, push/pull-structured resetsinking (or sourcing) capabilities decrease drastically.High-impedance CMOS-logic inputs connected to theRESETpin can drift to indeterminate voltages. Thisdoes not present a problem in most cases, since most
VCCVCC100kΩVCCµPMOTOROLA68HCXXRESETEnsuring a Valid Reset Output
down to VCC = 0
Interfacing to µPs withBidirectional Reset Pins
Since the RESEToutput on the MAX6805 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 singlepullup resistor allows either device to assert reset(Figure 1).
In addition to issuing a reset to the µP during power-up,power-down, and brownout conditions, these devicesare relatively immune to short-duration, negative-goingVCCtransients (glitches). TheTypical OperatingCharacteristicsshow the Maximum Transient Durationvs. Reset Comparator Overdrive graph. The graph
4
MAX6805MRRESETNegative-Going VCCTransients
GNDGNDFigure 1. Interfacing to µPs with Bidirectional Reset Pins
_______________________________________________________________________________________
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4-Pin, Low-Power
µP Reset Circuits with Manual Reset
µPs and circuitry do not operate when VCCdrops belowSince the MAX6805 has an open-drain, active-low out-1V. For the MAX6804 application where RESETmust beput, it typically uses a pullup resistor. With this device,valid down to 0, adding a pulldown resistor betweenRESETwill most likely not maintain an active condition,RESETand GND removes stray leakage currents, hold-but will drift to a non-active level due to the pulluping RESETlow (Figure 2a). The pulldown resistor valueresistor and the reduced sinking capability of the open-is not critical; 100kΩis large enough not to load RESET,drain device. Therefore, this device is not recommend-and small enough to pull it low. For the MAX6803, whereed for applications where the RESETpin is required toRESET must be valid to VCC= 0, a 100kΩpullup resistorbe valid down to Vbetween RESET and VCCwill hold RESET high whenCC= 0.
VCCfalls below 0.7V (Figure 2b).
VPin ConfigurationCCTOP VIEWMAX6804MRRESETGND14VCC(a)GND100kΩMAX6803MAX6804MAX6805VCCRESET(RESET)23MR100kΩ*MAX6803SOT143( ) ARE FOR MAX6803MRRESET(b)GND*ASSUMES HIGH-Z RESET INPUT TO THE µPTypical Operating CircuitFigure 2. Ensuring Reset Valid down to VCC= 0
VCCVCCVCCMAX6804µPMRRESETRESETGNDGNDPUSHBUTTONSWITCH_______________________________________________________________________________________5
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4-Pin, Low-Power
µP Reset Circuits with Manual ResetMAX6803/MAX6804/MAX6805Table 1. Factory-Trimmed Reset Thresholds
RESETTHRESHOLDSUFFIX48474544434241403938373635343332313029282726TA = +25°CMIN4.7144.6154.5474.4194.3014.2234.1244.0263.9284.8303.7323.6333.5353.4373.3393.2413.1423.0252.9462.8772.7502.6512.583TYP (VTH)4.804.704.634.504.384.304.204.104.003.903.803.703.603.503.403.303.203.083.002.932.802.702.63MAX4.88.7854.7134.5814.4594.3774.27.1744.0723.9703.8683.7673.6653.5633.4613.3593.2583.1353.0542.9832.8502.7492.677MIN4.65.5594.4914.3654.2494.1714.0743.9773.8803.7833.6863.53.4923.3953.2983.2013.1042.9882.9102.8422.7162.6192.551TA = -40°C to +125°CMAX4.9444.8414.7694.6354.5114.4294.32.2234.1204.0173.9143.8113.7083.6053.5023.3993.2963.1723.0903.0182.8842.7812.7096_______________________________________________________________________________________
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4-Pin, Low-Power
µP Reset Circuits with Manual Reset
Selector Guide (Standard Versions*)
PARTOUTPUT STAGENOMINAL VTH (V)MIN RESETSOTTIMEOUT (ms)TOP MARKMAX6803US26D3-TPush/Pull RESET2.63100KACHMAX6803US29D3-TPush/Pull RESET2.93100KACIMAX6803US31D3-TPush/Pull RESET3.08100KACJMAX6803US44D3-TPush/Pull RESET4.38100KACKMAX6803US46D3-TPush/Pull RESET4.63100KACLMAX6804US26D3-TPush/Pull RESET2.63100KACNMAX6804US29D3-TPush/Pull RESET2.93100KACPMAX6804US31D3-TPush/Pull RESET3.08100KACQMAX6804US44D3-TPush/Pull RESET4.38100KACRMAX6804US46D3-TPush/Pull RESET4.63100KACSMAX6805US26D3-TOpen-Drain RESET2.63100KACOMAX6805US29D3-TOpen-Drain RESET2.93100KACUMAX6805US31D3-TOpen-Drain RESET3.08100KACVMAX6805US44D3-TOpen-Drain RESET4.38100KACWMAX6805US46D3-TOpen-Drain RESET4.63100KACX*Sample stock is generally held on all standard versions.Chip InformationTRANSISTOR COUNT:505PROCESS: BiCMOS
_______________________________________________________________________________________7
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4-Pin, Low-Power
µP Reset Circuits with Manual ResetMAX6803/MAX6804/MAX6805Package Information
SOT1434.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.
8_____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600©2001 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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