MAX6387XS26D7-T中文资料

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19-1839; Rev 1; 04/01

SC70, Single/Dual Low-Voltage, Low-Power µP Reset Circuits

General Description

Features

The MAX6381–MAX6390 microprocessor (µP) supervisorycircuits monitor power supply voltages from +1.8V tooFactory-Set Reset Threshold Voltages Ranging+5.0V while consuming only 3µA of supply current atfrom +1.58V to +4.63V in Approximately 100mV+1.8V. Whenever VCCfalls below the factory-set resetIncrementsthresholds, the reset output asserts and remains assert-o±2.5% Reset Threshold Accuracy Overed for a minimum reset timeout period after VCCrisesTemperature (-40°C to +125°C)above the reset threshold. Reset thresholds are availablefrom +1.58V to +4.63V, in approximately 100mV incre-oSeven Reset Timeout Periods Available: 1ms,ments. Seven minimum reset timeout delays ranging20ms, 140ms, 280ms, 560ms, 1120ms, from 1ms to 1200ms are available.

1200ms (min)The MAX6381/MAX6384/MAX6387 have a push-pullo3 Reset Output Options

active-low reset output. The MAX6382/MAX6385/Active-Low Push-PullMAX6388 have a push-pull active-high reset output,Active-High Push-Pulland the MAX6383/MAX6386/MAX6389/MAX6390 have an open-drain active-low reset output. TheActive-Low Open-Drain

MAX6384/MAX6385/MAX6386 also feature aoReset Output State Guaranteed Valid debounced manual reset input (with internal pullupDown to VCC= 1V

resistor). The MAX6387/MAX6388/MAX6389 have anauxiliary input for monitoring a second voltage. TheoManual Reset Input (MAX6384/MAX6385/MAX6386)MAX6390 offers a manual reset input with a longer VoAuxiliary RESETIN

reset timeout period (1120ms or 1200ms) and a shorterCC(MAX6387/MAX6388/MAX6389)

manual reset timeout (140ms or 150ms).

oVCCReset Timeout (1120ms or 1200ms)/ManualThe MAX6381/MAX6382/MAX6383 are available in 3-pinReset Timeout (140ms or 150ms) (MAX6390)SC70 packages and the MAX6384–MAX6390 are avail-able in 4-pin SC70 packages.

oNegative-Going VCCTransient Immunity________________________Applications

oLow Power Consumption of 6µA at +3.6V and 3µA at +1.8VComputersoPin Compatible with

Controllers

MAX809/MAX810/MAX803/MAX6326/MAX6327/Intelligent Instruments

MAX6328/MAX6346/MAX6347/MAX6348, Critical µP and µC Power Monitoringand MAX6711/MAX6712/MAX6713Portable/Battery-Powered EquipmentoTiny 3-Pin SC70 and 4-Pin SC70 Packages

Dual Voltage Systems

Pin Configurations

Note:Insert reset threshold suffix (see Reset Threshold table)after "XR" or "XS". Insert reset timeout delay (see Reset TimeoutDelay table) after "D" to complete the part number. Samplestock is generally held on standard versions only (see

Standard Versions table). Standard versions have an orderincrement requirement of 2500 pieces. Nonstandard versionshave an order increment requirement of 10,000 pieces.Contact factory for availability of nonstandard versions.*MAX6390 is available with D4 or D7 timing only.

Ordering Information continuedat end of data sheet.

Typical Operating Circuit appears at end of data sheet.Selector Guide appears at end of data sheet.

________________________________________________________________Maxim Integrated Products

1

For pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at .

MAX6381–MAX6390

SC70, Single/Dual Low-Voltage, Low-Power µP Reset Circuits

MAX6381–MAX6390

ABSOLUTE MAXIMUM RATINGS

VCC to GND..........................................................-0.3V to +6.0VRESETOpen-Drain Output....................................-0.3V to +6.0VRESET, RESET (Push-Pull Output).............-0.3V to (VCC+ 0.3V)MR, RESET IN.............................................-0.3V to (VCC+ 0.3V)Input Current (VCC).............................................................20mAOutput Current (All Pins).....................................................20mA

Continuous Power Dissipation (TA= +70°C)

3-Pin SC70 (derate 2.9mW/°C above +70°C)........235mW4-Pin SC70 (derate 3.1mW/°C above +70°C)........245mWOperating Temperature Range.........................-40°C to +125°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

SC70, Single/Dual Low-Voltage, Low-Power µP Reset Circuits

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MAX6381–MAX6390

SC70, Single/Dual Low-Voltage, Low-Power µP Reset CircuitsMAX6381–MAX6390

Typical Operating Characteristics

(TA = +25°C, unless otherwise noted.)

SUPPLY CURRENT vs. TEMPERATURE

(NO LOAD)

POWER-DOWN RESET DELAY

vs. TEMPERATURE

NORMALIZED RESET TIMEOUT PERIOD

8SUPPLY CURRENT (µA)

76543210

41POWER-DOWN RESET DELAY (µs)

39373533312927

1.061.041.021.000.980.960.94

-40-25-105203550658095110125

TEMPERATURE (°C)

25

-40-25-10520

3550658095110125

TEMPERATURE (°C)

-40-25-105203550658095110125

TEMPERATURE (°C)

NORMALIZED RESET THRESHOLD

vs. TEMPERATURE

MAX6381/90 toc04

OUTPUT VOLTAGE LOWvs. SINK CURRENT

OUTPUT VOLTAGE HIGHvs. SOURCE CURRENT

1.020NORMALIZED RESET

THRESHOLD1.0151.0101.0051.0000.9950.9900.985

1.21.00.8VOL (V)

0.6

0.40.200

3

6ISINK (mA)

93.02.52.0VOH (V)

1.51.00.500

250

500

750

1000

1250

0.990

-40-25-105203550658095110125

TEMPERATURE (°C)

12

1500

ISOURCE (µA)

MAXIMUM TRANSIENT DURATIONvs. RESET COMPARATOR OVERDRIVE

RESET IN TO RESET DELAY

vs. TEMPERATURE

5.35.1RESET IN DELAY (µs)

4.94.74.54.34.13.93.73.5

MAX6381/90 toc08

500MAXIMUM TRANSIENT DURATION (µs)

45040035030025020015010050

1

10

100

5.5

1000-40-25-105203550658095110125

TEMPERATURE (°C)

RESET COMPARATOR OVERDRIVE, VTH - VCC (mV)

4______________________________________________________________________________________

MAX6381/90 toc03

9

NORMALIZED POWER-UP RESET TIMEOUT

vs. TEMPERATURE

1.08

43

SC70, Single/Dual Low-Voltage, Low-Power µP Reset Circuits

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MAX6381–MAX6390

SC70, Single/Dual Low-Voltage, Low-Power µP Reset CircuitsMAX6381–MAX6390

Detailed Description

RESET Output

A µP reset input starts the µP in a known state. TheseµP supervisory circuits assert reset to prevent codeexecution errors during power-up, power-down, orbrownout conditions.

Reset asserts when VCCis below the reset threshold;once VCCexceeds the reset threshold, an internal timerkeeps the reset output asserted for the reset timeoutperiod. After this interval, reset output deasserts. Resetoutput is guaranteed to be in the correct logic state forVCC≥1V.

Manual Reset Input (MAX6384/MAX6385/MAX6386/MAX6390)

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 (tRP) after MRreturns high. This input has an internal 63k pullupresistor (1.35k for MAX6390), so it can be left uncon-nected if it is not used. MRcan be driven with TTL orCMOS logic levels, or with open-drain/collector outputs.Connect a normally open momentary switch from MRtoGND to create a manual-reset function; externaldebounce circuitry is not required. If MRis driven fromlong cables or if the device is used in a noisy environ-ment, connecting a 0.1µF capacitor from MRto GNDprovides additional noise immunity.

RESET IN Comparator

(MAX6387/MAX6388/MAX6389)

RESET IN is compared to an internal +1.27V reference.If the voltage at RESET IN is less than 1.27V, resetasserts. Use the RESET IN comparator as a user-adjustable reset detector or as a secondary power-sup-ply monitor by implementing a resistor-divider at RESETIN (shown in Figure 1). Reset asserts when either VCCor RESET IN falls below its respective threshold volt-age. Use the following equation to set the threshold:

VINTH= VTHRST (R1/R2 + 1)where VTHRST= +1.27V. To simplify the resistor selec-tion, choose a value of R2 and calculate R1:

R1 = R2 [(VINTH/VTHRST) - 1]

Since the input current at RESET IN is 50nA (max),large values can be used for R2 with no significant lossin accuracy.

___________Applications Information

In addition to issuing a reset to the µP during power-up,power-down, and brownout conditions, theMAX6381–MAX6390 are relatively immune to short dura-tion negative-going VCCtransients (glitches).

The Typical Operating Characteristicssection shows theMaximum Transient Durations vs. Reset ComparatorOverdrive, for which the MAX6381–MAX6390 do notgenerate a reset pulse. This graph was generated using

Negative-Going VCCTransients

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SC70, Single/Dual Low-Voltage, Low-Power µP Reset Circuits

MAX6381–MAX6390

not work with the open-drain outputs of theMAX6383/MAX6386/MAX6389/MAX6390. The resistorvalue used is not critical, but it must be small enoughnot to load the reset output when VCCis above the resetthreshold. For most applications, 100k is adequate.

a negative-going pulse applied to VCC, starting above theactual reset threshold and ending below it by the magni-tude indicated (reset comparator overdrive). The graphindicates the typical maximum pulse width a negative-going VCCtransient may have without causing a resetpulse to be issued. As the magnitude of the transientincreases (goes farther below the reset threshold), themaximum allowable pulse width decreases. A 0.1µFcapacitor mounted as close as possible to VCCprovidesadditional transient immunity.

The MAX6381–MAX6390 are guaranteed to operateproperly down to VCC= 1V. In applications that requirevalid reset levels down to VCC= 0, a pulldown resistor toactive-low outputs (push/pull only, Figure 2) and apullup resistor to active-high outputs (push/pull only) willensure that the reset line is valid while the reset outputcan no longer sink or source current. This scheme does

Ensuring a Valid RESETOutput Down to VCC= 0

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SC70, Single/Dual Low-Voltage, Low-Power µP Reset CircuitsMAX6381–MAX6390

Pin Configurations (continued)

*MRis for MAX6384/MAX6385/MAX6386/MAX6390**RESET IN is for MAX6387/MAX6388/MAX6389( ) are for MAX6382/MAX6385/MAX6388

Chip Information

TRANSISTOR COUNT: 647PROCESS: BiCMOS

8

SC70, Single/Dual Low-Voltage, Low-Power µP Reset Circuits

Ordering Information

Note:Insert reset threshold suffix (see Reset Threshold table)after "XR" or "XS". Insert reset timeout delay (see Reset TimeoutDelay table) after "D" to complete the part number. Samplestock is generally held on standard versions only (see

Standard Versions table). Standard versions have an orderincrement requirement of 2500 pieces. Nonstandard versionshave an order increment requirement of 10,000 pieces.Contact factory for availability of nonstandard versions.*MAX6390 is available with D4 or D7 timing only.

_______________________________________________________________________________________9

MAX6381–MAX6390

SC70, Single/Dual Low-Voltage, Low-Power µP Reset CircuitsMAX6381–MAX6390

Package Information

10______________________________________________________________________________________

SC70, Single/Dual Low-Voltage, Low-Power µP Reset Circuits

Package Information (continued)

Maxim 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.

Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600____________________11©2001 Maxim Integrated Products

Printed USA

is a registered trademark of Maxim Integrated Products.

MAX6381–MAX6390

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