MAXIM MAX6340, MAX6421 Technical data

General Description

The MAX6340/MAX6421–MAX6426 low-power microprocessor supervisor circuits monitor system voltages from 1.6V to 5V. These devices perform a single function: they assert a reset signal whenever the VCCsupply voltage falls below its reset threshold. The reset output remains asserted for the reset timeout period after V

rises above the reset threshold. The reset timeout is externally set by a capacitor to provide more flexibility.

The MAX6421/MAX6424 have an active-low, pushpull reset output. The MAX6422 has an active-high, push-pull reset output and the MAX6340/MAX6423/ MAX6425/MAX6426 have an active-low, open-drain reset output. The MAX6421/MAX6422/MAX6423 are offered in 4-pin SC70 or SOT143 packages. The MAX6340/MAX6424/MAX6425/MAX6426 are available in 5-pin SOT23-5 packages.

Applications

Portable Equipment

Battery-Powered Computers/Controllers

Automotive

Medical Equipment

Intelligent Instruments

Embedded Controllers

Critical µP Monitoring

Set-Top Boxes

Computers

Features

♦ Monitor System Voltages from 1.6V to 5V

♦ Capacitor-Adjustable Reset Timeout Period

♦ Low Quiescent Current (1.6µA typ)

♦ Three RESET Output Options

Push-Pull RESET Push-Pull RESET Open-Drain RESET

♦ Guaranteed Reset Valid to V

= 1V

♦ Immune to Short V

Transients

♦ Small 4-Pin SC70, 4-Pin SOT143, and 5-Pin SOT23

Packages

♦ MAX6340 Pin Compatible with LP3470

♦ MAX6424/MAX6425 Pin Compatible with

NCP300–NCP303, MC33464/MC33465, S807/S808/S809, and RN5VD

♦ MAX6426 Pin Compatible with PST92XX

MAX6340/MAX6421–MAX6426

Low-Power, SC70/SOT µP Reset Circuits with

Capacitor-Adjustable Reset Timeout Delay

________________________________________________________________ Maxim Integrated Products 1

Ordering Information

GND

( ) ARE FOR THE MAX6422

SRT

MAX6421X MAX6422X MAX6423X

SC70

TOP VIEW

RESET (RESET)

Pin Configurations

19-2440; Rev 2; 10/02

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

Typical Operating Circuit appears at end of data sheet.

Selector Guide appears at end of data sheet.

Note: The MAX6340/MAX6421–MAX6426 are available with fac-

tory-trimmed reset thresholds from 1.575V to 5.0V in approximately 0.1V increments. Insert the desired nominal reset threshold suffix (from Table 1) into the blanks. There are 50 standard versions with a required order increment of 2500 pieces. Sample stock is generally held on standard versions only (see Standard Versions Table). Required order increment is 10,000 pieces for nonstandard versions. Contact factory for availability. All devices are available in tape-and-reel only.

Pin Configurations continued at end of data sheet.

查询MAX6340供应商

PART TEMP RANGE PIN-PACKAGE

MAX6340UK_ _-T -40°C to +125°C 5 SOT23-5

MAX6421XS_ _-T -40°C to +125°C 4 SC70-4

MAX6421US_ _-T -40°C to +125°C 4 SOT143-4

MAX6422XS_ _-T -40°C to +125°C 4 SC70-4

MAX6422US_ _-T -40°C to +125°C 4 SOT143-4

MAX6423XS_ _-T -40°C to +125°C 4 SC70-4

MAX6423US_ _-T -40°C to +125°C 4 SOT143-4

MAX6424UK_ _-T -40°C to +125°C 5 SOT23-5

MAX6425UK_ _-T -40°C to +125°C 5 SOT23-5

MAX6426UK_ _-T -40°C to +125°C 5 SOT23-5

MAX6340/MAX6421–MAX6426

Low-Power, SC70/SOT µP Reset Circuits with Capacitor-Adjustable Reset Timeout Delay

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= 1V to 5.5V, TA= T

MIN

to T

MAX

, unless otherwise specified. Typical values are at VCC= 5V and TA= +25°C.) (Note 1)

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

All Voltages Referenced to GND

VCC........................................................................-0.3V to +6.0V

SRT, RESET, RESET (push-pull).................-0.3V to (V

+ 0.3V)

RESET (open drain)...............................................-0.3V to +6.0V

Input Current (all pins)......................................................±20mA

Output Current (RESET, RESET) ......................................±20mA

Continuous Power Dissipation (T

= +70°C)

4-Pin SC70 (derate 3.1mW/°C above +70°C)..............245mW

4-Pin SOT143 (derate 4mW/°C above +70°C).............320mW

5-Pin SOT23 (derate 7.1mW/°C above +70°C)............571mW

Operating Temperature Range .........................-40°C to +125°C

Storage Temperature Range .............................-65°C to +150°C

Junction Temperature......................................................+150°C

Lead Temperature (soldering, 10s) .................................+300°C

Note 1: Devices production tested at +25°C. Overtemperature limits are guaranteed by design.

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Supply Voltage Range V

VCC Reset Threshold Accuracy V

Hysteresis V

VCC to Reset Delay t

Reset Timeout Period t

Ramp Current I

SRT

Ramp Threshold V

SRT

RAMP Threshold Hysteresis V

RESET Output Voltage High, Push-Pull

RESET Output Leakage Current, Open-Drain

RESET Output Voltage High V

RESET Output Voltage Low V

VCC ≤ 5.0V 2.5 4.2

VCC ≤ 3.3V 1.9 3.4Supply Current I

VCC ≤ 2.0V 1.6 2.5

HYST

RAMP

TH-RAMPVCC

TA = +25°CV

TA = -40°C to +125°CV

VCC falling at 1mV/µs 80 µs

= 1500pF 3.00 4.375 5.75

SRT

= 0 0.275

SRT

= 0 to 0.65V; VCC = 1.6V to 5V 240 nA

SRT

= 1.6V to 5V (V

falling threshold 33 mV

RAMP

VCC ≥ 1.0V, I

VCC ≥ 2.7V, I

VCC ≥ 4.5V, I

VCC ≥ 1.8V, I

VCC ≥ 2.25V, I

VCC ≥ 4.5V, I

LKG

VCC > VTH, reset not asserted 1.0 µA

VCC ≥ 1.0V, I

VCC ≥ 1.8V, I

VCC ≥ 2.7V, I

VCC ≥ 4.5V, I

VCC ≥ 1.8V, I

VCC ≥ 2.7V, I

VCC ≥ 4.5V, I

1.0 5.5 V

- 1.5% VTH + 1.5%

- 2.5% VTH + 2.5%

4 x V

rising) 0.65 V

RAMP

= 50µA 0.3

SINK

= 1.2mA 0.3RESET Output Voltage Low V

SINK

= 3.2mA 0.4

SINK

= 200µA 0.8 x V

SOURCE

= 500µA 0.8 x V

SOURCE

= 800µA 0.8 x V

SOURCE

= 1µA 0.8 x V

SOURCE

= 150µA 0.8 x V

SOURCE

= 500µA 0.8 x V

SOURCE

= 800µA 0.8 x V

SOURCE

= 500µA 0.3

SINK

= 1.2mA 0.3

SINK

= 3.2mA 0.4

SINK

µA

MAX6340/MAX6421–MAX6426

Low-Power, SC70/SOT µP Reset Circuits with

Capacitor-Adjustable Reset Timeout Delay

_______________________________________________________________________________________ 3

Typical Operating Characteristics

(VCC= 5V, C

SRT

= 1500pF, TA = +25°C, unless otherwise noted.)

4.0

3.5

3.0

2.5

2.0

1.5

SUPPLY CURRENT (µA)

1.0

0.5

021 3456

600

550

500

450

400

350

300

RESET TIMEOUT PERIOD (µs)

250

200

-50 0 25-25

SUPPLY CURRENT

vs. SUPPLY VOLTAGE

10,000

TA = +125°C

TA = +25°C

TA = -40°C

SUPPLY VOLTAGE (V)

1000

MAX6421/26 toc01

100

RESET TIMEOUT PERIOD (ms)

0.1

0.001 0.10.01 1 10

RESET TIMEOUT PERIOD

vs. TEMPERATURE

TEMPERATURE (°C)

= 0

SRT

75 100 125

MAX6421/26 toc04

vs. RESET THRESHOLD OVERDRIVE

175

150

125

100

TRANSIENT DURATION (µs)

0 400200 600 800 1000

RESET TIMEOUT PERIOD vs. C

(nF)

SRT

MAXIMUM TRANSIENT DURATION

RESET OCCURS ABOVE THE CURVE

RESET THRESHOLD OVERDRIVE (mV)

SRT

100

VTH = 2.95V

4.30

MAX6421/26 toc02

4.25

4.20

4.15

RESET TIMEOUT PERIOD (ms)

MAX6421/26 toc05

4.10

160

150

140

130

120

110

TO RESET DELAY (µs)

100

1000

RESET TIMEOUT PERIOD

vs. TEMPERATURE

= 1500pF

SRT

-50 0-25 25 50 75 100 125 TEMPERATURE (°C)

VCC TO RESET DELAY

vs. TEMPERATURE (V

VCC FALLING AT 1mVµs

-50 0 25-25 TEMPERATURE (°C)

FALLING)

75 100 125

MAX6421/26 toc03

MAX6421/26 toc06

1V/div

POWER-UP/POWER-DOWN

CHARACTERISTIC

RESET

400µs/div

VTH = 1.6V

MAX6421/26 toc07

NORMALIZED RESET THRESHOLD

vs. TEMPERATURE

1.006

1.004

1.002

1.000

0.998

0.996

0.994

-50 25 50-25 0 75 100 125 TEMPERATURE (°C)

MAX6421/26 toc08

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