Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - system monitor Reset/power-on reset SC 70 4

General Description

The MAX6340/MAX6421–MAX6426 low-power micropro-

cessor supervisor circuits monitor system voltages from

1.6V to 5V. These devices perform a single function: they

assert a reset signal whenever the V

supply 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, push-

pull 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

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

Note: The MAX6340/MAX6421–MAX6426 are available with

factory-trimmed reset thresholds from 1.575V to 5.0V in approxi-

mately 0.1V increments. Insert the desired nominal reset thresh-

old 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.

Devices are available in both leaded and lead-free packaging.

Specify lead-free by replacing “-T” with “+T” when ordering.

PART TEMP RANGE PIN-PACKAGE

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

MAX6340UK_ _/V-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

GND

( ) ARE FOR THE MAX6422

1 4

SRT

MAX6421X

MAX6422X

MAX6423X

SC70

TOP VIEW

RESET

(RESET)

MAX6340/MAX6421–

MAX6426

Low-Power, SC70/SOT µP Reset Circuits

with Capacitor-Adjustable Reset Timeout Delay

19-2440; Rev 5; 3/14

Selector Guide appears at end of data sheet.

Ordering Information

Pin Configurations continued at end of data sheet.

Pin Congurations

Typical Operating Circuit appears at end of data sheet.

Summary of content (9 pages)

PAGE 1
MAX6340/MAX6421– MAX6426 Low-Power, SC70/SOT µP Reset Circuits with Capacitor-Adjustable Reset Timeout Delay 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 VCC supply voltage falls below its reset threshold. The reset output remains asserted for the reset timeout period after VCC rises above the reset threshold.
PAGE 2
MAX6340/MAX6421– MAX6426 Low-Power, SC70/SOT µP Reset Circuits with Capacitor-Adjustable Reset Timeout Delay Absolute Maximum Ratings All Voltages Referenced to GND VCC........................................................................-0.3V to +6.0V SRT, RESET, RESET (push-pull).............. -0.3V to (VCC + 0.3V) RESET (open drain)..............................................-0.3V to +6.0V Input Current (all pins).......................................................
PAGE 3
MAX6340/MAX6421– MAX6426 Low-Power, SC70/SOT µP Reset Circuits with Capacitor-Adjustable Reset Timeout Delay Typical Operating Characteristics (VCC = 5V, CSRT = 1500pF, TA = +25°C, unless otherwise noted.) 2.0 TA = -40°C 1.5 1.0 0.5 0 0 1 2 3 4 5 100 10 1 0.1 0.001 6 0.
PAGE 4
MAX6340/MAX6421– MAX6426 Low-Power, SC70/SOT µP Reset Circuits with Capacitor-Adjustable Reset Timeout Delay Pin Description PIN MAX6340 SOT23 MAX6421 MAX6422 MAX6423 SOT143 SC70 MAX6424 MAX6425 MAX6426 SOT23 SOT23 NAME FUNCTION 1 3 3 5 1 SRT Set Reset Timeout Input. Connect a capacitor between SRT and ground to set the timeout period. Determine the period as follows: tRP = 2.73 × 106 × CSRT + 275µs with tRP in seconds and CSRT in farads 2 1 2 3 2, 3 GND Ground 3 — — 4 — N.C.
PAGE 5
MAX6340/MAX6421– MAX6426 Low-Power, SC70/SOT µP Reset Circuits with Capacitor-Adjustable Reset Timeout Delay CSRT = (tRP - 275µs) / (2.73 5 106) where tRP is in seconds and CSRT is in farads. The reset delay time is set by a current/capacitor-controlled ramp compared to an internal 0.65V reference. An internal 240nA ramp current source charges the external capacitor. The charge to the capacitor is cleared when a reset condition is detected.
PAGE 6
MAX6340/MAX6421– MAX6426 Low-Power, SC70/SOT µP Reset Circuits with Capacitor-Adjustable Reset Timeout Delay Table 1. Reset Threshold Voltage Suffix VCC SUFFIX MIN TYP MAX 16 1.536 1.575 1.614 17 1.623 1.665 1.707 18 1.755 1.800 1.845 19 1.853 1.900 1.948 20 1.950 2.000 2.050 21 2.048 2.100 2.153 22 2.133 2.188 2.243 23 2.313 2.313 2.371 24 2.340 2.400 2.460 25 2.438 2.500 2.563 26 2.559 2.625 2.691 27 2.633 2.700 2.768 28 2.730 2.800 2.870 29 2.
PAGE 7
MAX6340/MAX6421– MAX6426 Low-Power, SC70/SOT µP Reset Circuits with Capacitor-Adjustable Reset Timeout Delay Standard Versions Table PART* OUTPUT STAGE TOP MARK PART* OUTPUT STAGE TOP MARK MAX6340UK16-T Open-Drain RESET AEBE MAX6423US16-T Open-Drain RESET KADC MAX6340UK22-T Open-Drain RESET AEBG MAX6423XS16-T Open-Drain RESET ACW MAX6340UK26-T Open-Drain RESET AEBI MAX6423US22-T Open-Drain RESET KADU MAX6340UK29-T Open-Drain RESET AEBJ MAX6423XS22-T Open-Drain RESET ADO MAX63
PAGE 8
MAX6340/MAX6421– MAX6426 Low-Power, SC70/SOT µP Reset Circuits with Capacitor-Adjustable Reset Timeout Delay Pin Configurations (continued) TOP VIEW SRT 1 GND 2 5 RESET RESET MAX6340 N.C. 3 1 VCC 2 4 VCC SRT 4 N.C.
PAGE 9
MAX6340/MAX6421– MAX6426 Low-Power, SC70/SOT µP Reset Circuits with Capacitor-Adjustable Reset Timeout Delay Revision History REVISION NUMBER REVISION DATE 5 3/14 DESCRIPTION Added /V OPN to Ordering Information PAGES CHANGED 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.