19-2440; Rev 2; 10/02
Low-Power, SC70/SOT 碌P Reset Circuits with
Capacitor-Adjustable Reset Timeout Delay
General Description
The MAX6340/MAX6421鈥揗AX6426 low-power micro-
processor supervisor circuits monitor system voltages
from 1.6V to 5V. These devices perform a single function:
they assert a reset signal whenever the V
CC
supply volt-
age falls below its reset threshold. The reset output
remains asserted for the reset timeout period after V
CC
rises above the reset threshold. The reset timeout is exter-
nally 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.
Features
o
Monitor System Voltages from 1.6V to 5V
o
Capacitor-Adjustable Reset Timeout Period
o
Low Quiescent Current (1.6碌A typ)
o
Three RESET Output Options
Push-Pull
RESET
Push-Pull RESET
Open-Drain
RESET
o
Guaranteed Reset Valid to V
CC
= 1V
o
Immune to Short V
CC
Transients
o
Small 4-Pin SC70, 4-Pin SOT143, and 5-Pin SOT23
Packages
o
MAX6340 Pin Compatible with LP3470
o
MAX6424/MAX6425 Pin Compatible with
NCP300鈥揘CP303, MC33464/MC33465,
S807/S808/S809, and RN5VD
o
MAX6426 Pin Compatible with PST92XX
MAX6340/MAX6421鈥揗AX6426
Applications
Portable Equipment
Battery-Powered Computers/Controllers
Automotive
Medical Equipment
Intelligent Instruments
Embedded Controllers
Critical 碌P Monitoring
Set-Top Boxes
Computers
Ordering Information
PART
MAX6340UK_
_-T
MAX6421XS_
_-T
MAX6421US_ _-T
MAX6422XS_
_-T
MAX6422US_ _-T
MAX6423XS_
_-T
MAX6423US_ _-T
MAX6424UK_
_-T
MAX6425UK_
_-T
TEMP RANGE
-40掳C to +125掳C
-40掳C to +125掳C
-40掳C to +125掳C
-40掳C to +125掳C
-40掳C to +125掳C
-40掳C to +125掳C
-40掳C to +125掳C
-40掳C to +125掳C
-40掳C to +125掳C
-40掳C to +125掳C
PIN-PACKAGE
5 SOT23-5
4 SC70-4
4 SOT143-4
4 SC70-4
4 SOT143-4
4 SC70-4
4 SOT143-4
5 SOT23-5
5 SOT23-5
5 SOT23-5
Pin Configurations
TOP VIEW
V
CC
1
4
RESET
(RESET)
MAX6426UK_
_-T
MAX6421X
MAX6422X
MAX6423X
GND
2
3
SRT
Note:
The MAX6340/MAX6421鈥揗AX6426 are available with fac-
tory-trimmed reset thresholds from 1.575V to 5.0V in approxi-
mately 0.1V increments. Insert the desired nominal reset
threshold suffix (from Table 1) into the blanks. There are 50 stan-
dard 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.
Typical Operating Circuit appears at end of data sheet.
Selector Guide appears at end of data sheet.
1
SC70
( ) ARE FOR THE MAX6422
Pin Configurations continued at end of data sheet.
________________________________________________________________
Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim鈥檚 website at www.maxim-ic.com.
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