General Description
The MAX6746–MAX6753 low-power microprocessor
(μP) supervisory circuits monitor single/dual system
supply voltages from 1.575V to 5V and provide maxi-
mum adjustability for reset and watchdog functions.
These devices assert a reset signal whenever the V
CC
supply voltage or RESET IN falls below its reset thresh-
old or when manual reset is pulled low. The reset output
remains asserted for the reset timeout period after V
CC
and RESET IN rise above the reset threshold. The reset
function features immunity to power-supply transients.
The MAX6746–MAX6753 have ±2% factory-trimmed
reset threshold voltages in approximately 100mV incre-
ments from 1.575V to 5.0V and/or adjustable reset
threshold voltages using external resistors.
The reset and watchdog delays are adjustable with
external capacitors. The MAX6746–MAX6751 contain a
watchdog select input that extends the watchdog time-
out period by 128x. The MAX6752/MAX6753 contain a
window watchdog timer that looks for activity outside an
expected window of operation.
The MAX6746–MAX6753 are available with a push-pull
or open-drain active-low
RESET
output. The MAX6746–
MAX6753 are available in an 8-pin SOT23 package and
are fully specified over the automotive temperature
range (-40°C to +125°C).
Applications
Features
o
Factory-Set Reset Threshold Options from 1.575V
to 5V in ~100mV Increments
o
Adjustable Reset Threshold Options
o
Single/Dual Voltage Monitoring
o
Capacitor-Adjustable Reset Timeout
o
Capacitor-Adjustable Watchdog Timeout
o
Min/Max (Windowed) Watchdog Option
o
Manual Reset Input Option
o
Guaranteed
RESET
Valid for V
CC
≥
1V
o
3.7μA Supply Current
o
Push-Pull or Open-Drain
RESET
Output Options
o
Power-Supply Transient Immunity
o
Small 8-Pin SOT23 Packages
M
μP Reset Circuits with Capacitor-Adjustable
Reset/Watchdog Timeout Delay
________________________________________________________________
Maxim Integrated Products
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.
1
WDI
WDS
GND
1
2
8
7
V
CC
RESET
SWT
SRT
RESET IN (MR)
( ) ARE FOR MAX6746 AND MAX6747 ONLY.
TOP VIEW
3
4
6
5
MAX6746–
MAX6751
SOT23-8
Pin Configurations
19-2530; Rev 2; 8/03
Note:
“_ _” represents the two number suffix needed when
ordering the reset threshold voltage value for the
MAX6746/MAX6747 and MAX6750–MAX6753. The reset
threshold voltages are available in approximately 100mV incre-
ments. Table 2 contains the suffix and reset factory-trimmed
voltages. All devices are available in tape-and-reel only. There
is a 2500-piece minimum order increment for standard ver-
sions (see Table 3). Sample stock is typically held on standard
versions only. Nonstandard versions require a minimum order
increment of 10,000 pieces. Contact factory for availability.
Medical Equipment
Automotive
Intelligent Instruments
Portable Equipment
Battery-Powered
Computers/Controllers
Embedded Controllers
Critical μP Monitoring
Set-Top Boxes
Computers
Ordering Information
PART
TEMP RANGE
-40
°
C to +125
°
C
-40
°
C to +125
°
C
-40
°
C to +125
°
C
-40
°
C to +125
°
C
-40
°
C to +125
°
C
-40
°
C to +125
°
C
-40
°
C to +125
°
C
-40
°
C to +125
°
C
PIN-PACKAGE
8 SOT23-8
8 SOT23-8
8 SOT23-8
8 SOT23-8
8 SOT23-8
8 SOT23-8
8 SOT23-8
8 SOT23-8
MAX6746
KA_ _-T
MAX6747
KA_ _-T
MAX6748
KA-T
MAX6749
KA-T
MAX6750
KA_ _-T
MAX6751
KA_ _-T
MAX6752
KA_ _-T
MAX6753
KA_ _-T
Selector Guide appears at end of data sheet.
Typical Operating Circuit appears at end of data sheet.
Pin Configurations continued at end of data sheet.