19-0243; Rev 1; 9/94
3.0V/3.3V Microprocessor Supervisory Circuits
_______________General Description
These microprocessor (µP) supervisory circuits reduce
the complexity and number of components required for
power-supply monitoring and battery-control functions
in µP systems. They significantly improve system relia-
bility and accuracy compared to separate ICs or
discrete components.
These devices are designed for use in systems powered
by 3.0V or 3.3V supplies. See the selector guide in the
back of this data sheet for similar devices designed for
5V systems. The suffixes denote different reset threshold
voltages: 3.075V (T), 2.925V (S), and 2.625V (R) (see
Reset Threshold
section in the
Detailed Description).
All
these parts are available in 8-pin DIP and SO packages.
Functions offered in this series are as follows:
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____________________________Features
o
o
o
o
o
o
o
o
o
o
o
–——
——–
RESET and RESET Outputs
Manual Reset Input
Precision Supply-Voltage Monitor
200ms Reset Time Delay
Watchdog Timer (1.6sec timeout)
Battery-Backup Power Switching—
Battery Can Exceed V
CC
in Normal Operation
40µA V
CC
Supply Current
1µA Battery Supply Current
Voltage Monitor for Power-Fail or
Low-Battery Warning
–——
——–
Guaranteed RESET Assertion to V
CC
= 1V
8-Pin DIP and SO Packages
MAX690T/S/R, 704T/S/R, 802T/S/R, 804–806T/S/R
______________Ordering Information
PART**
MAX690_CPA
MAX690_CSA
MAX690_C/D
MAX690_EPA
MAX690_ESA
MAX690_MJA
TEMP. RANGE
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
PIN-PACKAGE
8 Plastic DIP
8 SO
Dice*
8 Plastic DIP
8 SO
8 CERDIP
Part
MAX690
MAX704
MAX802
MAX804
MAX805
MAX806
________________________Applications
Battery-Powered Computers and Controllers
Embedded Controllers
Intelligent Instruments
Automotive Systems
Critical µP Power Monitoring
Portable Equipment
__________________Pin Configuration
TOP VIEW
V
OUT
V
CC
GND
PFI
( ) ARE FOR MAX804T/S/R, MAX805T/S/R
< >
ARE FOR MAX704T/S/R, MAX806T/S/R
Call toll free 1-800-998-8800 for free samples or literature.
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________________________________________________________________
Maxim Integrated Products
Inp
1
2
3
4
±4%
±4%
±2%
±2%
±4%
±2%
±75mV
±75mV
±2%
±2%
±75mV
±2%
Ordering Information continued on last page.
* Contact factory for dice specifications.
** These parts offer a choice of reset threshold voltage. Select
the letter corresponding to the desired nominal reset threshold
voltage (T = 3.075V, S = 2.925V, R = 2.625V) and insert it into
the blank to complete the part number.
_________Typical Operating Circuits
REGULATED +3.3V OR +3.0V
UNREGULATED
DC
0.1µF
R1
V
CC
V
CC
RESET
(RESET)
PFO
3.6V
LITHIUM
BATTERY
PFI
MAX690T/S/R
WDI
MAX802T/S/R
MAX804T/S/R
MAX805T/S/R
VBATT
GND
0.1µF
V
OUT
0.1µF
V
CC
CMOS RAM
GND
µP
RESET
NMI
I/O LINE GND
BUS
MAX690T/S/R
MAX704T/S/R
MAX802T/S/R
MAX804T/S/R
MAX805T/S/R
MAX806T/S/R
DIP/SO
8
7
6
5
VBATT
RESET (RESET)
WDI
<
MR
>
PFO
R2
( ) ARE FOR MAX804T/S/R, MAX805T/S/R
See last page for MAX704T/S/R, MAX806T/S/R.
1
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