19-4333; Rev 3; 9/93
Microprocessor Supervisory Circuits
__________________General Description
The MAX690A/MAX692A/MAX802L/MAX802M/MAX805L
reduce the complexity and number of components
required for power-supply monitoring and battery-control
functions in microprocessor (碌P) systems. They signifi-
cantly improve system reliability and accuracy compared
to separate ICs or discrete components.
These parts provide four functions:
1) A reset output during power-up, power-down, and
brownout conditions.
2) Battery-backup switching for CMOS RAM, CMOS
碌P, or other low-power logic.
3) A reset pulse if the optional watchdog timer has not
been toggled within 1.6sec.
4) A 1.25V threshold detector for power-fail warning or
low-battery detection, or to monitor a power supply
other than +5V.
The parts differ in their reset-voltage threshold levels
and reset outputs. The MAX690A/MAX802L/MAX805L
generate a reset pulse when the supply voltage drops
below 4.65V, and the MAX692A/MAX802M generate a
reset below 4.40V. The MAX802L/MAX802M guaran-
tee power-fail accuracies to 卤2%. The MAX805L is the
same as the MAX690A except that RESET is provided
instead of
RESET.
All parts are available in 8-pin DIP and SO packages.
The MAX690A/MAX802L are pin compatible with the
MAX690 and MAX694. The MAX692A/MAX802M are
pin compatible with the MAX692.
___________________________Features
o
Precision Supply-Voltage Monitor:
4.65V for MAX690A/MAX802L/MAX805L
4.40V for MAX692A/MAX802M
o
Reset Time Delay 鈥?200ms
o
Watchdog Timer 鈥?1.6sec Timeout
o
Battery-Backup Power Switching
o
200碌A Quiescent Supply Current
o
50nA Quiescent Supply Current in Battery-
Backup Mode
o
Voltage Monitor for Power-Fail or Low-Battery
Warning
o
Power-Fail Accuracy Guaranteed to 卤2%
(MAX802L/M)
o
Guaranteed
RESET
Assertion to V
CC
= 1V
o
8-Pin SO and DIP Packages
MAX690A/MAX692A/MAX802L/MAX802M/MAX805L
______________Ordering Information
PART
MAX690ACPA
MAX690ACSA
MAX690AC/D
MAX690AEPA
MAX690AESA
MAX690AMJA
TEMP. RANGE
0掳C to +70掳C
0掳C to +70掳C
0掳C to +70掳C
-40掳C to +85掳C
-40掳C to +85掳C
-55掳C to +125掳C
PIN-PACKAGE
8 Plastic DIP
8 SO
Dice*
8 Plastic DIP
8 SO
8 CERDIP**
_______________________Applications
Battery-Powered Computers and Controllers
Intelligent Instruments
Automotive Systems
Critical 碌P Power Monitoring
Ordering Information continued on last page.
* Dice are specified at T
A
= +25掳C
**Contact factory for availability and processing to MIL-STD-883.
_________________Pin Configurations
TOP VIEW
__________Typical Operating Circuit
UNREGULATED DC REGULATED +5V
O.1碌F
V
CC
V
CC
PFI
R
2
3.6V
LITHIUM
BATTERY
RESET
PFO
WDI
V
BATT
V
OUT
GND
RESET
NMI
碌P
V
CC
V
OUT
1
2
8
V
BATT
RESET (RESET)
WDI
PFO
R
1
GND
3
PFI
4
I/O LINE GND
BUS
V
CC
CMOS
RAM
GND
MAX690A
MAX692A
MAX802L
MAX802M
MAX805L
DIP/SO
7
6
5
MAX690A
MAX802L
( ) ARE FOR MAX805L ONLY.
________________________________________________________________
Maxim Integrated Products
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Call toll free 1-800-998-8800 for free samples or literature.
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