MAX690A Datasheet, PDF (1/12 Pages) Maxim Integrated Products – Microprocessor Supervisory Circuits

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 (µP) 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
µP, 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 ±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.
_______________________Applications
Battery-Powered Computers and Controllers
Intelligent Instruments
Automotive Systems
Critical µP Power Monitoring
__________Typical Operating Circuit
UNREGULATED DC REGULATED +5V
O.1µF
R1
R2
3.6V
LITHIUM
BATTERY
VCC _RESET
PFO
PFI
WDI
V_BATTGNDVOUT
MAX690A
MAX802L
VCC
RESET
NMI ^µP
I/O LINE _GND
VCC
CMOS
RAM
GND
___________________________Features
o Precision Supply-Voltage Monitor:
4.65V for MAX690A/MAX802L/MAX805L
4.40V for MAX692A/MAX802M
o Reset Time Delay – 200ms
o Watchdog Timer – 1.6sec Timeout
o Battery-Backup Power Switching
o 200µA 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 ±2%
(MAX802L/M)
o Guaranteed RESET Assertion to V_CC = 1V
o 8-Pin SO and DIP Packages
______________Ordering Information
PART
MAX690ACPA
MAX690ACSA
MAX690AC/D
MAX690AEPA
MAX690AESA
MAX690AMJA
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**
Ordering Information continued on last page.
* Dice are specified at T_A = +25°C
**Contact factory for availability and processing to MIL-STD-883.
_________________Pin Configurations
TOP VIEW
VOUT ₁
V_CC 2
GND 3
PFI 4
MAX690A
MAX692A
MAX802L
MAX802M
MAX805L
8 VBATT
7 RESET (RESET)
6 WDI
5 PFO
DIP/SO
( ) ARE FOR MAX805L ONLY.
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