CAT1161, CAT1162
Supervisory Circuits with I2C Serial CMOS EEPROM,
Precision Reset Controller and Watchdog Timer (16K)
write protection, a system power supervisor with
FEATURES
brown out protection and a watchdog timer are
integrated together in low power CMOS technology.
Memory interface is via an I2C bus.
Watchdog monitors SDA signal (CAT1161)
400kHz I2C bus compatible
2.7V to 6.0V operation
The 1.6-second watchdog circuit returns a system to a
known good state if a software or hardware glitch
halts or “hangs” the system. The CAT1161 watchdog
monitors the SDA line, making an additional PC board
trace unnecessary. The lower cost CAT1162 does not
have a watchdog timer.
Low power CMOS technology
16-Byte page write buffer
Built-in inadvertent write protection
—
—
V
CC lock out
Write protect pin, WP
The power supply monitor and reset circuit protects
memory and system controllers during power up/down
and against brownout conditions. Five reset threshold
voltages support 5V, 3.3V and 3V systems. If power
supply voltages are out of tolerance reset signals
become active, preventing the system microcontroller,
ASIC or peripherals from operating. Reset signals
become inactive typically 200ms after the supply
voltage exceeds the reset threshold level. With both
active high and low reset signals, interface to
microcontrollers and other ICs is simple. In addition, a
reset pin can be used as a debounced input for push-
button manual reset capability.
Active high or low reset
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—
—
Precision power supply voltage monitor
5V, 3.3V and 3V systems
Five threshold voltage options
1,000,000 Program/Erase cycles
Manual Reset
100 Year data retention
8-pin DIP or 8-pin SOIC
Commercial and industrial temperature ranges
The CAT1161/2 memory features a 16-byte page. In
addition, hardware data protection is provided by a
write protect pin WP and by a VCC sense circuit that
prevents writes to memory whenever VCC falls below
the reset threshold or until VCC reaches the reset
threshold during power up.
For Ordering Information details, see page 13.
DESCRIPTION
The CAT1161/2 is a complete memory and supervi-
sory solution for microcontroller-based systems. A se-
rial EEPROM memory (16K) with hardware memory
Available packages include an 8-pin DIP and a
surface mount, 8-pin SO package.
PIN CONFIGURATION
PIN FUNCTIONS
PDIP 8 Lead
SOIC 8 Lead
Pin Name Function
DC
Do not Connect
Active Low Reset I/O
Write Protect
DC
1
2
3
4
8
7
6
5
VCC
¯¯¯¯¯¯
RESET
¯¯¯¯¯¯
RESET
RESET
SCL
CAT1161
CAT1162
WP
GND
SDA
WP
Ground
GND
SDA
Serial Data/Address
Clock Input
SCL
RESET
VCC
Active High Reset I/O
Power Supply
© 2007 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
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Doc. No. 3002 Rev. F