CAT1161, CAT1162
Supervisory Circuits with
I2C Serial CMOS EEPROM,
Precision Reset Controller
and Watchdog Timer (16K)
http://onsemi.com
Description
The CAT1161/2 is a complete memory and supervisory solution for
microcontroller−based systems. A serial EEPROM memory (16K)
with hardware memory write protection, a system power supervisor
with brown out protection and a watchdog timer are integrated
together in low power CMOS technology. Memory interface is via an
PDIP−8
CASE 646AA
SOIC−8
CASE 751BD
2
I C bus.
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.
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 5 V, 3.3 V and 3 V
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
200 ms 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 pushbutton manual reset capability.
PIN CONFIGURATION
DC
1
8
V
CC
RESET
2
7
RESET
CAT1161
CAT1162
3
4
6
5
WP
SCL
SDA
GND
PIN FUNCTIONS
Pin Name
Function
DC
RESET
WP
Do Not Connect
Active Low Reset I/O
Write Protect
The CAT1161/2 memory features a 16−byte page. In addition,
hardware data protection is provided by a write protect pin WP and by
GND
SDA
Ground
a V sense circuit that prevents writes to memory whenever V falls
CC
CC
Serial Data/Address
Clock Input
below the reset threshold or until V reaches the reset threshold
CC
SCL
during power up.
Available packages include an 8−pin DIP and a surface mount,
8−pin SO package.
RESET
Active High Reset I/O
Power Supply
V
CC
Features
• Watchdog Monitors SDA Signal (CAT1161)
ORDERING INFORMATION
2
• 400 kHz I C Bus Compatible
For Ordering Information details, see page 11.
• 2.7 V to 6 V Operation
• Low Power CMOS Technology
• 16−Byte Page Write Buffer
• 1,000,000 Program/Erase Cycles
• Built−in Inadvertent Write Protection
• Manual Reset
♦ V Lock Out
CC
♦ Write Protection Pin, WP
• 100 Year Data Retention
• Active High or Low Reset
• 8−Pin DIP or 8−Pin SOIC
♦ Precision Power Supply Voltage Monitor
♦ 5 V, 3.3 V and 3 V Systems
• Commercial and Industrial Temperature Ranges
• These Devices are Pb−Free, Halogen Free/BFR Free
♦ Five Threshold Voltage Options
and are RoHS Compliant
© Semiconductor Components Industries, LLC, 2012
1
Publication Order Number:
July, 2012 − Rev. 12
CAT1161/D