9-1
24C1601 BLOCK
CAT24C321/322(32K), CAT24C641/642(64K)
Supervisory Circuits with I
2
C Serial CMOS E
2
PROM, Precision Reset Controller and Watchdog Timer
DESCRIPTION
The CAT24CXXX is a single chip solution to three
popular functions of EEPROM memory, precision reset
controller and watchdog timer. The 24C321/322(32K)
and 24C641/642(64K) feature a I
2
C Serial CMOS
EEPROM. Catalyst's advanced CMOS technology sub-
stantially reduces device power requirements. The
24CXXX features a 32-byte page and is available in 8-pin
DIP or 8-pin SOIC packages.
The reset function of the 24CXXX protects the system
during brown out and power up/down conditions. During
system failure the watchdog timer feature protects the
microcontroller with a reset signal. 24CXXX features
active low reset on pin 2 and active high reset on pin 7.
24C321/641 features watchdog timer on the SDA line.
24C322/642 does not feature the watchdog timer func-
tion.
Pin Name Function
SDA Serial Data/Address
RESET/RESET Reset I/O
SCL Clock Input
Vcc Power Supply
DC Do not Connect
V
SS
Ground
WP Write Protect
PIN FUNCITONS
PIN CONFIGURATION
24C321/322*
24C641/642*
BLOCK DIAGRAM
*All products offered in P and J packages
Advanced
FEATURES
© 1998 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
n Watchdog Timer on SDA for 24C321/641
n Programmable Reset Threshold
n 400 KHz I
2
C Bus Compatible
n 2.7 to 6 Volt Operation
n Low Power CMOS Technology
n 32 - Byte Page Write Buffer
n Built-in inadvertent write protection
— V
CC
Lock Out
n Active High or Low Reset Outputs
— Precision Power Supply Voltage Monitoring
— 5V, 3.3V and 3V options
n 1,000,000 Program/Erase Cycles
n 100 Year Data Retention
n 8-Pin DIP or 8-Pin SOIC
n Commercial, Industrial and Automotive
Temperature Ranges
Doc. No. 25083-00 12/98
DC
V
CC
RESET
SCL
SDA
RESET
WP
V
SS
D
OUT
ACK
SENSE AMPS
SHIFT REGISTERS
CONTROL
LOGIC
WORD ADDRESS
BUFFERS
START/STOP
LOGIC
E
2
PROM
V
CC
EXTERNAL LOAD
COLUMN
DECODERS
XDEC
DATA IN STORAGE
HIGH VOLTAGE/
TIMING CONTROL
V
SS
WP
SDA
RESET Controller
High
Precision
Vcc Monitor
STATE COUNTERS
SLAVE
ADDRESS
COMPARATORS
SCL
Only for
24C321/641
RESET/RESET
WATCHDOG