Preliminary Information
CAT1024, CAT1025
Supervisory Circuits with I2C Serial 2K CMOS EEPROM and Manual Reset
FEATURES
■ Built-in inadvertent write protection
— WP pin (CAT1025)
■ Precision power supply voltage monitor
— 5V, 3.3V and 3V systems
— Five threshold voltage options
■ Active high or low reset
■ 1,000,000 Program/Erase cycles
■ Manual reset input
■ 100 year data retention
— Valid reset guaranteed at VCC=1V
■ 400kHz I2C bus
■ 8-pin DIP, SOIC, TSSOP, TDFN (MSOP
(3x4.9mm) & 3x3mm foot prints) or MSOP
packages
■ 2.7V to 5.5V operation
■ Low power CMOS technology
■ 16-Byte page write buffer
■ Automotive, extended automotive and
industrial temperature ranges
DESCRIPTION
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 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, the
RESET pin or a separate input, MR, can be used as an input
for push-button manual reset capability.
The CAT1024 and CAT1025 are complete memory and
supervisorysolutionsformicrocontroller-basedsystems.
A 2kbit serial EEPROM memory and a system power
supervisor with brown-out protection are integrated
together in low power CMOS technology. Memory
interface is via a 400kHz I2C bus.
The CAT1025 provides a precision VCC sense circuit
and two open drain outputs: one (RESET) drives high
and the other (RESET) drives low whenever VCC falls
below the reset threshold voltage. The CAT1025 also
has a Write Protect input (WP). Write operations are
disabled if WP is connected to a logic high.
The CAT1024/25 memory features a 16-byte page. In
addition, hardware data protection is provided 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.
The CAT1024 also provides a precision VCC sense
circuit, but has only a RESET output and does not have
a Write Protect input.
Available packages include an 8-pin DIP and a surface
mount8-pinSO,8-pinTSSOP,8-pinTDFNand8-pinMSOP
packages.TheTDFNpackagethicknessis0.8mmmaximum.
TDFN footprint options are 3x3mm or 3x4.9mm (MSOP pad
layout).
The power supply monitor and reset circuit protect
memory and system controllers during power up/down
and against brownout conditions. Five reset threshold
(Bottom View)
TDFN Package: 3mm x 3mm
0.8mm maximum height - (RD4)
(Bottom View)
TDFN Package: 3mm x 4.9mm
0.8mm maximum height - (RD2)
PIN CONFIGURATION
V
MR
1
2
3
4
8
7
6
5
8
7
6
5
1
2
3
4
V
MR
CC
NC
MR
RESET
NC
V
1
2
3
4
8
7
6
5
CC
NC
CC
RESET
NC
NC
RESET
NC
CAT1024
CAT1024
CAT1024
SCL
SDA
SCL
SDA
SCL
SDA
V
SS
V
SS
V
SS
V
MR
8
7
6
5
V
MR
1
1
1
2
3
4
8
8
7
6
5
MR
V
CC
CC
CC
RESET
RESET
WP
SCL
SDA
2
3
4
RESET
RESET
WP
SCL
SDA
7
6
5
RESET 2
WP
CAT1025
CAT1025
CAT1025
3
4
SCL
SDA
RESET
V
V
SS
V
SS
SS
© 2003 by Catalyst Semiconductor, Inc.
Doc No. 3008, Rev. G
Characteristics subject to change without notice
CATALYST [ CATALYST SEMICONDUCTOR ]
