Preliminary Information
CAT1024, CAT1025
Supervisory Circuits with I
2
C Serial 2K CMOS EEPROM and Manual Reset
FEATURES
s
Precision power supply voltage monitor
s
Built-in inadvertent write protection
— 5V, 3.3V and 3V systems
— Five threshold voltage options
s
Active high or low reset
— WP pin (CAT1025)
s
1,000,000 Program/Erase cycles
s
Manual reset input
s
100 year data retention
s
8-pin DIP, SOIC, TSSOP, TDFN (MSOP
— Valid reset guaranteed at V
CC
=1V
s
400kHz I
2
C bus
s
2.7V to 5.5V operation
s
Low power CMOS technology
s
16-Byte page write buffer
(3x4.9mm) & 3x3mm foot prints) or MSOP
packages
s
Automotive, extended automotive and
industrial temperature ranges
DESCRIPTION
The CAT1024 and CAT1025 are complete memory and
supervisory solutions for microcontroller-based systems.
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 I
2
C bus.
The CAT1025 provides a precision V
CC
sense circuit
and two open drain outputs: one (RESET) drives high
and the other (RESET) drives low whenever V
CC
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 also provides a precision V
CC
sense
circuit, but has only a
RESET
output and does not have
a Write Protect input.
The power supply monitor and reset circuit protect
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 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 CAT1024/25 memory features a 16-byte page. In
addition, hardware data protection is provided by a V
CC
sense circuit that prevents writes to memory whenever V
CC
falls below the reset threshold or until V
CC
reaches the reset
threshold during power up.
Available packages include an 8-pin DIP and a surface
mount 8-pin SO, 8-pin TSSOP, 8-pin TDFN and 8-pin MSOP
packages. The TDFN package thickness is 0.8mm maximum.
TDFN footprint options are 3x3mm or 3x4.9mm (MSOP pad
layout).
(Bottom View)
TDFN Package: 3mm x 3mm
0.8mm maximum height - (RD4)
VCC
NC
SCL
SDA
8
7
1
2
PIN CONFIGURATION
(Bottom View)
TDFN Package: 3mm x 4.9mm
0.8mm maximum height - (RD2)
VCC
NC
SCL
SDA
8
7
1
2
MR
1
RESET
2
NC 3
VSS 4
CAT1024
8 VCC
7 NC
6 SCL
5 SDA
MR
RESET
NC
VSS
MR
RESET
NC
VSS
CAT1024
6
5
CAT1024
6
5
3
4
3
4
MR
1
RESET
2
RESET 3
VSS 4
CAT1025
8 VCC
7 WP
6 SCL
5 SDA
VCC
WP
SCL
SDA
8
7
1
2
MR
RESET
RESET
VSS
VCC
8
WP
7
SCL
6
SDA
5
1
MR
2
RESET
CAT1025
6
5
3
4
CAT1025
3
RESET
4
V
SS
© 2003 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
Doc No. 3008, Rev. G
CATALYST [ CATALYST SEMICONDUCTOR ]
