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Industrial and extended temperature ranges
DESCRIPTION
The CAT1026 and CAT1027 are complete memory and
supervisory solutions for microcontroller-based systems.
A 2k-bit 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 CAT1026 and CAT1027 provide a precision V
CC
sense circuit with five reset threshold voltage options
that support 5V, 3.3V and 3V systems. The power
supply monitor and reset circuit protects memory and
systems controllers during power up/down and against
brownout conditions. If power supply voltages are out of
tolerance reset signals become active preventing the
system microcontroller, ASIC, or peripherals from
operating.
used as an input for push-button manual reset capability.
The CAT1026 and CAT1027 provide an auxiliary voltage
sensor input, V
SENSE
, which is used to monitor a second
system supply. The auxiliary high impedance comparator
drives the open drain output, V
LOW
, whenever the sense
voltage is below 1.25V threshold.
The CAT1027 is designed with a 1.6 second watchdog timer
circuit that resets a system to a known state if software or a
hardware glitch halts or 鈥渉angs鈥?the system. The CAT1027
features a watchdog timer interrupt input, WDI.
The on-chip 2k-bit EEPROM 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
The CAT1026 features two open drain reset outputs: reset threshold during power up.
one (RESET) drives high and the other (RESET) drives Available packages include an 8-pin DIP, 8-pin SOIC, 8-
low whenever V
CC
falls below the threshold. Reset pin TSSOP, 8-pin TDFN and 8-pin MSOP. The TDFN
outputs become inactive typically 200 ms after the package thickness is 0.8mm maximum. TDFN footprint is
supply voltage exceeds the reset threshold value. With 3x3mm.
both active high and low reset signals, interface to
microcontrollers and other ICs is simple. CAT1027 has
only a
RESET
output. In addition, the
RESET
pin can be
漏 2004 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
Doc No. 3010, Rev. K