CAT1026 Datasheet, PDF (1/20 Pages) Catalyst Semiconductor – Dual Voltage Supervisory Circuits with I2C Serial 2k-bit CMOS EEPROM

CAT1026, CAT1027
Dual Voltage Supervisory Circuits with I²C Serial 2k-bit CMOS EEPROM
FEATURES
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■ Precision V_CC power supply voltage monitor
— 5V, 3.3 V and 3 V systems
— Five threshold voltage options
■ Additional voltage monitoring
— Externally adjustable down to 1.25 V
■ Watchdog timer (CAT1027 only)
■ Active high or low reset
— Valid reset guaranteed to V_CC = 1 V
■ 400 kHz I²C bus
■ 3.0 V to 5.5 V operation
■ Low power CMOS technology
■ 16-Byte page write buffer
■ Built-in inadvertent write protection
■ 1,000,000 Program/Erase cycles
■ Manual reset capability
■ 100 year data retention
■ 8-pin DIP, SOIC, TSSOP, MSOP or TDFN
(3 x 3 mm foot-print) packages
— TDFN max height is 0.8mm
■ 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 I²C 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.
The CAT1026 features two open drain reset outputs:
one (RESET) drives high and the other (RESET) drives
low whenever VCC falls below the threshold. Reset
outputs become inactive typically 200 ms after the
supply voltage exceeds the reset threshold value. With
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
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 “hangs” 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
reset threshold during power up.
Available packages include an 8-pin DIP, 8-pin SOIC, 8-
pin TSSOP, 8-pin TDFN and 8-pin MSOP. The TDFN
package thickness is 0.8mm maximum. TDFN footprint is
3x3mm.
© 2004 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
Doc No. 3010, Rev. K