The CAT1027 is a complete memory and supervisory solution for microcontroller-based systems. A 2 k-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 400 kHz I2C bus.
The CAT1027 provides a precision V
sense circuit with five reset threshold voltage options that support 5.0 V, 3.3 V and 3.0 V 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.
CAT1027 has only a
output. In addition, the
pin can be used as an input for push-button manual reset capability.
The CAT1027 provides an auxiliary voltage sensor input, V
, which is used to monitor a second system supply. The auxiliary high impedance comparator drives the open drain output, V
, whenever the sense voltage is below 1.25 V 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 2 k-bit EEPROM memory features a 16-byte page. In addition, hardware data protection is provided by a V
sense circuit that prevents writes to memory whenever V
falls below the reset threshold or until V
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 0.8 mm maximum. TDFN footprint is 3x3 mm.

• Precision V
• power supply voltage supervisor
• 5.0 V, 3.3 V and 3.0 V systems
• Five threshold voltage options
• Additional voltage monitoring
• — Externally adjustable down to 1.25 V
• Watchdog timer
• Active high or low reset
• — Valid reset guaranteed to V
• = 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