The CAT1027 is a complete memory and supervisory solution for microcontroller-based systems. A EEPROM Serial 2-Kb CPU Supervisor 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 VCCsense 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 aRESEToutput. In addition, theRESETpin can be used as an input for push-button manual reset capability.The CAT1027 provides an auxiliary voltage sensor input, VSENSE, which is used to monitor a second system supply. The auxiliary high impedance comparator drives the open drain output, VLOW, 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 VCCsense circuit that prevents writes to memory whenever VCCfalls below the reset threshold or until VCCreaches 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.