CAT1027

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 I² 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.

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, 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 1.25V 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 VCC sense circuit that prevents writes to memory whenever VCC falls below the reset threshold or until VCC 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.