CAT1161/2

The CAT1161/2 is a complete memory and supervisory solution for microcontroller-based systems. A serial EEPROM memory (16K) with hardware memory write protection, a system power supervisor with brown out protection and a watchdog timer are integrated together in low power CMOS technology. Memory interface is via an I2C bus.

The 1.6-second watchdog circuit returns a system to a known good state if a software or hardware glitch halts or "hangs" the system. The CAT1161 watchdog monitors the SDA line, making an additional PC board trace unnecessary. The lower cost CAT1162 does not have a watchdog timer.

The power supply monitor and reset circuit protects memory and system controllers during power up/down and against brownout conditions. Five reset thresho voltages support 5V, 3.3V and 3V systems. If power supply voltages are out of tolerance reset signals become active, preventing the system microcontroller, ASIC or peripherals from operating. Reset signals become inactive typically 200 ms after the supply voltage exceeds the reset threshold level. With both active high and low reset signals, interface to microcontrollers and other ICs is simple. In addition, a reset pin can be used as a debounced input for push-button manual reset capability.

The CAT1161/2 memory features a 16-byte page. In addition, hardware data protection is provided by a write protect pin WP and 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 and a surface mount, 8-pin SO package.