CAT1161

CAT1161, CAT1162 Supervisory Circuits with I2C Serial CMOS EEPROM, Precision Reset Controller and Watchdog Timer (16K) Description 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 threshold voltages support 5 V, 3.3 V and 3 V 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 pushbutton manual reset capability. The CAT1161/2 memory features a 16−byte page. In addition, hardware data protection is provided by a wr...