X5645

Replaces X25643/X25645 X5643/X5645 CPU Supervisor with 64Kbit SPI EEPROM FEATURES Selectable watchdog timer Low VCC detection and reset assertion —Five standard reset threshold voltages —Re-program low VCC reset threshold voltage using special programming sequence —Reset signal valid to VCC = 1V Determine watchdog or low voltage reset with a volatile flag bit Long battery life with low power consumption —<50µA max standby current, watchdog on —<1µA max standby current, watchdog off —<400µA max active current during read 64Kbits of EEPROM Built-in inadvertent write protection —Power-up/power-down protection circuitry —Protect 0, 1/4, 1/2 or all of EEPROM array with Block Lock™ protection —In circuit programmable ROM mode 2MHz SPI interface modes (0,0 & 1,1) Minimize EEPROM programming time —32-byte page write mode —Self-timed write cycle —5ms write cycle time (typical) 2.7V to 5.5V and 4.5V to 5.5V power supply operation Available packages —8-lead PDIP, 14-lead SOIC BLOCK DIAGRAM DESCRIPTION These devices combine four popular functions, Poweron Reset Control, Watchdog Timer, Supply Voltage Supervision, and Block Lock Protect Serial EEPROM Memory in one package. This combination lowers system cost, reduces board space requirements, and increases reliability. Applying power to the device activates the power on reset circuit which holds RESET/RESET active for a period of time. This allows the power supply and oscillator to stabilize before the processor can...