DS1642-100+ (MAXIM INTEGRATED PRODUCTS)

The DS1642-100+ is a non-volatile timekeeping RAM in 24 pin EDIP package. This device is a 2k x 8 static RAM with fully functional real time clock (RTC) which can be accessible in a bytewide format. It can be easily substituted in ROM and EEPROM sockets providing read/write non-volatility and the addition of the real time clock function. The RTC registers contain year, month, date, day, hours, minutes and seconds data in 24-hour BCD format. Corrections for the day of the month and leap year are made automatically. The RTC clock registers are double-buffered to avoid access of incorrect data that can occur during clock update cycles. DS1642 contains its own power-fail circuitry which deselects the device when the VCC supply is in an out of tolerance condition. This feature prevents loss of data from unpredictable system operation brought on by low VCC as errant access and update cycles are avoided.