DESCRIPTION
The DS17285/DS17287 is a real time clock (RTC) designed as a successor to the industry standard DS1285, DS1385, DS1485, DS1585, and DS1685 PC real time clocks. This device provides the industry standard DS1285 clock function with either +3.0 or +5.0 volt operation . The DS17285 also incorporates a number of enhanced features including a silicon serial number, power on/off control circuitry, 114 bytes of user NV SRAM plus 2K bytes of additional NVRAM, and 32.768 KHz output for sustaining power management activities.

FEATURES
Incorporates industry standard DS1287 PC clock plus enhanced features:
• +3 or +5 volt operation
• SMI recovery stack
• 64–bit silicon serial number
• Power control circuitry supports system power on from date/time alarm or key closure
• 32 KHz output on power–up
• Crystal select bit allows RTC to operate with 6 pF or 12.5 pF crystal
• 114 bytes user NVRAM
• 2K bytes of additional NVRAM
• Auxiliary battery input
• RAM clear input
• Century register
• Date alarm register
• Compatible with existing BIOS for original DS1287 functions
• Available as chip (DS17285) or standalone module with embedded battery and crystal (DS17287)
• Timekeeping algorithm includes leap year compensation valid up to 2100