The Maxim DS14285SN is a Real Time Clock. The DS14285/DS14287 real-time clock with NV RAM control provides the industry standard DS1287 clock function with the additional feature of providing nonvolatile control for an external SRAM. Functions include a nonvolatile time-of-day clock, alarm, 100-year calendar, programmable interrupt, square wave generator, and 114 bytes of nonvolatile static RAM. For the DS14287 a lithium energy source, quartz crystal, and write protection circuitry are contained within a 24-pin dual in-line package. A standard 32.768kHz quartz crystal can be directly connected to the DS14285 via pins 1 and 2 (X1, X2). For more information on crystal selection and crystal layout considerations, please consult Application Note 58, Crystal Considerations with Dallas Real-time Clocks. The DS14285/DS14287 uses its backup energy source and battery-backup controller to make a standard CMOS static RAM nonvolatile during power-fail conditions. For the DS14287 the internal lithium cell is electrically isolated from the clock and memory when shipped from the factory.
