Xicor's real-time clock chips support two-wire interface

Two real-time clock (RTC) chips from Xicor Inc. contain 32K-by-8 bits of EEPROM that can be used for phone book functions, calibration parameters, serialization, user memory or any other function requiring byte-addressable, nonvolatile storage.

The embedded EEPROM in the X1288 and X1286 can replace stand-alone memory and can reduce an end product's overall component count and cost. Besides the memory, the X1288 includes CPU supervisor functions, such as a watchdog timer, programmable low-voltage detection circuits and power-on-reset circuits. The watchdog timer supports user-selectable timeout intervals ranging from 250ms to 1.75s.

Both chips support an industry-standard two-wire interface for direct control and communication to the real-time clock/calendar and memory through a microcontroller. Both also feature an alarm architecture that allows designers to set up time- or calendar-driven alarms with resolutions of subsecond, second, minute, hour, day, day of the week or month.

An on-chip oscillator compensation feature eliminates the need for an external resistance-capacitance circuit. A user-selectable frequency output option allows designers to generate square waves of 32.768kHz, 100Hz or 1Hz from the real-time clock.

The chips operate over a 1.8V to 5.5V range, and they include a battery switchover function that supports automatic switching from the main power supply to battery backup in the event of a power failure.

In quantities of 100 pieces, the X1286 is priced starting at $2.93, and the X1288 is priced from $3.22.

EE Times