The 1338 is a serial real-time clock (RTC) device that consumes ultra-low power and provides a full binary-coded decimal (BCD) clock/calendar with 56 bytes of battery backed Non-Volatile Static RAM. The clock/calendar provides seconds, minutes, hours, day, date, month, and year information. The clock operates in either the 24-hour or 12-hour format with AM/PM indicator. The end of the month date is automatically adjusted for months with fewer than 31 days, including corrections for leap year. Access to the clock/calendar registers is provided by an I2C interface capable of operating in fast I2C mode. Built-in Power-sense circuitry detects power failures and automatically switches to the backup supply, maintaining time and date operation.


  • Real-Time Clock (RTC) counts seconds, minutes, hours, day, date, month, and year with leap-year compensation valid up to 2100
  • 56-Byte battery-backed Non Volatile RAM for data storage
  • Fast mode I2C Serial interface
  • Automatic power-fail detect and switch circuitry
  • Programmable square-wave output
  • Packaged in 8-pin MSOP, 8-pin SOIC, or 16-pin SOIC (surface-mount package with an integrated crystal)
  • Industrial temperature range (-40°C to +85°C)




Design & Development

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Boards & Kits