The ISL1208 device is a low power real time clock with timing and crystal compensation, clock/calendar, power fail indicator, periodic or polled alarm, intelligent battery backup switching and battery-backed user SRAM. The oscillator uses an external, low-cost 32. 768kHz crystal. The real time clock tracks time with separate registers for hours, minutes, and seconds. The device has calendar registers for date, month, year and day of the week. The calendar is accurate through 2099, with automatic leap year correction.


  • Real Time Clock/Calendar
  • Tracks Time in Hours, Minutes, and Seconds
  • Day of the Week, Day, Month, and Year
  • 15 Selectable Frequency Outputs
  • Single Alarm
  • Settable to the Second, Minute, Hour, Day of the Week, Day, or Month
  • Single Event or Pulse Interrupt Mode
  • Automatic Backup to Battery or Super Capacitor
  • Power Failure Detection
  • On-Chip Oscillator Compensation
  • 2 Bytes Battery-Backed User SRAM
  • I2C Interface
  • 400kHz Data Transfer Rate
  • 400nA Battery Supply Current
  • Same Pin Out as ST M41Txx and Maxim DS13xx Devices
  • Small Package Options
  • 8 Ld MSOP and SOIC Packages
  • 8 Ld TDFN Package
  • Pb-Free Available (RoHS Compliant)



  • Utility Meters
  • HVAC Equipment
  • Audio/Video Components
  • Set-Top Box/Television
  • Modems
  • Network Routers, Hubs, Switches, Bridges
  • Cellular Infrastructure Equipment
  • Fixed Broadband Wireless Equipment
  • Pagers/PDA
  • POS Equipment
  • Test Meters/Fixtures
  • Office Automation (Copiers, Fax)
  • Home Appliances
  • Computer Products


Document title Document type
Date Date
PDF 1.06 MB Datasheet
PDF 302 KB Application Note
PDF 329 KB Application Note
PDF 4.91 MB 日本語 Brochure
PDF 603 KB End Of Life Notice
PDF 815 KB Manual - Development Tools
PDF 443 KB Manual - Development Tools
PDF 913 KB Manual - Development Tools
PDF 243 KB Other
PDF 266 KB Other
PDF 302 KB Other
PDF 264 KB Other
PDF 232 KB Other
PDF 1.83 MB Overview
PDF 208 KB Price Increase Notice
PDF 363 KB Product Advisory
PDF 126 KB Product Change Notice
PDF 152 KB Product Change Notice
PDF 135 KB Product Change Notice
19 items

Design & Development

Software & Tools

Software Downloads

Software title Software type Type Date Date
PDF 603 KB End Of Life Notice
EXE 7.85 MB Library
EXE 1.62 MB Library
EXE 3.02 MB Library
PDF 846 KB Software & Tools - Other
5 items

Boards & Kits

Boards & Kits