The SM8580A is a real-time clock IC based on a 32.768kHz crystal oscillator, which features a 4-bit parallel interface for communication with an external microcontroller. It comprises second-counter to year-counter clock and calendar circuits that feature automatic leap-year adjustment up to year 2099, alarm and timer interrupt functions, clock counter change detect functions, ±30-second correction function, time error correction function, and built-in temperature sensor. The 4-bit parallel interface is compatible with general-purpose SRAM over a high-speed bus.

Block Diagram


  • High-speed bus 4-bit parallel interface
  • Built-in temperature sensor (analog voltage output)
  • -195 to +192ppm time error correction range
  • 2 software-maskable alarm and timer interrupt outputs
  • Date, day, hour, minute, and second-counter presettable alarm interrupt
  • 1/4096 seconds to 255 minutes presettable interval timer interrupt function
  • 2.4 to 5.5V interface voltage range
  • 1.6 to 5.5V clock voltage range
  • 0.6µA/3V (typ) current consumption
  • Package:SSOP-24-100054-1


8580_nc9915fe(148.7 KB)