MCP7940N – I2C Real-Time Clock/Calendar with SRAM

MCP7940N – I2C Real-Time Clock/Calendar with SRAM

R 23.45

  • USD: $ 1.61

MCP7940N-I/P – Alarm RTC IC, Year/Month/Week/Date/Hr/Min/Sec 12Hr / 24Hr, I2C, 1.8 V to 5.5 V, DIP-8
Note: Specifications, Prices & Availability may change without notice. Images are for illustration purposes only. E&OE

Brand: Microchip

Availability: 5 in stock SKU: STC-00129 Categories: , Tags: ,
  • Description
  • Specification
  • Additional information
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The MCP7940N-I/P is a low-power battery-backed Real-Time Clock/Calendar (RTC) with SRAM uses digital timing compensation for an accurate clock/calendar, a programmable output control for versatility and a power sense circuit that automatically switches to the backup supply.

Using a 32.768kHz crystal, it tracks time using several internal registers.

For communication, the MCP7940N uses the I²C™ bus. The clock/calendar automatically adjusts for months with fewer than 31 days, including corrections for leap years. The clock operates in either the 24 or 12-hour format with an AM/PM indicator and settable alarm(s) to the second, minute, hour, day of the week, date or month.

Using the programmable CLKOUT, frequencies of 32.768, 8.192 and 4.096kHz and 1Hz can be generated from the external crystal. The device is fully accessible through the serial interface while VCC is between 1.8 and 5.5V, but can operate down to 1.3V for timekeeping and SRAM retention only.

  • 2-Wire Serial Interface, I2C™Compatible
    • Max Communications Speed: I2C Clock Frequency up to 400 kHz
  • Pin Count: 8
  • Minimum Clock Count (seconds): 1 sec
  • Battery-backed SRAM (Bytes): 64
  • Battery-Backed Real-Time Clock/Calendar (RTCC):
    • Hours, Minutes, Seconds, Day of Week, Day, Month, Year
    • Leap year compensated to 2399
    • 12/24 hour modes
  • On-Chip Digital Trimming/Calibration
    • 1 PPM Resolution
    • ±129 PPM Range
  • Dual Programmable Alarms
  • Versatile Output Pin
    • Clock output with selectable frequency
    • Alarm output
    • General Purpose output
  • Power-Fail Time-Stamp
    • Time logged on switchover to and from Battery Backup
  • Temperature Range (C): -40 to +125

Additional information

Weight3.4 g



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