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MCP7940N

Battery-Backed I2C Real-Time Clock/Calendar with SRAM

Status: In Production

Features:

  • 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
  • Time logged on switchover to and from Battery Backup
  • 64 Bytes Battery-Backed SRAM
  • I2C Clock Frequency up to 400 kHz
  • Operating Voltage 1.8V to 5.5V
  • Backup Voltage 1.3V to 5.5V
  • Low Typical Timekeeping Current
  • Automatic Switchover to Battery Backup
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Overview
Documents
Development Environment
Similar Devices
RoHS Information
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Device Overview

Summary

The MCP7940N series of low-power Real-Time Clocks (RTC) 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 low-cost 32.768 kHz 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-hour 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 4.096 kHz and 1 Hz can be generated from the external crystal. The device is fully accessible through the serial interface while VCC is between 1.8V and 5.5V, but can operate down to 1.3V for timekeeping and SRAM retention only.

Additional Features
      Timekeeping
      • 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
      • 64 Bytes Battery-Backed SRAM
      • 2-Wire Serial Interface, I2C™Compatible
        • I2C Clock Frequency up to 400 kHz
      Low-Power
      • Wide Voltage Range
        • Operating Voltage 1.8V to 5.5V
        • Backup Voltage 1.3V to 5.5V
      • Low Typical Timekeeping Current
      • Automatic Switchover to Battery Backup
Parametrics
Name
Value
Max Communications Speed
400 kHz
Pin Count
8
Minimum Clock Count (seconds)
1 sec
Battery-backed SRAM (Bytes)
64
Temperature Range (C)
-40 to +125

Documents

Jump to:

Data Sheet

Errata

Migration Guide

Gerber Files

Code Examples

08/21/2012
61KB
08/21/2012
152KB

Development Environment

  • Demo & Evaluation Boards
Demo & Evaluation Boards
MCP79410 RTCC PICtail Plus Daughter Board
MCP79410 RTCC PICtail Plus Daughter Board ( AC164140 )

The MCP7941X RTCC PICtail™ Plus Daughter Board demonstrates the features and abilities of the MCP7941X and MCP7940X I²C™ Real-Time Clock/Calendar family in standard development platforms. By designing this daughter board with the PICtail Plus, PICtail and PICkit™ serial connectors, it will operate with the Explorer 16 Development Board, the PICDEM PIC18 Explorer Board, the...

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RoHS Information

Part Number
Device Weight (g)
Shipping Weight (Kg)
Lead Count
Package Type
Package Width
Solder Composition
JEDEC Indicator
RoHS
China EFUP
MCP7940N-I/P
0.486700
0.900000
8
PDIP
.300in
Matte Tin
e3
MCP7940N-E/SN
0.078000
0.160000
8
SOIC
.150In(3.90mm)
Matte Tin
e3
MCP7940NT-E/SN
0.078000
0.230303
8
SOIC
.150In(3.90mm)
Matte Tin
e3
MCP7940N-I/SN
0.078000
0.160000
8
SOIC
.150In(3.90mm)
Matte Tin
e3
MCP7940NT-I/SN
0.078000
0.230303
8
SOIC
.150In(3.90mm)
Matte Tin
e3
MCP7940NT-E/SNVAO
0.078000
0.230303
8
SOIC
.150In(3.90mm)
Matte Tin
e3
MCP7940N-I/ST
0.033000
0.090000
8
TSSOP
4.4mm
Matte Tin
e3
MCP7940NT-I/ST
0.033000
0.215600
8
TSSOP
4.4mm
Matte Tin
e3
MCP7940N-I/MS
0.025600
0.070000
8
MSOP
3x3mm
Matte Tin
e3
MCP7940NT-I/MS
0.025600
0.215600
8
MSOP
3x3mm
Matte Tin
e3
MCP7940N-E/MS
0.025600
0.070000
8
MSOP
3x3mm
Matte Tin
e3
MCP7940NT-E/MS
0.025600
0.215600
8
MSOP
3x3mm
Matte Tin
e3
MCP7940NT-I/MNY
0.014300
0.248485
8
TDFN
2x3x0.8mm
NiPdAu
e4
To see a complete listing of RoHS data for this device, please Click here
Shipping Weight = Device Weight + Packing Material weight. Please contact sales office if device weight is not available.

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