MCP7940M

The MCP7940M I2CTM compatible real-time clock/calendar (RTCC) includes SRAM and a digital trimming circuit for accuracy which is normally found in higher priced devices. Using a low-cost 32,768 kHz crystal or other clock source, time is tracked in either a 12-hour or 24-hour format with an AM/PM indicator and timing to the second, minute, hour, day of the week, day, month and year. As an interrupt or wakeup signal, a multifunction open drain output can be programmed as an Alarm Out or as a Clock Out that supports 4 selectable frequencies.

Features
  • Real-Time Clock/Calendar (RTCC) Hours, Minutes, Seconds, Day of Week, Day, Month, Year Leap year compensated  to 2399 12/24 hour modes
  • 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
  • 1 PPM Resolution
  • ±129 PPM Range
  • Dual Programmable Alarms
  • Versatile Output Pin Clock output with selectable frequency Alarm output General Purpose output
  • Clock output with selectable frequency
  • Alarm output
  • General Purpose output
  • 64 Bytes SRAM
  • 2-Wire Serial Interface, I2C™Compatible I2C Clock Frequency up to 400 kHz
  • I2C Clock Frequency up to 400 kHz
  • Wide Voltage Range Operating Voltage 1.8V to 5.5V
  • Operating Voltage 1.8V to 5.5V
  • Low Typical Timekeeping Current
Parameter
Parameter Name Value Value
Max Communications Speed 400 KHz 400 KHz
Pin Count 8 8
Minimum Clock Count (seconds) 1 sec 1 sec
Battery-backed SRAM (Bytes) 64 64
Temperature Range (C) -40 to +85 -40 to +85
Documents
MCP7940M Low-Cost I2C RTCC with SRAMData Sheets06/23/20141266KB
MCP7940M Family Silicon ErrataErrata12/15/201570KB
AN1355 - A Complete Electronic Watch Based on MCP79410 I2C? RTCCAppNote06/23/2016154KB
AN1364 - Using the Alarm Feature on the MCP79410 RTCC to Implement a Delayed AlarmAppNote10/20/2010123KB
AN1365 - Recommended Usage of Microchip Serial RTCC DevicesAppNote03/28/2013267KB
AN1413 - Temperature Compensation of a Tuning Fork Crystal Based on MCP79410AppNote11/07/2011479KB
AN1414 - Using HI-TECH C Compiler to Interface RTCC Devices to 8-Bit PIC MCUsAppNote01/31/20124847KB
AN1491 - Configuring the MCP794XX RTCC FamilyAppNote01/25/2013246KB
AN1496 - Debugging Stand-Alone Real-Time Clock/Calender-based ApplicationsAppNote02/22/2013215KB
AN1519 - Recommended Crystals for Microchip Stand-Alone Real-Time Clock/Calendar DevicesAppNote09/16/2013397KB
TB3116 - Questions and Answers Concerning MCP79XXX Serial RTCCsAppNote08/11/201475KB
Enabling Intelligent Automation Using the MCP7941X I2C RTCCTech Briefs10/21/201074KB
AN1355 PIC18F Source CodeSample Code08/21/201261KB
AN1355 PIC24F Source CodeSample Code08/21/2012152KB
Ordering Information
Part NumberLeadsPackage TypeTemp RangePacking1+26+100+1000+5000+
MCP7940M-I/MS8MSOP-40C to +85CTUBE0.620.570.540.510.50
MCP7940M-I/P8PDIP-40C to +85CTUBE0.640.590.560.530.51
MCP7940M-I/SN8SOIC-40C to +85CTUBE0.580.540.510.480.46
MCP7940M-I/ST8TSSOP-40C to +85CTUBE0.620.570.540.510.50
MCP7940MT-I/MNY8TDFN-40C to +85CT/R0.660.610.580.540.53
MCP7940MT-I/MS8MSOP-40C to +85CT/R0.620.570.540.510.50
MCP7940MT-I/SN8SOIC-40C to +85CT/R0.580.540.510.480.46
MCP7940MT-I/ST8TSSOP-40C to +85CT/R0.620.570.540.510.50
Similar Devices
ProductPrice5K
MCP79400$0.66
MCP79401$0.72
MCP79402$0.72
MCP7940M$0.46
MCP7940N$0.59
MCP79410$0.72
MCP79411$0.78
MCP79412$0.78
MCP79510$0.90
MCP79511$0.96
MCP79512$0.96
MCP79520$0.96
MCP79521$1.02
MCP79522$1.02
MCP795W10$1.22
MCP795W11$1.28
MCP795W12$1.28
MCP795W20$1.28
MCP795W21$1.34
MCP795W22$1.34
RoHS Information
PartNumberDeviceWeightShippingWeightLeadCountPackageTypePackageWidthSolderCompositionJEDECIndicatorRoHSChinaEFUP
MCP7940M-I/P0.4867000.9000008PDIP.300inMatte Tine3
MCP7940MT-I/SN0.0780000.2303038SOIC.150In(3.90mm)Matte Tine3
MCP7940M-I/SN0.0780000.1600008SOIC.150In(3.90mm)Matte Tine3
MCP7940MT-I/ST0.0330000.2156008TSSOP4.4mmMatte Tine3
MCP7940M-I/ST0.0330000.0900008TSSOP4.4mmMatte Tine3
MCP7940MT-I/STVAO0.0330000.2156008TSSOP4.4mmMatte Tine3
MCP7940M-I/MS0.0256000.0700008MSOP3x3mmMatte Tine3
MCP7940MT-I/MS0.0256000.2156008MSOP3x3mmMatte Tine3
MCP7940MT-I/MNY0.0143000.2484858TDFN2x3x0.8mmNiPdAue4
MCP7940M Low-Cost I2C RTCC with SRAM MCP7940M
MCP7940M Family Silicon Errata MCP7940M
AN1355 MCP79412
AN1355 Source Code MCP79412
AN1364 MCP79412
AN1364 Source Code MCP79412
AN1365 MCP795W22
AN1413 MCP79520
AN1413 Source Code MCP79520
AN1414 MCP79412
Source Code AN1414 MCP79412
AN1491 MCP79412
01491 Source Code MCP79412
AN1491 Source Code MCP79412
AN1496 MCP79412
AN1519 MCP795W22
TB3116 MCP795W22
Enabling Intelligent Automation Using the MCP7941X I2C RTCC MCP79412
AN1355 PIC18F Source Code MCP79412
AN1355 PIC24F Source Code MCP79412