MCP79410T-I/SN

The MCP7941X Real-Time Clock/Calendar (RTCC)

tracks time using internal counters for hours, minutes,

seconds, days, months, years, and day of week. Alarms

can be configured on all counters up to and including

months. For usage and configuration, the MCP7941X

supports I2C communications up to 400 kHz.

The open-drain, multi-functional output can be

configured to assert on an alarm match, to output a

selectable frequency square wave or as a general

purpose output.

The MCP7941X is designed to operate using a

32.768 kHz tuning fork crystal with external crystal load

capacitors. On-chip digital trimming can be used to

adjust for frequency variance caused by crystal

tolerance and temperature.

SRAM and timekeeping circuitry are powered from the

backup supply when main power is lost, allowing the

device to maintain accurate time and the SRAM

contents. The times when the device switches over to

the back-up supply and when primary power returns are

both logged by the power-fail timestamp.

The MCP7941X features 1 Kbit of internal nonvolatile

EEPROM with software write-protectable regions. There

is an additional 64 bits of protected nonvolatile memory

which is only writable after an unlock sequence, making

it ideal for storing a unique ID or other critical

information. The MCP79411 and MCP79412 are

preprogrammed with EUI-48 and EUI-64 addresses,

respectively. Custom programming is also available.

Operating Ranges

• 2-Wire Serial Interface, I2C Compatible:

- I2C clock rate up to 400 kHz

• Temperature Range:

- Industrial (I): -40°C to +85°C

Packages

• 8-Lead SOIC, MSOP, TSSOP and 2x3 TDFN

Timekeeping Features

• Real-Time Clock/Calendar (RTCC):

- Hours, minutes, seconds, day of week, day,

month, year

- Leap year compensated to 2399

- 12/24-hour modes

• Oscillator for 32.768 kHz Crystals:

- Optimized for 6-9 pF crystals

• 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 Timestamp:

- Time logged on switchover to and from Battery

mode

Low-Power Features

• Wide Voltage Range:

- Operating voltage range of 1.8V to 5.5V

- Backup voltage range of 1.3V to 5.5V

• Low Typical Timekeeping Current:

- Operating from VCC: 1.2 µA at 3.3V

- Operating from VBAT: 925 nA at 3.0V

• Automatic Switchover to Battery Backup

User Memory

• 64-Byte Battery-Backed SRAM

• 1 Kbit EEPROM Memory:

- Software write-protect

- Page write up to eight bytes

- Endurance: 1M Erase/Write cycles

• 64-Bit Protected EEPROM Area:

- Robust write unlock sequence

- EUI-48™ MAC address (MCP79411)

- EUI-64™ MAC address (MCP79412)