MCP79400_16 Datasheet, PDF (1/62 Pages) Microchip Technology – Battery-Backed I2C Real-Time Clock/Calendar with SRAM and Protected EEPROM

MCP79400/MCP79401/MCP79402
Battery-Backed I²C Real-Time Clock/Calendar with
SRAM and Protected EEPROM
Device Selection Table
Part Number
MCP79400
MCP79401
MCP79402
Protected EEPROM
Unprogrammed
EUI-48^™
EUI-64^™
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
• 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 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 battery backup: 925 nA at
3.0V
• Automatic Switchover to Battery Backup
User Memory
• 64-Byte Battery-Backed SRAM
• 64-Bit Protected EEPROM Area:
- Robust write unlock sequence
- EUI-48^™ MAC address (MCP79401)
- EUI-64^™ MAC address (MCP79402)
- Custom programming 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
General Description
The MCP7940X 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
MCP7940X 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 MCP7940X 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
back-up 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 time-stamp.
The MCP7940X features 64 bits of EEPROM which is
only writable after an unlock sequence, making it ideal
for storing a unique ID or other critical information. The
MCP79401 and MCP79402 are pre-programmed with
EUI-48 and EUI-64 addresses, respectively. Custom
programming is also available.
Package Types
SOIC, TSSOP, MSOP
X1 1
X2 2
VBAT 3
VSS 4
8 VCC
7 MFP
6 SCL
5 SDA
TDFN
X1 1
X2 2
VBAT 3
VSS 4
8 VCC
7 MFP
6 SCL
5 SDA
 2011-2016 Microchip Technology Inc.
DS20005009F-page 1