MCP7940N_14 Datasheet, PDF (1/56 Pages) Microchip Technology – Clock output with selectable frequency

MCP7940N
Battery-Backed I²C™ Real-Time Clock/Calendar with SRAM
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 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
Operating Ranges:
• 2-Wire Serial Interface, I²C™ Compatible
- I²C clock rate up to 400 kHz
• Temperature Range:
- Industrial (I): -40°C to +85°C
- Extended (E): -40°C to +125°C
Packages:
• 8-Lead SOIC, MSOP, TSSOP, PDIP and 2x3
TDFN
General Description:
The MCP7940N 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
MCP7940N 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 MCP7940N 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.
Package Types
SOIC, MSOP, TSSOP⁽¹⁾, PDIP⁽¹⁾
X1 1
X2 2
V_BAT
3
VSS 4
8 VCC
7 MFP
6 SCL
5 SDA
TDFN⁽¹⁾
X1 1
X2 2
VBAT 3
VSS 4
8 VCC
7 MFP
6 SCL
5 SDA
Note 1: Available in I-temp only.
 2010-2014 Microchip Technology Inc.
DS20005010F-page 1