Low-power serial real-time clock (RTC) with alarm

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  • The M41T6x is a low-power serial real-time clock (RTC) with a built-in 32.768 kHz oscillator. Eight registers are used for the clock/calendar function and are configured in binary-coded decimal (BCD) format. An additional eight registers provide status/control of alarm, 32 kHz output, calibration, and watchdog functions. Addresses and data are transferred serially via a two-line, bidirectional I²C interface. The built-in address register is incremented automatically after each WRITE or READ data byte.

    Functions available to the user include a time-of-day clock/calendar, alarm interrupts (M41T62/65), 32 kHz output (M41T62/64), programmable square wave output (M41T62/64), and watchdog output (M41T65). The eight clock address locations contain the century, year, month, date, day, hour, minute, second and tenths/hundredths of a second in 24-hour BCD format. Corrections for 28-, 29- (leap year), 30- and 31-day months are made automatically.
    The M41T6x is supplied in two very small packages: a tiny, 3 x 3 mm 16-pin QFN which requires a user-supplied 32 kHz crystal, and an ultra-small 1.5 x 3.2 mm LCC with embedded crystal - no external crystal is required.

    Key Features

    • Serial real-time clock (RTC) with alarm functions
      • 400 kHz I²C serial interface
      • Memory mapped registers for seconds, minutes, hours, day, date, month, year, and century
      • Tenths/hundredths of seconds register
    • 350 nA timekeeping current at 3 V
    • Timekeeping down to 1.0 V
    • 1.3 V to 4.4 V I²C bus operating voltage
      • 4.4 V max VCCsuitable for lithium-ion battery operation
    • Low operating current of 35 μA (at 400 kHz I²C speed)
    • 32 kHz square wave output is on at power-up. Suitable for driving a microcontroller in low-power mode. Can be disabled. (M41T62/64)
    • Programmable 1 Hz to 32 kHz square wave output (M41T62/64)
    • Programmable alarm with interrupt function (M41T62/65)
    • 32 kHz crystal oscillator integrates crystal load capacitors, works with high series resistance crystals
    • Oscillator stop detection monitors clock operation
    • Accurate programmable watchdog
      • 62.5 ms to 31 minutes timeout
    • Software clock calibration. Can adjust timekeeping to within ±2 parts per million (±5 seconds per month)
    • Automatic leap year compensation
    • –40 to +85 °C operation
    • Two package options:
      • Very small 3 x 3 mm, lead-free and halogen-free (ECOPACK2) 16-lead QFN
      • Ultra-small 1.5 x 3.2 mm, lead-free and halogen-free (ECOPACK2) 8-pin ceramic leadless chip carrier with embedded 32 kHz crystal - no external oscillator components required (M41T62)

Circuit Diagram

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Part Number
Package
Packing Type
Temperature (°C) Marketing Status
Budgetary Price (US$)*
Quantity
NVRAM size (B)
More info
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min
max
M41T64Q6F VFQFPN 16 3x3x0.9 Tape And Reel -40 85
Active
0.823 10000 -
MORE INFO

ECCN (US):

EAR99

Country of Origin:

MALAYSIA

Check Availability

Distributor availability ofM41T64Q6F

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 1824 1 Order Now
MOUSER WORLDWIDE 1259 1 Order Now

Distributor reported inventory date: 2019-11-26

Distributor Name

DIGIKEY

Stock

1824

Min.Order

1

Region

WORLDWIDE Order Now

MOUSER

Stock

1259

Min.Order

1

Region

WORLDWIDE Order Now

Distributor reported inventory date: 2019-11-26

Buy now

M41T64Q6F

Package

VFQFPN 16 3x3x0.9

Packing Type

Tape And Reel

Unit Price (US$)

0.823*

Distributor availability ofM41T64Q6F

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 1824 1 Order Now
MOUSER WORLDWIDE 1259 1 Order Now

Distributor reported inventory date: 2019-11-26

Distributor Name

DIGIKEY

Stock

1824

Min.Order

1

Region

WORLDWIDE Order Now

MOUSER

Stock

1259

Min.Order

1

Region

WORLDWIDE Order Now

Distributor reported inventory date: 2019-11-26

Operating Temperature (°C)

(min)

-40

(max)

85

Marketing Status

Active

Unit Price (US$)

0.823

Quantity

10000

NVRAM size (B)

-

ECCN (US)

EAR99

Country of Origin

MALAYSIA

(*) Suggested Resale Price per unit (USD) for BUDGETARY USE ONLY. For quotes, prices in local currency, please contact your local ST Sales Office  or our Distributors

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Embedded Software

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Technical Documentation

    • Description Version Size Action
      DS3840
      Low-power serial real-time clocks (RTCs) with alarm
      24.0
      700.13 KB
      PDF
      DS3840

      Low-power serial real-time clocks (RTCs) with alarm

    • Description Version Size Action
      AN3060
      Applications guide for serial real-time clocks (RTCs)
      3.0
      878.56 KB
      PDF
      AN1011
      Battery technology used in NVRAM and real-time clock (RTC) products from ST
      4.0
      248.17 KB
      PDF
      AN934
      How to use the digital calibration feature in TIMEKEEPER® and serial real-time clock (RTC) products
      4.1
      123.42 KB
      PDF
      AN1216
      Implementing a periodic alarm with TIMEKEEPER® and serial real-time clocks (RTCs)
      2.0
      192.89 KB
      PDF
      AN4641
      Integrating TIMEKEEPER® and real-time clock supervisor functions
      1.0
      479.28 KB
      PDF
      AN923
      Managing century information using serial real-time clocks and TIMEKEEPER® NVRAMs
      4.0
      142.23 KB
      PDF
      AN1572
      Power-down time-stamp function in serial real-time clocks (RTCs)
      2.0
      171.31 KB
      PDF
      AN1336
      Power-fail comparator for NVRAM supervisory devices
      2.0
      127.81 KB
      PDF
      AN3060

      Applications guide for serial real-time clocks (RTCs)

      AN1011

      Battery technology used in NVRAM and real-time clock (RTC) products from ST

      AN934

      How to use the digital calibration feature in TIMEKEEPER® and serial real-time clock (RTC) products

      AN1216

      Implementing a periodic alarm with TIMEKEEPER® and serial real-time clocks (RTCs)

      AN4641

      Integrating TIMEKEEPER® and real-time clock supervisor functions

      AN923

      Managing century information using serial real-time clocks and TIMEKEEPER® NVRAMs

      AN1572

      Power-down time-stamp function in serial real-time clocks (RTCs)

      AN1336

      Power-fail comparator for NVRAM supervisory devices

Publications and Collaterals

    • Description Version Size Action
      Serial real-time clock ICs 1.0
      827.11 KB
      PDF

      Serial real-time clock ICs

Part Number Marketing Status Package Grade RoHS Compliance Grade Material Declaration**
M41T64Q6F
Active
VFQFPN 16 3x3x0.9 Industrial Ecopack2

M41T64Q6F

Package:

VFQFPN 16 3x3x0.9

Material Declaration**:

Marketing Status

Active

Package

VFQFPN 16 3x3x0.9

Grade

Industrial

RoHS Compliance Grade

Ecopack2

(**) The Material Declaration forms available on st.com may be generic documents based on the most commonly used package within a package family. For this reason, they may not be 100% accurate for a specific device. Please contact our sales support for information on specific devices.

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