M41T66

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Serial real-time clock (RTC) with alarm

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  • The M41T66 is a low-power serial real-time clock (RTC) with a built-in 32.768 kHz oscillator (external crystal controlled). Eight registers are used for the clock/calendar function and are configured in binary coded decimal (BCD) format. An additional 8 registers provide status/control of alarm, square wave, 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, programmable square wave output, and watchdog output. 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 M41T66 is supplied in a 16-pin QFN.

    Key Features

    • Counters for tenths/hundredths of seconds, seconds, minutes, hours, day, date, month, year, and century
    • 32 KHz crystal oscillator integrating load capacitance and high crystal series resistance operation
    • Oscillator stop detection monitors clock operation
    • Serial interface supports I2C bus (400 kHz)
    • 525 nA timekeeping current at 3 V
    • Low operating current of 35 μA (at 400 kHz)
    • Timekeeping down to 1.0 V
    • 1.3 V to 4.4 V I2C bus operating voltage
      • Allows use in lithium ion rechargeable applications
    • 32 KHz square wave on power-up to drive a microcontroller in low-power mode
    • Programmable (1 Hz to 32 KHz) square wave
    • Programmable alarm with interrupt function
    • Accurate programmable watchdog (from 62.5 ms to 31 min)
    • Software clock calibration to compensate deviation of crystal due to temperature
    • Automatic leap year compensation
    • Operating temperature of –40 to 85 °C
    • Lead-free 16-pin QFN package

Circuit Diagram

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STMicroelectronics - M41T66

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Quality and Reliability

Part Number Marketing Status Package Grade RoHS Compliance Grade Material Declaration**
M41T66Q6F
Active
QFN-16L Industrial Ecopack2

M41T66Q6F

Package:

QFN-16L

Material Declaration**:

PDF XML

Marketing Status

Active

Package

QFN-16L

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.

Sample & Buy

Part Number
Order from Distributors
Order from ST
Marketing Status
ECCN (US)
ECCN (EU)
Packing Type
Package
Temperature (°C) Budgetary Price (US$)*/Qty
More info
min
max
M41T66Q6F No availability of distributors reported, please contact our sales office Buy Direct
Active
EAR99 NEC Tape And Reel QFN-16L -40 85 0.823 / 1k
MORE INFO

NVRAM size (B):

-

Country of Origin:

MALAYSIA

M41T66Q6F

Marketing Status

Active

ECCN (US)

EAR99

Budgetary Price (US$)*/Qty

0.823 / 1k

ECCN (EU)

NEC

Packing Type

Tape And Reel

Package

QFN-16L

Operating Temperature (°C)

(min)

-40

(max)

85

Budgetary Price (US$)* / Qty

0.823 / 1k

NVRAM size (B)

-

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