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  • The M41T94 is a serial real-time clock with 44 bytes of NVRAM and a RESET output. A built-in 32,768 Hz oscillator (external crystal controlled) and 8 bytes of the SRAM (see Table 4 on page 18) are used for the clock/calendar function and are configured in binary coded decimal (BCD) format.

    An additional 12 bytes of RAM provide status/control of alarm, watchdog and square wave functions. Addresses and data are transferred serially via a serial SPI interface. The built-in address register is incremented automatically after each WRITE or READ data byte. The M41T94 has a built-in power sense circuit which detects power failures and automatically switches to the battery supply when a power failure occurs. The energy needed to sustain the SRAM and clock operations can be supplied by a small lithium button-cell supply when a power failure occurs. Functions available to the user include a non-volatile, time-of-day clock/calendar, alarm interrupts, watchdog timer and programmable square wave output. Other features include a power-on reset as well as two additional debounced inputs (RSTIN1and RSTIN2) which can also generate an output reset (RST). 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 - valid until year 2100), 30 and 31 day months are made automatically. The ninth clock address location controls user access to the clock information and also stores the clock software calibration setting.
    The M41T94 is supplied in either a 16-lead plastic SOIC (requiring user supplied crystal and battery) or a 28-lead SOIC SNAPHAT®package (which integrates both crystal and battery in a single SNAPHAT top). The 28-pin, 330 mil SOIC provides sockets with gold plated contacts at both ends for direct connection to a separate SNAPHAT housing containing the battery and crystal. The unique design allows the SNAPHAT battery/crystal package to be mounted on top of the SOIC package after the completion of the surface mount process.
    Insertion of the SNAPHAT housing after reflow prevents potential battery and crystal damage due to the high temperatures required for device surface-mounting. The SNAPHAT housing is also keyed to prevent reverse insertion.
    The SOIC and battery/crystal packages are shipped separately in plastic anti-static tubes or in tape & reel form. For the 28-lead SOIC, the battery/crystal package (e.g., SNAPHAT) part number is “M4TXX-BR12SH”.

    Key Features

    • Counters for tenths/hundredths of seconds, seconds, minutes, hours, day, date, month, year, and century
    • 32 KHz crystal oscillator integrating load capacitance (12.5 pF) providing exceptional oscillator stability and high crystal series resistance operation
    • Serial peripheral interface (2 MHz SPI)
    • Ultralow battery supply current of 500 nA (max)
    • 2.7 to 5.5 V operating voltage
    • 2.5 to 5.5 V oscillator operating voltage
    • Battery low flag
    • Automatic switchover and deselect circuitry
    • 44 bytes of general purpose RAM
    • Programmable alarm and interrupt function (valid even during battery backup mode)
    • Accurate programmable watchdog timer (from 62.5 ms to 128 s)
    • Microprocessor power-on reset
    • Choice of power-fail deselect voltages (VCC= 2.7 to 5.5 V):
      • THS = VSS; 2.55 V ≤ VPFD≤ 2.70 V
      • THS = VCC; 4.20 V ≤ VPFD≤ 4.50 V
    • Packaging includes a 28-lead SOIC and SNAPHAT®top (to be ordered separately) or 16-lead SOIC
    • 28-lead SOIC package provides direct connection for a SNAPHAT®top which contains the battery and crystal
    • RoHS compliant
      • Lead-free second level interconnect

Circuit Diagram

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STMicroelectronics - M41T94

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Quality and Reliability

Part Number Marketing Status Package Grade RoHS Compliance Grade Material Declaration**
M41T94MH6F
Active
SO-28 Industrial Ecopack1
M41T94MQ6F
Active
SO-16 Industrial Ecopack1 (*)

M41T94MH6F

Package:

SO-28

Material Declaration**:

PDF XML

Marketing Status

Active

Package

SO-28

Grade

Industrial

RoHS Compliance Grade

Ecopack1

M41T94MQ6F

Package:

SO-16

Material Declaration**:

PDF XML

Marketing Status

Active

Package

SO-16

Grade

Industrial

RoHS Compliance Grade

Ecopack1 (*)

(**) 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

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ECCN (US)
ECCN (EU)
Packing Type
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Temperature (°C) Budgetary Price (US$)*/Qty
More info
min
max
M41T94MH6F Available at 8 distributors

Distributor availability ofM41T94MH6F

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 2072 1 Order Now
RS COMPONENTS EUROPE 3036 1 Order Now
AVNET AMERICA 5616 0 Order Now
FUTURE WORLDWIDE 2808 936 Order Now
ARROW EUROPE 6146 0 Order Now
ARROW AMERICA 4680 936 Order Now
MOUSER WORLDWIDE 1153 1 Order Now
Farnell Element14 EUROPE 669 1 Order Now

Distributor reported inventory date: 2020-10-28

Distributor Name

DIGIKEY

Stock

2072

Min.Order

1

Region

WORLDWIDE Order Now

RS COMPONENTS

Stock

3036

Min.Order

1

Region

EUROPE Order Now

AVNET

Stock

5616

Min.Order

0

Region

AMERICA Order Now

FUTURE

Stock

2808

Min.Order

936

Region

WORLDWIDE Order Now

ARROW

Stock

6146

Min.Order

0

Region

EUROPE Order Now

ARROW

Stock

4680

Min.Order

936

Region

AMERICA Order Now

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Stock

1153

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

669

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2020-10-28

Free Sample Buy Direct
Active
EAR99 NEC Tape And Reel SO-28 -40 85 2.823 / 1k
MORE INFO

NVRAM size (B):

44

Country of Origin:

MALAYSIA

M41T94MQ6F Available at 11 distributors

Distributor availability ofM41T94MQ6F

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 7468 1 Order Now
COMPEL EUROPE 28 1 Order Now
RS COMPONENTS EUROPE 3430 1 Order Now
AVNET AMERICA 16000 0 Order Now
FUTURE WORLDWIDE 32500 2500 Order Now
ARROW EUROPE 2503 0 Order Now
Newark Element14 AMERICA 110 0 Order Now
ARROW AMERICA 2500 2500 Order Now
MOUSER WORLDWIDE 4006 1 Order Now
Farnell Element14 EUROPE 2172 1 Order Now
ANGLIA Live EUROPE 1681 1 Order Now

Distributor reported inventory date: 2020-10-28

Distributor Name

DIGIKEY

Stock

7468

Min.Order

1

Region

WORLDWIDE Order Now

COMPEL

Stock

28

Min.Order

1

Region

EUROPE Order Now

RS COMPONENTS

Stock

3430

Min.Order

1

Region

EUROPE Order Now

AVNET

Stock

16000

Min.Order

0

Region

AMERICA Order Now

FUTURE

Stock

32500

Min.Order

2500

Region

WORLDWIDE Order Now

ARROW

Stock

2503

Min.Order

0

Region

EUROPE Order Now

Newark Element14

Stock

110

Min.Order

0

Region

AMERICA Order Now

ARROW

Stock

2500

Min.Order

2500

Region

AMERICA Order Now

MOUSER

Stock

4006

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

2172

Min.Order

1

Region

EUROPE Order Now

ANGLIA Live

Stock

1681

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2020-10-28

Free Sample Buy Direct
Active
EAR99 NEC Tape And Reel SO-16 -40 85 1.705 / 1k
MORE INFO

NVRAM size (B):

44

Country of Origin:

MOROCCO

M41T94MH6F

Marketing Status

Active

ECCN (US)

EAR99

Budgetary Price (US$)*/Qty

2.823 / 1k

Distributor availability ofM41T94MH6F

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 2072 1 Order Now
RS COMPONENTS EUROPE 3036 1 Order Now
AVNET AMERICA 5616 0 Order Now
FUTURE WORLDWIDE 2808 936 Order Now
ARROW EUROPE 6146 0 Order Now
ARROW AMERICA 4680 936 Order Now
MOUSER WORLDWIDE 1153 1 Order Now
Farnell Element14 EUROPE 669 1 Order Now

Distributor reported inventory date: 2020-10-28

Distributor Name

DIGIKEY

Stock

2072

Min.Order

1

Region

WORLDWIDE Order Now

RS COMPONENTS

Stock

3036

Min.Order

1

Region

EUROPE Order Now

AVNET

Stock

5616

Min.Order

0

Region

AMERICA Order Now

FUTURE

Stock

2808

Min.Order

936

Region

WORLDWIDE Order Now

ARROW

Stock

6146

Min.Order

0

Region

EUROPE Order Now

ARROW

Stock

4680

Min.Order

936

Region

AMERICA Order Now

MOUSER

Stock

1153

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

669

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2020-10-28

ECCN (EU)

NEC

Packing Type

Tape And Reel

Package

SO-28

Operating Temperature (°C)

(min)

-40

(max)

85

Budgetary Price (US$)* / Qty

2.823 / 1k

NVRAM size (B)

44

Country of Origin

MALAYSIA

M41T94MQ6F

Marketing Status

Active

ECCN (US)

EAR99

Budgetary Price (US$)*/Qty

1.705 / 1k

Distributor availability ofM41T94MQ6F

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 7468 1 Order Now
COMPEL EUROPE 28 1 Order Now
RS COMPONENTS EUROPE 3430 1 Order Now
AVNET AMERICA 16000 0 Order Now
FUTURE WORLDWIDE 32500 2500 Order Now
ARROW EUROPE 2503 0 Order Now
Newark Element14 AMERICA 110 0 Order Now
ARROW AMERICA 2500 2500 Order Now
MOUSER WORLDWIDE 4006 1 Order Now
Farnell Element14 EUROPE 2172 1 Order Now
ANGLIA Live EUROPE 1681 1 Order Now

Distributor reported inventory date: 2020-10-28

Distributor Name

DIGIKEY

Stock

7468

Min.Order

1

Region

WORLDWIDE Order Now

COMPEL

Stock

28

Min.Order

1

Region

EUROPE Order Now

RS COMPONENTS

Stock

3430

Min.Order

1

Region

EUROPE Order Now

AVNET

Stock

16000

Min.Order

0

Region

AMERICA Order Now

FUTURE

Stock

32500

Min.Order

2500

Region

WORLDWIDE Order Now

ARROW

Stock

2503

Min.Order

0

Region

EUROPE Order Now

Newark Element14

Stock

110

Min.Order

0

Region

AMERICA Order Now

ARROW

Stock

2500

Min.Order

2500

Region

AMERICA Order Now

MOUSER

Stock

4006

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

2172

Min.Order

1

Region

EUROPE Order Now

ANGLIA Live

Stock

1681

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2020-10-28

ECCN (EU)

NEC

Packing Type

Tape And Reel

Package

SO-16

Operating Temperature (°C)

(min)

-40

(max)

85

Budgetary Price (US$)* / Qty

1.705 / 1k

NVRAM size (B)

44

Country of Origin

MOROCCO

(*) 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