M41T81SM6F Real-Time Clock (RTC) ICs by STMicroelectronics

Serial real-time clock (RTC) with alarm

Status: Active
Series: M41T81S
RoHS: Compliant
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The M41T81S is a low-power serial real-time clock (RTC) with a built-in 32.768 kHz oscillator (external crystal controlled). Eight bytes of the SRAM are used for the clock/calendar function and are configured in binary-coded decimal (BCD) format. An additional 12 bytes of SRAM provide status/control of alarm, watchdog and square wave functions. Addresses and data are transferred serially via a two line, bidirectional I 2 C interface. The built-in address register is incremented automatically after each WRITE or READ data byte. The M41T81S 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 clock operations can be supplied by a small lithium button 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. 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 M41T81S is supplied in either an 8-pin SOIC or an 18-pin 300 mil SOIC package which includes an embedded 32 KHz crystal. The 18-pin, embedded crystal SOIC requires only a user-supplied battery to provide non-volatile operation.

Prices starting from US$1.11


Distributor Starting From Stock
Logo for Future Electronics Future Electronics US$1.57
37,500
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Logo for Newark Electronics Newark Electronics US$1.85
2,500
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Logo for Avnet America Avnet America US$1.71
2,500
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Logo for Farnell Farnell US$1.11
-
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Logo for EBV Elektronik EBV Elektronik -
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Features

Counters for tenths/hundredths of seconds, seconds, minutes, hours, day, date, month, year, and century
32 KHz crystal oscillator with integrated load capacitance (12.5 pf) which provides exceptional oscillator stability and high crystal series resistance operation)
Oscillator stop detection (monitors clock operation)
Serial interface supports I2C bus (400 kHz protocol)
Ultra-low battery supply current of 0.6 μA (typ)
2.0 to 5.5 V clock operating voltage
Automatic switchover and deselect circuitry (fixed reference) which provides full operation in 3.0 V applications)
VCC= 2.7 to 5.5 V
2.5 V ≤ VPFD≤ 2.7 V
Power-down time-stamp (HT bit) which allows determination of time elapsed in battery backup
Battery low flag
Programmable alarm and interrupt function (valid even during battery backup mode)
Accurate programmable watchdog timer (from 62.5 ms to 128 s)
Software clock calibration (to compensate for crystal deviation due to temperature)
Operating temperature of –40 to 85 °C
Package options include an 8-lead SOIC or 18-lead embedded crystal SOIC

Resources




Alternative Descriptions

M41T81S Series 5.5 V I2C / 2-Wire / Serial SMT Real Time Clock - SOIC-8 | Future Electronics
Serial Real-Time Clock, Alarms SOIC8 | RS
Power Management Rohs Compliant: Yes |Stmicroelectronics M41T81SM6F | Newark Electronics
Real Time Clock Serial I2C 20Bytes 8-Pin SOIC T/R | Avnet America
IC, RTC, I2C, W/ ALARM, 8-SO | Farnell


Frequently Asked Questions

Where can I find additional details, specifications and documents for a M41T81SM6F?

Additional datasheets, footprints and schematics for M41T81SM6F are listed on our Part Details page. You can also find images and similar parts to M41T81SM6F on this page.

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Distributor pricing and stock information is available for M41T81SM6F on our Product Comparison page. Access via the 'View Pricing & Stock' button to view M41T81SM6F price breaks, MOQs, lead times, inventory and SKUs from distributors.

What category does M41T81SM6F fall under?

The M41T81SM6F is listed under Clocks and Timers > Real-Time Clock (RTC) ICs > RTC - Serial Interface.

Can I view similar or alternative parts?

You can view similar parts to M41T81SM6F when available in the RTC - Serial Interface range under the specifications section at the bottom of the details page.

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Submit any questions directly to the customer support team of the distributor listing the product. For the M41T81SM6F you can contact the distributor directly for product support, shipping queries etc.

Is the M41T81SM6F RoHS compliant?

Yes. This part has been flagged as RoHS Compliant by STMicroelectronics.

Which authorised distributors for M41T81SM6F have stock available?

Authorised distributors including Future Electronics, RS, Newark Electronics, Avnet America and Farnell have stock available or on a lead time for M41T81SM6F.

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