Product overview
Description
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.
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All 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 | NRND | QFN-16L | Industrial | 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) | NVRAM size (B) | Country of Origin | Budgetary Price (US$)*/Qty | More info | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| min | max | |||||||||||||
| M41T66Q6F | No availability of distributors reported, please contact our sales office | NRND | EAR99 | NEC | Tape And Reel | QFN-16L | -40 | 85 | - | MALAYSIA | 0.823 / 1k | |||
Marketing Status
NRNDECCN (US)
EAR99Budgetary Price (US$)*/Qty
0.823 / 1k(*) Suggested Resale Price (USD) per defined quantity for BUDGETARY USE ONLY. For quotes, prices in local currency, please contact your local ST Sales Office or our Distributors
