Real Time Clock Chip M41T81SM6F YY-MM-DD-dd 2.7V to 5.5V SOIC-8

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

Description

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 I2C 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-ofday 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 nonvolatile operation.

Figure 1. Logic diagram

Specifications

Trading Guides

Shenzhen Retechip® Electronic Technology Co., Ltd. was established in 2013, specializing in electronic components distribution business.The products are widely used in communication equipment, power supply, medical electronics, automotive electronics, digital electronics, industrial electronics, display modules, intelligent electronics, new energy, the Internet of things, 5G productsand other fields，With high-quality products, reasonable prices, rapid distributionand timely service, we can provide customers with the most cost-effective products and save customers a lot of time.