M41T56:Serial real-time clock (RTC) with 56 bytes NVRAM

The M41T56 is a low-power, serial real-time clock (RTC) with 56 bytes of NVRAM. A built-in 32,768 Hz oscillator (external crystal controlled) and the first 8 bytes of the RAM are used for the clock/calendar function and are configured in binary coded decimal (BCD) format. Addresses and data are transferred serially via a two-line, bidirectional bus. The built-in address register is incremented automatically after each WRITE or READ data byte.

The M41T56 clock has a built-in power sense circuit which detects power failures and automatically switches to the battery supply during power failures. The energy needed to sustain the RAM and clock operations can be supplied from a small lithium coin cell.

Typical data retention time is in excess of 10 years with a 50 mAh, 3 V lithium cell. The M41T56 is supplied in an 8-lead plastic SOIC package.

Key Features

  • Counters for seconds, minutes, hours, day, date, month, years, and century
  • 32 KHz crystal oscillator integrating load capacitance (12.5 pF) providing exceptional oscillator stability and high crystal series resistance operation
  • Serial interface supports I2 C bus (100 kHz protocol)
  • Ultra-low battery supply current of 450 nA (typ at 3 V)
  • 5 V ±10% supply voltage
  • Timekeeping down to 2.5 V
  • Automatic power-fail detect and switch circuitry
  • 56 bytes of general purpose RAM
  • Software clock calibration to compensate crystal deviation due to temperature
  • Automatic leap year compensation
  • Operating temperature of –40 °C to 85 °C
  • Available in an 8-lead, 150-mil, plastic SOIC (SO8)
  • RoHS compliant
    • Lead-free second level interconnect
Product Specifications
DescriptionVersionSize
DS1449: Serial real-time clock (RTC) with 56 bytes NVRAM9.1478 KB
Application Notes
DescriptionVersionSize
AN3060: Applications guide for serial real-time clocks (RTCs)3.0878 KB
AN1011: Battery technology used in NVRAM and real-time clock (RTC) products from ST4.0248 KB
AN934: How to use the digital calibration feature in TIMEKEEPER® and serial real-time clock (RTC) products4.1123 KB
AN4641: Integrating TIMEKEEPER® and real-time clock supervisor functions1.0479 KB
AN923: Managing century information using serial real-time clocks and TIMEKEEPER® NVRAMs4.0142 KB
AN1572: Power-down time-stamp function in serial real-time clocks (RTCs)2.0171 KB
AN1336: Power-fail comparator for NVRAM supervisory devices2.0127 KB
AN1012: Predicting the battery life and data retention period of NVRAMs and serial RTCs4.1439 KB
AN922: Using a Super Cap to back up the M41T56, M41T00, M41T11, M41T81, M41T94, and M41ST84W (16-pin)2.184 KB
HW Model & CAD Libraries
DescriptionVersionSize
Ibis model1.08 KB
Brochures
DescriptionVersionSize
Serial real-time clock ICs1.0827 KB
Smart grid distribution and smart meters - Energy-efficient solutions2.01 MB
Product Certifications
DescriptionVersionSize
Products Underwriter Laboratories (UL) Information2.1543 KB
Clocks and Timers Software
Part NumberManufacturerDescription
STSW-SRTC001STI2C code for Serial RTC
STSW-SRTC002STSPI code -Serial RTC
Sample & Buy
Part NumberPackagePacking TypeOperating Temperature (°C) (min)Operating Temperature (°C) (max)Unit Price (US$) *QuantityNVRAM size (B)ECCN (EU)ECCN (US)Country of Origin
M41T56M6FSO-8Tape And Reel-40851.199100056NECEAR99MOROCCO
Quality & Reliability
Part NumberPackageGradeRoHS Compliance GradeMaterial Declaration**
M41T56M6FSO-8IndustrialEcopack1md_o7-wspc-so-wspc-08-wspc-.15-wspc-jedec_bazmg6aat56.pdf
md_o7-wspc-so-wspc-08-wspc-.xml
Serial real-time clock (RTC) with 56 bytes NVRAM M41T56
circuit_diagram_6104_thumbnail.png M41T56
串行实时时钟(RTC)应用指南 M41T60
ST NVRAM 和实时时钟(RTC)产品中使用的电池技术 M4Z28-BR00SH
How to use the digital calibration feature in TIMEKEEPER® and serial real-time clock (RTC) products M41T60
集成TIMEKEEPER® 与实时时钟监控器功能 M41T60
Managing century information using serial real-time clocks and TIMEKEEPER® NVRAMs M41T60
串行实时时钟(RTC)的掉电时间戳功能 M41T60
Power-fail comparator for NVRAM supervisory devices M41T60
预测NVRAM 和串行RTC 的电池寿命和数据保存期限 M4Z28-BR00SH
使用Super Cap 为M41T56、M41T00、M41T11、M41T81、M41T94 和M41ST84W (16 引脚)提供备用电源 M41T94
Using a Super Cap to back up the M41T56, M41T00, M41T11, M41T81, M41T94, and M41ST84W (16-pin) M41T81
Predicting the battery life and data retention period of NVRAMs and serial RTCs M4T28-BR12SH
STEVAL-ISA062V1: 6 W, wide-range dual and single output SMPS demonstration board based on the VIPer17 STEVAL-ISA062V1
Predicting the battery life and data retention period of NVRAMs and serial RTCs M4Z28-BR00SH
md_o7-wspc-so-wspc-08-wspc-.15-wspc-jedec_bazmg6aat56.pdf M41T56
md_o7-wspc-so-wspc-08-wspc-.xml TS4871