M41ST87W:5.0 V, 3.3/3.0 V secure real-time clock , NVRAM supervisor with tamper detection and 128 bytes of clearable NVRAM

The M41ST87Y/W secure serial RTC and NVRAM supervisor is a low power 1280-bit, static CMOS SRAM organized as 160 bytes by 8 bits. A built-in 32.768 kHz oscillator (internal crystal-controlled) and 8 bytes of the SRAM are used for the clock/calendar function and are configured in binary coded decimal (BCD) format.

An additional 11 bytes of RAM provide calibration, status/control of alarm, watchdog, tamper, and square wave functions. 8 bytes of ROM and finally 128 bytes of user RAM are also provided. 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 M41ST87Y/W 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, tamper detection, 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), 30 and 31 day months are made automatically.

Key Features

  • 5.0, 3.3, or 3.0 V operation
  • 400 kHz I2 C bus
  • NVRAM supervisor to non-volatize external LPSRAM
  • 2.5 to 5.5 V oscillator operating voltage
  • Automatic switchover and deselect circuitry
  • Choice of power-fail deselect voltages
    • M41ST87Y: (not recommended for new design, contact ST sales office for availability) THS = 1: VPFD ≈ 4.63 V; VCC = 4.75 to 5.5 V THS = 0: VPFD ≈ 4.37 V; VCC = 4.5 to 5.5 V
    • M41ST87W: THS = 1: VPFD ≈ 2.9 V; VCC = 3.0 to 3.6 V THS = 0: VPFD ≈ 2.63 V; VCC = 2.7 to 3.6 V
  • Two independent power-fail comparators (1.25 V reference)
  • Counters for tenths/hundredths of seconds, seconds, minutes, hours, day, date, month, year, and century
  • 128 bytes of clearable, general purpose NVRAM
  • Programmable alarm and interrupt function (valid even during battery backup mode)
  • Programmable watchdog timer
  • Unique electronic serial number (8-byte)
  • 32 kHz frequency output available upon power-on
  • Microprocessor power-on reset output
  • Battery low flag
  • Ultra-low battery supply current of 500 nA (typ)
  • Security features
    • Tamper indication circuits with timestamp and RAM clear
    • LPSRAM clear function (TPCLR )
    • Packaging includes a 28-lead, embedded crystal SOIC and a 20-lead SSOP
    • Oscillator stop detection
产品规格
DescriptionVersionSize
DS3301: 5.0 V and 3.3/3.0 V secure serial RTC and NVRAM supervisor with tamper detection and 128 bytes of clearable NVRAM11.01 MB
应用手册
DescriptionVersionSize
AN3060: 串行实时时钟(RTC)应用指南3.0453 KB
AN1011: ST NVRAM 和实时时钟(RTC)产品中使用的电池技术4.0416 KB
AN1879: 如何使用M41ST87W的入侵检测及RAM清除功能5.0455 KB
AN934: How to use the digital calibration feature in TIMEKEEPER® and serial real-time clock (RTC) products4.1123 KB
AN1216: Implementing a periodic alarm with TIMEKEEPER® and serial real-time clocks (RTCs)2.0192 KB
AN4641: 集成TIMEKEEPER® 与实时时钟监控器功能1.0508 KB
AN923: Managing century information using serial real-time clocks and TIMEKEEPER® NVRAMs4.0142 KB
AN1572: 串行实时时钟(RTC)的掉电时间戳功能2.0394 KB
AN1336: Power-fail comparator for NVRAM supervisory devices2.0127 KB
AN1012: 预测NVRAM 和串行RTC 的电池寿命和数据保存期限4.1813 KB
HW Model & CAD Libraries
DescriptionVersionSize
Ibis model1.014 KB
手册
DescriptionVersionSize
Serial real-time clock ICs1.0827 KB
Clocks and Timers Software
型号制造商Description
STSW-SRTC001STI2C code for Serial RTC
STSW-SRTC002STSPI code -Serial RTC
样片和购买
型号PackagePacking TypeOperating Temperature (°C) (min)Operating Temperature (°C) (max)Unit Price (US$) *QuantityNVRAM size (B)ECCN (EU)ECCN (US)Country of Origin
M41ST87WMX6TRSO28 WITH EMBEDDED CRYSTALTape And Reel-40853.941000128NECEAR99MALAYSIA
M41ST87WSS6FSSOP 20 7.2x5.3Tape And Reel-40852.941000128NECEAR99MALAYSIA
质量和可靠性
型号PackageGradeRoHS Compliance GradeMaterial Declaration**
M41ST87WMX6TRSO28 WITH EMBEDDED CRYSTALIndustrialEcopack1md_l8-wspc-so28-wspc-.30-wspc-with-wspc-embedded-wspc-crystal_asl8-wspc-b6aa87w-wspc-(m41st87wmx6tr)-wspc-wcp-wspc-ver2_signed.pdf
md_l8-wspc-so28-wspc-.30-wspc-with-wspc-embedded-wspc-crystal_asl8-wspc-b6aa87w-wspc-(m41st87wmx6tr)-wspc-wcp-wspc-ver2.xml
M41ST87WSS6FSSOP 20 7.2x5.3IndustrialEcopack2md_s9-wspc-ssop-wspc-20-wspc-7.2x5.3_eass-wspc-d6aa87w-wspc-(m41st87wss6f)-wspc-wcp-wspc-ver2_signed.pdf
md_s9-wspc-ssop-wspc-20-wspc-7.2x5.3_eass-wspc-d6aa87w-wspc-(m41st87wss6f)-wspc-wcp-wspc-ver2.xml
5.0 V and 3.3/3.0 V secure serial RTC and NVRAM supervisor with tamper detection and 128 bytes of clearable NVRAM M41ST87W
circuit_diagram_9497_thumbnail.png M41ST87W
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
如何使用M41ST87W的入侵检测及RAM清除功能 M41ST87W
How to use the digital calibration feature in TIMEKEEPER® and serial real-time clock (RTC) products M41T60
Implementing a periodic alarm with TIMEKEEPER® and serial real-time clocks (RTCs) M41T94
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
Predicting the battery life and data retention period of NVRAMs and serial RTCs M41ST87W
Predicting the battery life and data retention period of NVRAMs and serial RTCs M4T28-BR12SH
md_l8-wspc-so28-wspc-.30-wspc-with-wspc-embedded-wspc-crystal_asl8-wspc-b6aa87w-wspc-(m41st87wmx6tr)-wspc-wcp-wspc-ver2.xml M41ST87W
md_s9-wspc-ssop-wspc-20-wspc-7.2x5.3_eass-wspc-d6aa87w-wspc-(m41st87wss6f)-wspc-wcp-wspc-ver2_signed.pdf M41ST87W
md_s9-wspc-ssop-wspc-20-wspc-7.2x5.3_eass-wspc-d6aa87w-wspc-(m41st87wss6f)-wspc-wcp-wspc-ver2.xml M41ST87W