Overview
The M41ST87WSS6F is a secure serial real-time clock (RTC) and NVRAM supervisor produced by STMicroelectronics. This component is designed to provide a low-power, 1280-bit static CMOS SRAM, organized as 160 bytes by 8 bits. It features a built-in 32.768 kHz oscillator and supports various functions such as a non-volatile time-of-day clock/calendar, alarm interrupts, tamper detection, watchdog timer, and programmable square wave output. The device is suitable for applications requiring precise timekeeping and data storage, even in the event of power failures, thanks to its automatic switchover to a battery supply.
Key Specifications
| Parameter | Value |
|---|---|
| Operating Voltage | 2.7 to 3.6 V |
| I2C Bus Frequency | 400 kHz |
| Oscillator Operating Voltage | 2.5 to 5.5 V |
| NVRAM Size | 128 bytes |
| Power-Fail Deselect Voltage | Approx. 2.9 V (THS = 1), Approx. 2.63 V (THS = 0) |
| Package Type | SSOP 20 (7.2x5.3 mm) |
| Operating Temperature | -40°C to 85°C |
| Battery Supply Current | Typically 500 nA |
Key Features
- Low power 1280-bit static CMOS SRAM organized as 160 bytes by 8 bits
- Built-in 32.768 kHz oscillator (internal crystal-controlled)
- Non-volatile time-of-day clock/calendar with automatic corrections for month lengths and leap years
- Alarm interrupts, tamper detection, and watchdog timer
- Programmable square wave output
- Automatic switchover to battery supply during power failures
- Two independent power-fail comparators (1.25 V reference)
- Unique electronic serial number (8-byte)
- Microprocessor power-on reset output and battery low flag
- Security features including tamper indication circuits and LPSRAM clear function
Applications
- Embedded systems requiring precise timekeeping and data storage
- Industrial control systems
- Medical devices
- Automotive systems
- Security and surveillance systems
- Any application needing a reliable RTC with NVRAM and security features
Q & A
- What is the primary function of the M41ST87WSS6F?
The primary function of the M41ST87WSS6F is to provide a secure serial real-time clock (RTC) and NVRAM supervisor.
- What is the operating voltage range of the M41ST87WSS6F?
The operating voltage range is 2.7 to 3.6 V.
- What type of interface does the M41ST87WSS6F use?
The device uses a two-line, bidirectional I2C interface.
- How much NVRAM does the M41ST87WSS6F provide?
The device provides 128 bytes of clearable, general-purpose NVRAM.
- What security features does the M41ST87WSS6F include?
The device includes tamper indication circuits with timestamp and RAM clear, and an LPSRAM clear function.
- How does the M41ST87WSS6F handle power failures?
The device automatically switches to a battery supply during power failures and has a built-in power sense circuit.
- What is the typical battery supply current of the M41ST87WSS6F?
The typical battery supply current is 500 nA.
- What are the packaging options for the M41ST87WSS6F?
The device is available in a 20-lead SSOP package.
- What is the operating temperature range of the M41ST87WSS6F?
The operating temperature range is -40°C to 85°C.
- Does the M41ST87WSS6F have a unique electronic serial number?
Yes, the device includes a unique 8-byte electronic serial number.
