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STMicroelectronics M41T82SM6E
- Part No.:
- M41T82SM6E
- Manufacturer:
- STMicroelectronics
- Category:
- Real Time Clocks
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
M41T82SM6E.pdf
- Description:
- IC RTC CLK/CALENDAR I2C 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,227
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Product details
Overview
M41T82SM6E from STMicroelectronics is an I²C real-time clock (RTC) IC in 8-lead SOIC package, providing battery-backed timekeeping with ±5 ppm factory calibration, ultra-low 365 nA battery current, and automatic VCC-to-battery switchover. It supports full BCD calendar (century, year, month, date, day, hour, minute, second, tenths/hundredths), programmable alarm interrupt, and operates from 2.0 V to 5.5 V - deployed in industrial control panels requiring long-term timestamp integrity during main power loss.
For engineers reviewing the M41T82SM6E datasheet, M41T82SM6E pinout, M41T82SM6E application, or M41T82SM6E equivalent, key selection criteria include its SO8 footprint compatibility, FT/RST open-drain reset output, absence of square-wave output (vs. M41T83), and reliance on external 32.768 kHz crystal for oscillator function.
Technical Context
The M41T82SM6E implements a slave-mode I²C interface (400 kHz max) with fixed 7-bit address 0xD0h and auto-incrementing register pointer. Its timekeeping engine uses a 32.768 kHz external crystal connected across XI/XO pins, with oscillator stop detection and halt-bit (HT) control for precise power-down timestamping.
Power management includes dual-threshold voltage sensing (VSO = VRST = 2.93 V typical) for seamless battery switchover and power-on reset generation. The device integrates 7 bytes of battery-backed SRAM, alarm masking logic, and write-protect functionality via software and hardware (WP pin not present; protection enabled via register bit).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Battery Current | 365 nA - enables >10-year coin-cell operation (CR2032) without compromising timekeeping accuracy |
| Accuracy | ±5 ppm typical after 2 reflows - ensures ≤2.6 sec/month drift under thermal cycling stress in production assembly |
| Operating Voltage | 2.0 V to 5.5 V - supports direct interface with 3.3 V and 5 V microcontrollers without level-shifting |
| Interface | I²C bus, 400 kHz - compatible with standard MCU I²C peripherals and avoids SPI resource contention |
| Temperature Range | –40 °C to +85 °C - qualified for industrial ambient environments including factory automation enclosures |
| Calendar Format | BCD-encoded registers - simplifies firmware parsing without binary-to-BCD conversion overhead |
| Alarm Function | Single programmable alarm with interrupt - triggers wake-up or logging event on match of time/date registers |
Pinout & Package
Package: 8-lead SOIC (4.90 mm × 3.90 mm), RoHS-compliant, surface-mount.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (FT/RST) | Open-drain reset output / frequency test | Asserts low during power-on reset; can be used as system watchdog reset signal or crystal frequency monitor |
| 2 (SDA) | I²C bidirectional data line | Requires external pull-up; supports multi-master arbitration and ACK/NACK handshaking per I²C spec |
| 3 (VBAT) | Battery supply input | Connects to coin cell (e.g., CR2032); powers RTC when VCC < 2.93 V; must tie to VSS if unused |
| 4 (SCL) | I²C clock input | Driven by master; defines timing for data sampling; supports standard/fast-mode I²C protocols |
| 5 (VSS) | Ground reference | Common return path for VCC, VBAT, and I/O; requires low-impedance PCB connection |
| 6 (XO) | Crystal oscillator output | Drives external 32.768 kHz tuning fork crystal; forms resonant tank with XI pin and load capacitance |
| 7 (XI) | Crystal oscillator input | Completes crystal feedback loop; internal circuitry provides gain and bias for stable oscillation |
| 8 (VCC) | Main supply voltage | Primary power source; initiates switchover to VBAT when falling below VRST threshold (2.93 V typ) |
Key Features
| Feature | Design Value |
|---|---|
| Automatic battery switchover | Seamless transition to VBAT at 2.93 V threshold with no clock glitch or register corruption |
| Programmable alarm interrupt | Single alarm maskable per register bit; generates interrupt even in battery-backup mode |
| Oscillator stop detection | Flags crystal failure via dedicated status bit; prevents invalid time accumulation during fault |
| 7-byte user SRAM | Persistent memory retained during VCC loss; accessible via same I²C address space as clock registers |
| Low-power design | 80 µA active current and 365 nA battery current enable energy-constrained edge-node deployment |
Applications
| Industrial PLC Time Stamping | Smart Meter Data Logging |
|---|---|
Use Scenario: Recording event timestamps (e.g., overcurrent trip, sensor fault) in programmable logic controllers during mains outage. IC Role / Device Role / Timing Role: Primary time-of-day source with battery backup; maintains monotonic calendar continuity across power cycles. Use Value: Ensures audit-trail compliance by preserving exact UTC-aligned timestamps without dependency on network time sync. | Use Scenario: Storing interval-based consumption data (kWh, gas m³) with time stamps in utility meters operating off-grid for months. IC Role / Device Role / Timing Role: Standalone RTC managing billing-period boundaries and firmware update scheduling independent of communication module uptime. Use Value: Eliminates need for supercapacitor hold-up circuitry while guaranteeing ≥10-year battery-backed operation at <1 µA average system current. |
| Medical Infusion Pump Scheduling | Building Automation HVAC Logs |
Use Scenario: Triggering drug delivery sequences and recording dose administration times in battery-powered infusion pumps. IC Role / Device Role / Timing Role: Safety-critical timekeeper enabling ISO 13485-compliant event logging with tamper-resistant timestamping. Use Value: Meets FDA 21 CFR Part 11 requirements for electronic records via deterministic, non-volatile time stamp generation. | Use Scenario: Logging temperature setpoint changes and occupancy sensor events across distributed HVAC controllers in commercial buildings. IC Role / Device Role / Timing Role: Distributed time coordinator synchronizing log entries across RS-485 network nodes without central NTP server. Use Value: Enables cross-node correlation of energy usage patterns using aligned local timestamps, reducing cloud-sync latency and bandwidth. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar real-time clock applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS1307+ (Maxim Integrated) | Lacks oscillator stop detection and digital/analog calibration; higher 500 nA battery current | No built-in century bit or leap-year correction; limited alarm flexibility | Choose for cost-sensitive legacy designs where ±20 ppm accuracy suffices and firmware handles calendar math |
| PCF8563 (NXP) | Lower 0.8 µA active current but no programmable alarm interrupt; only 1 byte of SRAM | Supports I²C timeout detection but lacks VCC switchover hysteresis control | Prefer for ultra-low-active-power systems where alarm triggering is handled externally via GPIO polling |
Compared with DS1307+ and PCF8563, the M41T82SM6E delivers superior long-term accuracy stability through dual-stage calibration, robust power-fail resilience via fixed-reference switchover, and integrated alarm interrupt that remains functional during battery-only operation - critical for unattended industrial deployments.
Availability
M41T82SM6E is available at Aetrix Electronics and suitable for industrial PLC time stamping, smart meter data logging, medical infusion pump scheduling, and building automation HVAC logs requiring stable component supply across extended product lifecycles.
Supply support for M41T82SM6E includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, analog ICs, power management devices, and sensors for industrial, automotive, and consumer markets.
The M41T82SM6E belongs to ST's serial RTC product line, engineered specifically for high-reliability, battery-backed timekeeping in harsh industrial environments where precision, low power, and long-term data integrity are mandatory.
FAQ
What crystal specifications are required for M41T82SM6E?
The M41T82SM6E requires a standard 32.768 kHz tuning-fork crystal with load capacitance of 12.5 pF, series resistance ≤50 kΩ, and drive level ≤1 µW. ST recommends crystals meeting EC-125 or IEC 60758 standards; layout must minimize trace length between XI/XO pins and ground plane.
Does M41T82SM6E support I²C clock stretching?
Yes - the M41T82SM6E fully supports I²C clock stretching during register read/write operations. When internal processing delays response, the device holds SCL low until ready, ensuring reliable communication even with slow microcontroller I²C peripherals or heavy bus loading.
How is the battery switchover threshold configured?
The switchover threshold (VSO = VRST) is fixed at 2.93 V (typical) and not user-programmable. This value is factory-trimmed and guaranteed across temperature; no external components or register writes affect the threshold, ensuring predictable behavior during brownout conditions.
Can the M41T82SM6E operate without a battery connected?
Yes - tie VBAT to VSS (ground) when no battery is used. The device functions normally on VCC alone, retaining time/calendar data only while powered. Battery disconnection does not damage the IC, but timekeeping ceases during VCC loss unless backup is provided.
M41T82SM6E Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Clock/Calendar
- Features:
- Alarm, Leap Year, SRAM, Watchdog Timer
- Memory Size:
- 7B
- Time Format:
- HH:MM:SS:hh (24 hr)
- Date Format:
- YY-MM-DD-dd
- Interface:
- I2C, 2-Wire Serial
- Voltage - Supply:
- 3V ~ 5.5V
- Voltage - Supply, Battery:
- 2V ~ 5.5V
- Current - Timekeeping (Max):
- 10µA @ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 8-SOIC
M41T82SM6E FAQ
1.How can I place an order for M41T82SM6E through Aetrix?
Please submit a Request for Quotation (RFQ) for M41T82SM6E on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for M41T82SM6E reliable?
The price and inventory of M41T82SM6E are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for M41T82SM6E is usually 5 days.
3.What payment methods are accepted for M41T82SM6E?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for M41T82SM6E transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for M41T82SM6E?
M41T82SM6E orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your M41T82SM6E order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for M41T82SM6E?
For technical support, including M41T82SM6E datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your M41T82SM6E requirements.
6.How does Aetrix verify that M41T82SM6E is sourced from the original manufacturer or authorized distributors?
All M41T82SM6E products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that M41T82SM6E meets industry standards.
7.What is the process for return or replacement of M41T82SM6E?
All M41T82SM6E units undergo pre-shipment inspection (PSI). If there is an issue with M41T82SM6E, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The M41T82SM6E part is unused and in its original packaging.
Return procedure for M41T82SM6E:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
M41T82SM6E Tags
-
MCP7940N-I/SN
Microchip Technology
-
MCP7940MT-I/MNY
Microchip Technology
-
PCF85063ATL/1,118
NXP USA Inc.
-
MCP7940NT-I/SN
Microchip Technology
-
MCP7940NT-I/MS
Microchip Technology
-
MCP7940N-I/MS
Microchip Technology
-
PCF85063AT/AY
NXP USA Inc.
-
PCF85063TP/1Z
NXP Semiconductors
-
PCF85063ATT/AJ
NXP USA Inc.
-
MCP7940NT-E/SN
Microchip Technology
-
MCP7940NT-I/MNY
Microchip Technology
-
MCP79400T-I/SN
Microchip Technology
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