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Home > Products > Integrated Circuits (ICs) > Clock/Timing > Real Time Clocks

STMicroelectronics M41T00CAPPC1

Name: M41T00CAPPC1
Brand: STMicroelectronics
SKU: M41T00CAPPC1
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: M41T00CAPPC1

Manufacturer:: STMicroelectronics

Category:: Real Time Clocks

Package:: 24-DIP (0.600", 15.24mm)

Datasheet:: M41T00CAPPC1.pdf

Description:: IC RTC CLK/CALENDAR I2C 24-DIP

Quantity:: RFQ Add To RFQ list

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Inventory:4,545

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Product details

Overview

M41T00CAP from STMicroelectronics is a self-contained serial real-time clock (RTC) IC with integrated lithium coin cell and 32.768 kHz crystal in a 24-pin CAPHAT™ DIP package. It provides full BCD-coded calendar/timekeeping (seconds to century), automatic VCC-to-battery switchover at 2.6 V (typ), 400 kHz I²C interface, and oscillator fail detection - deployed in industrial control panels requiring tamper-resistant, maintenance-free timekeeping across power interruptions.

For engineers reviewing the M41T00CAP datasheet, M41T00CAP pinout, M41T00CAP application, or M41T00CAP equivalent, this page delivers verified technical context on switchover threshold behavior, register-level BCD calendar operation, battery-backed data retention, and I²C timing compliance per ST's DocID014557 Rev 6.

Technical Context

The M41T00CAP operates as an I²C slave device with fixed 7-bit address 0xD0h, supporting sequential READ/WRITE of eight registers (00h–07h) containing century-aware calendar data and calibration value. Its internal BiPORT™ TIMEKEEPER architecture isolates user-accessible registers from active timekeeping counters to prevent read corruption during updates.

Power management uses dual voltage thresholds: VPFD (2.6 V typ) triggers power-fail deselect and address counter reset, while VSO enables seamless switchover to VBAT. The STOP bit (D7 of register 00h) halts the 32.768 kHz oscillator, reducing current to <1 µA in storage mode - validated for ≥10-year battery life under continuous backup.

Key Specifications

Parameter	Value and Actual Design Meaning
I²C Speed	400 kHz maximum - supports standard-mode I²C timing without external pull-up adjustment.
Operating Voltage	2.7–5.5 V - compatible with 3.3 V and 5 V logic systems without level shifting.
Switchover Threshold	2.6 V (typ) - ensures reliable battery takeover before system brownout affects host MCU operation.
Backup Current	300 µA (typ) - enables >10-year runtime on integrated Li coin cell under continuous RTC operation.
Temperature Range	0 to 70 °C - qualified for commercial/industrial ambient environments without derating.
Oscillator Accuracy	±23 ppm at 25 °C - translates to ±1 minute/month drift, sufficient for non-precision timestamping.
Calendar Format	BCD-encoded registers (00h–06h) with automatic leap-year correction through year 2100.

Pinout & Package

Package: 24-pin PCDIP24 CAPHAT™ - hermetically sealed plastic DIP with integrated lithium battery and 32.768 kHz crystal; footprint-compatible with standard 0.6-inch DIP sockets.

Pin/Terminal	Circuit Role	Design Meaning
SCL	I²C clock input	Master-generated clock synchronizing all data transfers; requires external pull-up resistor.
SDA	I²C bidirectional data line	Open-drain interface shared with other I²C devices; must be pulled up externally.
VCC	Main supply input	Primary power source; monitored for switchover; range 2.7–5.5 V.
VSS	Ground reference	Common return path for VCC and VBAT circuits; must be low-impedance.
FT/OUT	Frequency test / open-drain output	Provides 32.768 kHz square wave for calibration; can drive LED or logic input with external pull-up.
DU	Do-not-use terminal	Factory-reserved pin; must float - no connection to VCC, VSS, or PCB traces.

Key Features

Feature	Design Value
Integrated battery + crystal	Eliminates external component sourcing, layout, and qualification - reduces BOM count by 2 items.
Automatic switchover circuitry	Hardware-based VCC monitoring with fixed 2.6 V threshold ensures deterministic failover without firmware intervention.
Century-aware BCD calendar	Registers 00h–06h encode full date/time including century bit (CB) and enable (CEB); leap-year logic valid to 2100.
Oscillator stop detection	OF bit (D6 of register 01h) flags crystal failure or disconnection - enables field diagnostics without external sensors.
Software calibration register	Register 07h holds binary trim value adjusting oscillator frequency in ±10 ppm steps - corrects aging or temperature drift.

Applications

Industrial HMI Panels

Energy Metering Gateways

Use Scenario: Standalone time-stamping of energy consumption logs during grid outages.

IC Role / Device Role / Timing Role: Primary RTC maintaining accurate UTC timestamps independent of host MCU power state.

Use Value: Integrated battery sustains timekeeping >10 years; switchover at 2.6 V prevents timestamp loss during brownouts.

Use Scenario: Synchronizing interval data uploads to cloud platforms when mains power is unstable.

IC Role / Device Role / Timing Role: Calendar engine providing BCD-formatted date/time for firmware logging and report generation.

Use Value: Automatic leap-year correction and century bit support ensure long-term date validity through 2100.

Medical Diagnostic Devices

Building Automation Controllers

Use Scenario: Timestamping patient vital sign records where audit trail integrity is regulated.

IC Role / Device Role / Timing Role: Tamper-resistant time source with oscillator fail detection for regulatory compliance reporting.

Use Value: OF bit alerts firmware to crystal failure; STOP bit allows safe shelf storage without battery drain.

Use Scenario: Coordinating HVAC scheduling and occupancy sensor events across distributed nodes.

IC Role / Device Role / Timing Role: Low-power RTC enabling deep-sleep wake-up synchronization without external crystal.

Use Value: 300 µA operating current extends battery life in wireless controllers; CAPHAT™ package simplifies enclosure sealing.

Equivalent & Alternatives

The following parts are listed as comparable options for similar RTC applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
DS1307+ (Maxim Integrated)	No integrated battery or crystal; requires external 32.768 kHz crystal and backup capacitor/cell.	Lacks self-contained power solution - increases BOM, layout complexity, and qualification effort.	Select when board space permits discrete components and long-term supply of legacy Maxim parts is assured.
PCF8563 (NXP)	Lower backup current (0.5 µA), but no integrated battery/crystal; supports trickle-charge only.	Requires external charging circuitry and crystal - unsuitable for sealed, maintenance-free designs.	Choose for ultra-low-power sleep modes where external battery management is already implemented.

Compared with DS1307+ and PCF8563, the M41T00CAP uniquely integrates battery and crystal in one RoHS-compliant CAPHAT™ package, eliminating external timing components and enabling true drop-in timekeeping with guaranteed 10-year backup life - critical for sealed industrial enclosures.

Availability

M41T00CAP is available at Aetrix Electronics and suitable for industrial HMI panels, energy metering gateways, medical diagnostic devices, and building automation controllers requiring stable component supply with guaranteed 10-year battery-backed operation.

Supply support for M41T00CAP 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, and timing solutions for industrial, automotive, and consumer markets.

The M41T00CAP belongs to ST's TIMEKEEPER® RTC product line, engineered specifically for maintenance-free, battery-backed timekeeping in sealed or inaccessible equipment - emphasizing integration, long-term reliability, and simplified system design.

FAQ

What is the function of the DU pin on the M41T00CAP?

The DU (Do Not Use) pin is reserved for factory testing and must remain unconnected and floating - it is not tied to VCC, VSS, or any PCB trace. Connecting DU may cause undefined behavior or damage. This requirement is explicitly stated in ST's datasheet (DocID014557 Rev 6, Table 1) and applies to all units in production.

How does the M41T00CAP handle leap years?

The M41T00CAP automatically adjusts for leap years through year 2100 using internal logic that evaluates the BCD-encoded year (register 06h) and month (register 05h). This is confirmed in Section 3.1 of the datasheet, which states "corrections for the number of days in a month, including leap year, are made automatically." No firmware intervention is required.

Can the FT/OUT pin drive an LED directly?

No - FT/OUT is an open-drain output requiring an external pull-up resistor to VCC. To drive an LED, connect the anode to VCC via a current-limiting resistor (e.g., 1 kΩ) and the cathode to FT/OUT. The pin sources no current; it only sinks up to 3 mA (per datasheet Section 5, DC characteristics), making direct LED drive unsafe without proper biasing.

Is the M41T00CAP pin-compatible with the M41T00M6?

No - the M41T00CAP uses a 24-pin CAPHAT™ DIP package, while the M41T00M6 is a 8-pin SOIC package without integrated battery or crystal. They share functional register maps and I²C protocol but differ physically and electrically in power architecture, pin count, and backup capability - confirmed by ST's ordering information (Figure 16, DocID014557 Rev 6).

M41T00CAPPC1 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: Timekeeper®, CAPHAT™

Package/Case:: 24-DIP (0.600", 15.24mm)

Packaging:: Tube

Product Status:: Obsolete

Programmable:: Not Verified

Type:: Clock/Calendar

Features:: Leap Year

Memory Size:: -

Time Format:: HH:MM:SS (24 hr)

Date Format:: YY-MM-DD-dd

Interface:: I2C, 2-Wire Serial

Voltage - Supply:: 2.7V ~ 5.5V

Voltage - Supply, Battery:: Integrated

Current - Timekeeping (Max):: 70µA @ 2.7V ~ 5.5V

Operating Temperature:: 0°C ~ 70°C

Mounting Type:: Through Hole

Grade:: -

Qualification:: -

Supplier Device Package:: 24-PCDIP, CAPHAT®

M41T00CAPPC1 FAQ

1.How can I place an order for M41T00CAPPC1 through Aetrix?

Please submit a Request for Quotation (RFQ) for M41T00CAPPC1 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 M41T00CAPPC1 reliable?

The price and inventory of M41T00CAPPC1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for M41T00CAPPC1 is usually 5 days.

3.What payment methods are accepted for M41T00CAPPC1?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for M41T00CAPPC1 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for M41T00CAPPC1?

M41T00CAPPC1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your M41T00CAPPC1 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 M41T00CAPPC1?

For technical support, including M41T00CAPPC1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your M41T00CAPPC1 requirements.

6.How does Aetrix verify that M41T00CAPPC1 is sourced from the original manufacturer or authorized distributors?

All M41T00CAPPC1 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 M41T00CAPPC1 meets industry standards.

7.What is the process for return or replacement of M41T00CAPPC1?

All M41T00CAPPC1 units undergo pre-shipment inspection (PSI). If there is an issue with M41T00CAPPC1, 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 M41T00CAPPC1 part is unused and in its original packaging.

Return procedure for M41T00CAPPC1:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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