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Microchip Technology MCP79411-I/ST
- Part No.:
- MCP79411-I/ST
- Manufacturer:
- Microchip Technology
- Category:
- Real Time Clocks
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
MCP79411-I/ST.pdf
- Description:
- IC RTC CLK/CALENDAR I2C 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,843
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Product details
Overview
MCP79411-I/ST from Microchip Technology is a battery-backed I²C Real-Time Clock/Calendar (RTCC) with integrated 64-byte SRAM, 1 Kbit EEPROM, and EUI-48™ MAC address. It maintains time across power loss using automatic VCC-to-VBAT switchover, supports ±1 ppm digital trimming over ±129 ppm range, and delivers 925 nA backup current at 3.0V for industrial metering and embedded control systems.
For engineers reviewing the MCP79411-I/ST datasheet, MCP79411-I/ST pinout, MCP79411-I/ST application, or MCP79411-I/ST equivalent, this page provides verified timing accuracy, I²C interface behavior at 400 kHz, power-fail timestamp logging, dual alarm configuration, and EUI-48 storage - all confirmed for the exact SOIC-8 package variant.
Technical Context
The MCP79411-I/ST implements a fully autonomous RTCC subsystem with BCD-encoded timekeeping registers (seconds to year), leap-year compensation through 2399, and dual programmable alarms configurable down to second granularity. Its oscillator circuit supports either 32.768 kHz crystal (6–9 pF load) or external clock input via X1, with OSCRUN status flag and TOSF = 1 ms timeout detection.
I²C communication uses two distinct slave addresses: 0xD8/0xD9 for RTCC/SRAM access and 0xA8/0xA9 for EEPROM operations. The MFP pin functions as open-drain alarm/square-wave output (selectable frequencies: 1 Hz, 4.096 kHz, 8.192 kHz, 32.768 kHz) or general-purpose output, requiring external pull-up.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Timekeeping Accuracy | ±1 ppm resolution with ±129 ppm digital trim range - enables field calibration to compensate crystal tolerance and temperature drift |
| Backup Current | 925 nA typical at 3.0V VBAT - extends coin-cell life beyond 10 years in always-on timekeeping applications |
| I²C Speed | Up to 400 kHz (≥2.5V VCC) - supports high-throughput register reads/writes without bus contention in multi-device systems |
| Oscillator Frequency | 32.768 kHz nominal - matches standard tuning fork crystals for low-power, stable timebase generation |
| Power Switchover Threshold | VTRIP = 1.3–1.7V - ensures seamless transition to backup supply before system brownout affects RTC operation |
| Protected Memory | EUI-48™ preprogrammed in 64-bit protected EEPROM - provides globally unique hardware identifier for networked device authentication |
| Alarm Capability | Dual independent alarms with maskable fields (second to month) - enables precise event scheduling without host MCU intervention |
Pinout & Package
Package: 8-pin SOIC (Small Outline Integrated Circuit), 150 mil width, surface-mount, RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| X1 | Crystal Input / External Clock Input | Accepts 32.768 kHz crystal or external clock signal; also serves as oscillator enable control point via ST bit |
| X2 | Crystal Output | Drives crystal resonator; must be left floating when external clock mode is active |
| VBAT | Battery Backup Supply Input | Provides power to RTCC and SRAM during main supply loss; operates from 1.3V to 5.5V |
| VSS | Ground Reference | Common return path for all internal circuits; must be low-impedance connection to system ground |
| SDA | I²C Bidirectional Data Line | Open-drain interface requiring external pull-up; supports 400 kHz operation with ≤300 ns fall time at ≥2.5V |
| SCL | I²C Clock Input | Master-generated clock synchronizing all data transfers; rise/fall times specified per VCC level |
| MFP | Multifunction Pin (Alarm/Square Wave/GPO) | Configurable open-drain output; requires pull-up resistor; asserts on alarm match or outputs selectable square wave |
| VCC | Main Power Supply | Primary operating voltage: 1.8V–5.5V; powers EEPROM writes, I²C logic, and oscillator circuitry |
Key Features
| Feature | Design Value |
|---|---|
| Power-Fail Timestamp Logging | Records exact time of VCC loss and restoration in dedicated PWRDN/PWRUP registers - enables forensic power-event analysis |
| Dual Programmable Alarms | Independent alarm 0 and alarm 1 with maskable fields (e.g., "alarm every Monday at 08:00") - reduces host polling overhead |
| On-Chip Digital Trimming | ±1 ppm step resolution over ±129 ppm range - eliminates need for external variable capacitors or manual calibration |
| Protected EEPROM Area | 64-bit write-protected region with robust unlock sequence - secures EUI-48™ MAC address against accidental overwrite |
| Low-Power Timekeeping | 1.2 µA typical ICC at 3.3V VCC and 925 nA at 3.0V VBAT - meets stringent energy budgets in battery-powered IoT nodes |
Applications
| Smart Energy Metering | Industrial PLC HMI |
|---|---|
Use Scenario: Utility-grade electricity meters requiring tamper-resistant time stamping for billing intervals and outage logging. IC Role / Device Role / Timing Role: Primary timekeeping engine with power-fail timestamp capture and EUI-48™ identity for secure firmware updates. Use Value: Maintains sub-second accuracy across 10+ year deployments while enabling regulatory-compliant event logging without host processor involvement. | Use Scenario: Human-machine interface panels in factory automation systems needing persistent time/date display and scheduled maintenance alerts. IC Role / Device Role / Timing Role: Standalone RTCC providing real-time calendar data and dual alarms for operator notifications and log rotation triggers. Use Value: Eliminates reliance on PLC CPU clock; guarantees time continuity during controller reboots or power interruptions. |
| Medical Infusion Pump | Networked Building Controller |
Use Scenario: Battery-operated infusion pumps requiring accurate therapy session timing and audit-trail timestamps for compliance. IC Role / Device Role / Timing Role: Fail-safe time source with battery backup and tamper-evident power-loss logging. Use Value: Delivers 925 nA VBAT current enabling >5-year coin-cell life while meeting IEC 62304 traceability requirements. | Use Scenario: HVAC controllers managing occupancy schedules, energy reporting, and remote diagnostics over BACnet/IP. IC Role / Device Role / Timing Role: Time anchor for local event scheduling and synchronized NTP client fallback during network outages. Use Value: Provides EUI-48™ MAC address for zero-touch device onboarding and deterministic time-stamped sensor data aggregation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar real-time clock/calendar applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MCP79410-I/ST | No preprogrammed EUI-48™; unprotected 64-bit EEPROM area | Lacks factory-assigned MAC address; requires external ID management | Select when unique hardware identity is not required and cost sensitivity outweighs traceability needs |
| DS3231M+ | Integrated TCXO (±2 ppm over -40°C to +85°C); higher accuracy but no EEPROM or EUI storage | Superior temperature stability but lacks nonvolatile memory and MAC address features | Select when absolute time accuracy dominates over memory integration and device identification |
Compared with MCP79410-I/ST, the MCP79411-I/ST adds factory-programmed EUI-48™ for plug-and-play networking, while DS3231M+ trades memory integration for superior oscillator stability - making MCP79411-I/ST optimal for cost-sensitive, identity-aware embedded systems requiring long-term battery-backed timekeeping.
Availability
MCP79411-I/ST is available at Aetrix Electronics and suitable for smart metering, industrial HMI, medical infusion devices, and building automation systems requiring stable component supply with guaranteed long-term availability.
Supply support for MCP79411-I/ST 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
Microchip Technology Inc. is a leading provider of microcontrollers, analog components, and timing solutions, headquartered in Chandler, Arizona.
The MCP7941X product line was designed specifically for embedded systems requiring autonomous, battery-backed timekeeping with integrated memory and hardware identity - targeting metering, industrial control, and medical devices.
FAQ
What is the primary function of the MCP79411-I/ST?
The MCP79411-I/ST is a battery-backed I²C Real-Time Clock/Calendar (RTCC) that maintains accurate time and date across power cycles. It integrates 64-byte SRAM, 1 Kbit EEPROM, and a factory-programmed EUI-48™ MAC address. Its core function is autonomous timekeeping with power-fail timestamp logging, dual alarms, and digital trimming - all implemented without host MCU intervention. The MCP79411-I/ST performs this role reliably in the MCP79411-I/ST's SOIC-8 package across industrial temperature ranges.
Does the MCP79411-I/ST support external crystal oscillators?
Yes, the MCP79411-I/ST supports external 32.768 kHz tuning fork crystals connected between X1 and X2 pins. It is optimized for crystals with 6–9 pF load capacitance and includes on-chip digital trimming to compensate for frequency variance. The ST bit in the RTCSEC register must be set to enable the crystal oscillator. The MCP79411-I/ST also supports external clock input on X1 when EXTOSC is enabled, with X2 left floating - both modes are validated for the MCP79411-I/ST.
How does the MCP79411-I/ST handle power failure events?
The MCP79411-I/ST automatically switches to VBAT backup supply when VCC drops below the 1.3–1.7V switchover threshold (VTRIP). During switchover, it logs exact timestamps in dedicated PWRDN and PWRUP registers. Both RTCC counters and 64-byte SRAM retain data without interruption. The MCP79411-I/ST maintains timekeeping at 925 nA typical current from VBAT at 3.0V - ensuring continuous operation through extended outages. This behavior is intrinsic to the MCP79411-I/ST design.
What memory resources are included in the MCP79411-I/ST?
The MCP79411-I/ST includes three memory types: 64-byte battery-backed SRAM (addresses 0x20–0x5F), 1 Kbit EEPROM (128 bytes, addresses 0x00–0x7F) with software write-protection and 8-byte page writes, and 64-bit protected EEPROM (addresses 0xF0–0xF7) preprogrammed with EUI-48™. All are accessible via I²C using separate slave addresses (0xD8/D9 for SRAM/RTCC, 0xA8/A9 for EEPROM). These memory resources are physically integrated and functionally verified in the MCP79411-I/ST.
Can the MCP79411-I/ST generate square wave outputs?
Yes, the MCP79411-I/ST can generate square wave outputs on the MFP pin. When SQWEN is set and OUT=0 in the CONTROL register, MFP outputs selectable frequencies: 1 Hz, 4.096 kHz, 8.192 kHz, or 32.768 kHz. This functionality coexists with alarm assertion and general-purpose output modes. The MFP is open-drain and requires an external pull-up resistor. This square wave capability is fully supported and characterized for the MCP79411-I/ST in its SOIC-8 package.
MCP79411-I/ST Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Clock/Calendar
- Features:
- Alarm, Leap Year, Square Wave Output, SRAM, Unique ID
- Memory Size:
- 64B, 1Kb
- Time Format:
- HH:MM:SS (12/24 hr)
- Date Format:
- YY-MM-DD-dd
- Interface:
- I2C, 2-Wire Serial
- Voltage - Supply:
- 1.8V ~ 5.5V
- Voltage - Supply, Battery:
- 1.3V ~ 5.5V
- Current - Timekeeping (Max):
- 1.2µA @ 3.3V
- Operating Temperature:
- -40°C ~ 85°C
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 8-TSSOP
MCP79411-I/ST FAQ
1.How can I place an order for MCP79411-I/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for MCP79411-I/ST 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 MCP79411-I/ST reliable?
The price and inventory of MCP79411-I/ST are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MCP79411-I/ST is usually 5 days.
3.What payment methods are accepted for MCP79411-I/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MCP79411-I/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MCP79411-I/ST?
MCP79411-I/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MCP79411-I/ST 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 MCP79411-I/ST?
For technical support, including MCP79411-I/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MCP79411-I/ST requirements.
6.How does Aetrix verify that MCP79411-I/ST is sourced from the original manufacturer or authorized distributors?
All MCP79411-I/ST 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 MCP79411-I/ST meets industry standards.
7.What is the process for return or replacement of MCP79411-I/ST?
All MCP79411-I/ST units undergo pre-shipment inspection (PSI). If there is an issue with MCP79411-I/ST, 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 MCP79411-I/ST part is unused and in its original packaging.
Return procedure for MCP79411-I/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MCP79411-I/ST 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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