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Microchip Technology MCP795W11T-I/ST
- Part No.:
- MCP795W11T-I/ST
- Manufacturer:
- Microchip Technology
- Category:
- Real Time Clocks
- Package:
- 14-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
MCP795W11T-I/ST.pdf
- Description:
- IC RTC CLK/CALENDAR SPI 14TSSOP
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
MCP795W11T-I/ST from Microchip Technology is a battery-backed SPI Real-Time Clock/Calendar (RTCC) IC with integrated watchdog timer, dual event detect modules, 1 Kbit EEPROM, and 64-byte SRAM. It maintains time to hundredth-of-second resolution across -40°C to +85°C, supports 32.768 kHz crystal (6–9 pF), delivers ±1 ppm digital trimming, and logs power-fail/power-up timestamps - used in industrial control panels requiring precise, nonvolatile timekeeping under brownout conditions.
For engineers reviewing the MCP795W11T-I/ST datasheet, MCP795W11T-I/ST pinout, MCP795W11T-I/ST application, or MCP795W11T-I/ST equivalent, key selection criteria include its 14-pin SOIC/TSSOP package, 1.8–3.6 V operating range, 1.2 µA typical timekeeping current from VCC, SPI interface up to 5 MHz, and EUI-48™ MAC address preprogrammed in protected EEPROM.
Technical Context
The MCP795W11T-I/ST implements a fully autonomous RTCC with BCD-encoded time registers (hundredths of seconds through year), leap-year compensation to 2399, and 12/24-hour mode selection. Its oscillator circuit supports both external 32.768 kHz crystals (with on-chip digital trimming ±259 ppm range) and external clock input via X1 pin.
It integrates three independent interrupt-capable peripherals: dual programmable alarms assignable to IRQ or WDO pins, high-speed event detect (pulse counting) and low-speed event detect (switch debouncing), plus a dedicated watchdog timer with configurable timeout and open-drain WDO output. Power management includes automatic switchover at 1.3–1.7 V VTRIP and backup operation down to 1.3 V VBAT.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Time Resolution | Hundredth-of-second precision with BCD-encoded registers for hours, minutes, seconds, date, month, year, day-of-week |
| Oscillator Accuracy | ±1 ppm trimming resolution over ±259 ppm range; optimized for 6–9 pF 32.768 kHz crystals |
| Supply Range | 1.8–3.6 V main supply (VCC); 1.3–3.6 V backup supply (VBAT) with automatic switchover at 1.5 V typical |
| Timekeeping Current | 1.2 µA typical at 3.0 V VCC; 1.0 µA typical at 3.0 V VBAT - enables >10-year coin-cell battery life |
| SPI Interface | Up to 5 MHz clock rate (≥2.5 V VCC); MSb-first protocol with CS-controlled enable and SO high-impedance when deselected |
| Memory Resources | 64-byte battery-backed SRAM; 1 Kbit software write-protected EEPROM; 128-bit protected EEPROM with preprogrammed EUI-48™ |
| Temperature Range | Industrial grade: -40°C to +85°C ambient operation with full parameter guarantee |
Pinout & Package
Package: 14-lead SOIC (MCP795W11T-I/ST) and TSSOP - RoHS-compliant, surface-mount, 1.27 mm pitch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| X1 | Crystal Input / External Clock Input | Accepts 32.768 kHz crystal (with X2) or external clock signal; also serves as oscillator enable control point via ST bit |
| X2 | Crystal Output | Completes crystal oscillator loop; must be connected to crystal; left floating if external clock mode selected |
| VBAT | Battery Backup Supply | Powers RTCC and SRAM during VCC loss; requires VCC applied before VBAT for reliable switchover |
| WDO | Watchdog Timer Output | Open-drain output for WDT timeout pulses or alarm signals; requires external 10 kΩ pull-up to VCC or VBAT |
| IRQ | Interrupt Request Output | Open-drain output for event detect interrupts or alarm signals; pull-up required; remains low until flag cleared |
| CS | Chip Select Input | Active-low SPI slave select; initiates instruction decode on high-to-low transition; enables bus sharing |
| VSS | Ground Reference | Primary return path for all digital and analog circuits; must be low-impedance connection to system ground |
| SO | Serial Data Output | Tri-state SPI MISO; outputs data on falling SCK edge; enters high-Z when CS is high |
| SI | Serial Data Input | SPI MOSI; latches instruction/address/data on rising SCK edge; sampled after CS goes low |
| SCK | Serial Clock Input | SPI clock input; synchronizes all data transfers; rise/fall times ≤100 ns required for 5 MHz operation |
| EVHS | High-Speed Event Detect Input | Detects fast pulses (e.g., encoder signals); configurable count threshold; tie to VCC/VSS if unused |
| EVLS | Low-Speed Event Detect Input | Debounces mechanical switches with programmable timing; tie to VCC/VSS if unused |
| CLKOUT | Clock Output | Configurable square-wave output (32.768 kHz, 1 kHz, 1 Hz, or 1/60 Hz); can serve as system clock source |
| VCC | Main Power Supply | Primary 1.8–3.6 V supply; powers all logic, EEPROM writes, and SPI interface; must ramp before VBAT |
Key Features
| Feature | Design Value |
|---|---|
| Power-Fail Timestamp Logging | Automatically records exact time of VCC loss and restoration in dedicated registers (PWRDNxxx/PWRUPxxx), enabling forensic power-event analysis |
| Dual Programmable Alarms | Two independent alarms with maskable fields (down to hundredth-of-second); assignable to IRQ or WDO pins for flexible interrupt routing |
| On-Chip Digital Trimming | ±1 ppm resolution adjustment over ±259 ppm range eliminates need for external trim caps or calibration hardware |
| EUI-48™ MAC Address | 128-bit protected EEPROM preprogrammed with globally unique IEEE EUI-48 identifier - usable for device authentication or network addressing |
| Event Detection Flexibility | Separate high-speed (pulse counting) and low-speed (debounce) modules eliminate need for external logic or firmware polling |
Applications
| Industrial Control Panel | Smart Energy Meter |
|---|---|
Use Scenario: Time-stamping of operator actions, alarm events, and process log entries in PLC-connected HMI panels operating across wide temperature ranges. IC Role / Device Role / Timing Role: Primary RTCC providing synchronized, battery-backed timekeeping and power-fail logging for audit trail compliance. Use Value: Ensures timestamp integrity during mains interruptions; EUI-48™ enables secure firmware update authentication without external ID storage. | Use Scenario: Recording energy consumption intervals, tariff switching events, and tamper detection timestamps in DIN-rail mounted meters. IC Role / Device Role / Timing Role: Standalone timekeeper with dual alarms triggering tariff changes and low-speed event detect monitoring meter cover switches. Use Value: 1.2 µA VCC timekeeping current extends supercapacitor hold-up time; ±1 ppm trimming meets IEC 62053-21 Class 0.5S accuracy requirements. |
| Medical Infusion Pump | Building Automation Controller |
Use Scenario: Logging drug delivery start/stop times, occlusion alerts, and maintenance cycles in battery-powered portable infusion systems. IC Role / Device Role / Timing Role: Fault-tolerant RTCC maintaining accurate time during battery swaps and main power transitions. Use Value: Power-fail timestamping captures exact moment of power loss for safety-critical event reconstruction; 64-byte SRAM stores last-dose parameters across power cycles. | Use Scenario: Coordinating HVAC scheduling, occupancy sensor triggers, and lighting control sequences in distributed BAS nodes. IC Role / Device Role / Timing Role: Central timing hub with CLKOUT driving secondary controllers and EVHS detecting zone occupancy pulses. Use Value: Dual event detect modules replace discrete debounce ICs; 1 Kbit EEPROM stores configuration profiles and firmware version history. |
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 |
|---|---|---|---|
| MCP795W12T-I/ST | Same package and pinout; includes EUI-64™ instead of EUI-48™ in protected EEPROM | Required where 64-bit node addressing (e.g., IPv6 autoconfiguration) is mandated over 48-bit MAC | Select MCP795W12T-I/ST only if EUI-64™ is explicitly needed; otherwise MCP795W11T-I/ST provides identical timing and feature set |
| DS3231SN#T&R | Higher accuracy (±2 ppm TCXO vs. ±1 ppm trimmed XO); no event detect or watchdog; different SPI command set and register map | Preferred for ultra-high-accuracy timekeeping where auxiliary functions (alarms, events, WDT) are handled externally | Choose DS3231SN#T&R only when sub-2 ppm stability is critical and system design accommodates missing integrated peripherals |
Compared with MCP795W12T-I/ST, the MCP795W11T-I/ST offers identical timing performance and peripheral integration but substitutes EUI-48™ for EUI-64™ - reducing memory overhead for legacy MAC-based networks. Against DS3231SN#T&R, it trades absolute oscillator accuracy for on-chip event handling and watchdog functionality, simplifying system-level design at moderate accuracy cost.
Availability
MCP795W11T-I/ST is available at Aetrix Electronics and suitable for industrial control panels, smart energy meters, medical infusion pumps, and building automation controllers requiring stable component supply with guaranteed long-term availability and traceable sourcing.
Supply support for MCP795W11T-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 microcontroller, mixed-signal, analog, and Flash-IP solutions, serving automotive, industrial, consumer, and communications markets with vertically integrated silicon and development tools.
The MCP795Wxx family is designed for embedded systems needing autonomous, low-power timekeeping with integrated system supervision - combining RTCC, EEPROM, SRAM, watchdog, and event detection in a single SPI-accessible IC.
FAQ
What is the primary function of the MCP795W11T-I/ST in a system?
The MCP795W11T-I/ST serves as a battery-backed SPI Real-Time Clock/Calendar (RTCC) that maintains accurate time and date across power cycles, logs power-fail/power-up events, and provides auxiliary functions including dual alarms, watchdog timer, and event detection. Its core role is autonomous timekeeping with integrated system supervision - eliminating reliance on host MCU resources for timing-critical tasks.
Does the MCP795W11T-I/ST require external load capacitors for crystal operation?
Yes, the MCP795W11T-I/ST requires external load capacitors (CX1, CX2) connected to X1 and X2 pins when using a 32.768 kHz crystal. It is optimized for crystals with 6–9 pF load capacitance; capacitor values must be selected to match the crystal's specified CL while accounting for pin and PCB stray capacitance per Equation 5-1 in the datasheet.
How does the power-fail timestamp feature work in the MCP795W11T-I/ST?
The MCP795W11T-I/ST automatically logs the exact time of VCC loss (power-down timestamp) and VCC restoration (power-up timestamp) into dedicated registers (0x18–0x1B and 0x1C–0x1F). This occurs during switchover between VCC and VBAT supplies and requires no host intervention - enabling post-failure diagnostics and audit-trail compliance in industrial and medical applications.
What memory resources are included in the MCP795W11T-I/ST?
The MCP795W11T-I/ST includes 64 bytes of battery-backed SRAM (addresses 0x20–0x5F), 1 Kbit (128-byte) software write-protected EEPROM, and 128 bits (16-byte) of protected EEPROM preprogrammed with an EUI-48™ MAC address. All memory remains accessible and retained during VCC loss via VBAT supply.
Can the MCP795W11T-I/ST operate without a crystal?
Yes, the MCP795W11T-I/ST supports external clock input mode: a 32.768 kHz clock signal can be applied directly to the X1 pin while leaving X2 floating. The EXTOSC bit in the CONTROL register must be set to enable this mode, bypassing the internal crystal oscillator circuit entirely.
MCP795W11T-I/ST Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 14-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Clock/Calendar
- Features:
- Alarm, EEPROM, Leap Year, Square Wave Output, SRAM, Unique ID, Watchdog Timer
- Memory Size:
- 64B
- Time Format:
- HH:MM:SS:hh (12/24 hr)
- Date Format:
- YY-MM-DD-dd
- Interface:
- SPI
- Voltage - Supply:
- 1.8V ~ 3.6V
- Voltage - Supply, Battery:
- 1.3V ~ 3.6V
- Current - Timekeeping (Max):
- 1µA @ 1.8V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 14-TSSOP
MCP795W11T-I/ST FAQ
1.How can I place an order for MCP795W11T-I/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for MCP795W11T-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 MCP795W11T-I/ST reliable?
The price and inventory of MCP795W11T-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 MCP795W11T-I/ST is usually 5 days.
3.What payment methods are accepted for MCP795W11T-I/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MCP795W11T-I/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MCP795W11T-I/ST?
MCP795W11T-I/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MCP795W11T-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 MCP795W11T-I/ST?
For technical support, including MCP795W11T-I/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MCP795W11T-I/ST requirements.
6.How does Aetrix verify that MCP795W11T-I/ST is sourced from the original manufacturer or authorized distributors?
All MCP795W11T-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 MCP795W11T-I/ST meets industry standards.
7.What is the process for return or replacement of MCP795W11T-I/ST?
All MCP795W11T-I/ST units undergo pre-shipment inspection (PSI). If there is an issue with MCP795W11T-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 MCP795W11T-I/ST part is unused and in its original packaging.
Return procedure for MCP795W11T-I/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MCP795W11T-I/ST Tags
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MCP7940N-I/SN
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