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Microchip Technology MCP795W20T-I/ST
- Part No.:
- MCP795W20T-I/ST
- Manufacturer:
- Microchip Technology
- Category:
- Real Time Clocks
- Package:
- 14-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
MCP795W20T-I/ST.pdf
- Description:
- IC RTC CLK/CALENDAR SPI 14TSSOP
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
MCP795W20T-I/ST from Microchip Technology is a battery-backed SPI Real-Time Clock/Calendar (RTCC) IC with integrated watchdog timer, dual event detect modules, 2 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 or external clock input, and logs power-fail/power-up timestamps. Used in industrial metering, data loggers, and backup-critical embedded systems.
For engineers reviewing the MCP795W20T-I/ST datasheet, MCP795W20T-I/ST pinout, MCP795W20T-I/ST application, or MCP795W20T-I/ST equivalent, key selection factors include ±1 ppm digital trimming range, 1.0 µA VBAT timekeeping current, dual programmable alarms, open-drain IRQ/WDO outputs, and EUI-64™ preprogrammed address support.
Technical Context
The MCP795W20T-I/ST implements a fully autonomous RTCC using an internal 32.768 kHz oscillator circuit optimized for 6–9 pF crystals, with on-chip digital trimming (±259 ppm range, ±1 ppm resolution) for long-term accuracy. Its SPI interface operates up to 5 MHz at 2.5–3.6 V or 3 MHz at 1.8–2.5 V, with CS setup/hold times of 100 ns and data valid window of 100 ns.
Power management includes automatic switchover between VCC (1.8–3.6 V) and VBAT (1.3–3.6 V) at 1.5 V typical trip point, plus dedicated power-fail timestamp registers that log exact time of VCC loss and restoration. The device retains RTC state and SRAM contents during backup operation with ≤1.0 µA typical current at 3.0 V VBAT.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Time Resolution | Hundredth-of-second granularity with leap-year compensation through year 2399 |
| Oscillator Accuracy | ±1 ppm trimming resolution over ±259 ppm range; supports 6–9 pF crystals |
| Timekeeping Current | 1.0 µA typical from VBAT at 3.0 V; enables >10-year coin-cell battery life |
| SPI Interface Speed | Up to 5 MHz (VCC ≥2.5 V); full compatibility with PIC® MCU SPI peripherals |
| Memory Resources | 2 Kbit EEPROM (page write up to 8 bytes), 64-byte battery-backed SRAM, 128-bit protected EEPROM with EUI-64™ MAC address |
| Alarm & Event Logic | Dual independent alarms (hour–month match); high-speed pulse counter and low-speed switch debouncer with configurable interrupt outputs |
| Operating Temperature | -40°C to +85°C industrial grade; validated across full voltage range (1.8–3.6 V) |
Pinout & Package
14-pin SOIC (3.9 mm × 8.7 mm) and TSSOP packages; RoHS-compliant, Pb-free, halogen-free.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| X1 | Crystal Input / External Clock Input | Accepts 32.768 kHz crystal or external clock; also used for oscillator start/stop control via ST bit |
| X2 | Crystal Output | Drives crystal resonator; must be left floating when external clock mode is enabled |
| VBAT | Backup Supply Input | Provides power to RTC and SRAM during VCC loss; supports 1.3–3.6 V range with automatic switchover |
| WDO | Watchdog Timer Output | Open-drain output for WDT timeout pulses or alarm signals; requires external pull-up resistor |
| IRQ | Interrupt Request Output | Open-drain output for event detect interrupts or alarm signals; configurable to VCC or VBAT pull-up |
| CS | Chip Select Input | Active-low SPI enable; initiates instruction decoding on high-to-low transition after power-up |
| VSS | Ground Reference | Primary ground return for all digital and analog circuitry; must be connected before VCC/VBAT |
| SO | Serial Data Output | High-impedance tri-state output; data updated on SCK falling edge during read cycles |
| SI | Serial Data Input | Accepts instructions, addresses, and data; sampled on SCK rising edge |
| SCK | Serial Clock Input | Master-generated clock synchronizing all SPI transfers; rise/fall times ≤100 ns |
| EVHS | High-Speed Event Detect Input | Accepts fast digital pulses (e.g., encoder outputs); generates IRQ on programmable count threshold |
| EVLS | Low-Speed Event Detect Input | Accepts mechanical switch inputs; provides hardware debounce with selectable timing window |
| CLKOUT | Clock Output | Configurable square-wave output (32.768 kHz, 1 Hz, or user-defined frequency); can drive external logic directly |
| VCC | Main Power Supply | Primary operating supply (1.8–3.6 V); powers EEPROM writes, SPI communication, and active RTCC functions |
Key Features
| Feature | Design Value |
|---|---|
| Digital Trimming Calibration | ±259 ppm adjustment range with ±1 ppm resolution eliminates need for external trim capacitors |
| Power-Fail Timestamp Logging | Two independent timestamp registers capture exact time of VCC loss and restoration for system diagnostics |
| Dual Event Detection Modules | Hardware-accelerated pulse counting (EVHS) and switch debouncing (EVLS) reduce MCU firmware overhead |
| Protected EEPROM Area | 128-bit block with robust unlock sequence stores EUI-64™ MAC address or other immutable identifiers |
| Backup-Supply Optimized Operation | 1.0 µA VBAT current at 3.0 V enables >10-year operation on CR2032 coin cell without compromising accuracy |
Applications
| Smart Energy Metering | Industrial Data Logger |
|---|---|
Use Scenario: Utility-grade electricity meters requiring tamper-proof time-stamped consumption records and regulatory compliance with IEC 62053. IC Role / Device Role / Timing Role: Primary time source with power-fail timestamping, secure EUI-64™ identity storage, and alarm-triggered event logging. Use Value: Maintains traceable, battery-backed time continuity during mains outages and supports firmware update authentication via protected EEPROM. | Use Scenario: Remote environmental monitoring nodes deployed in unattended locations with infrequent maintenance cycles. IC Role / Device Role / Timing Role: Autonomous timekeeper and event coordinator-synchronizes sensor sampling, triggers data uploads on schedule, and logs fault conditions. Use Value: Enables decade-long operation on primary battery by minimizing active current (1.0 µA VBAT) while preserving accurate time and SRAM state across power interruptions. |
| Medical Device Clocking | POS Terminal Time Security |
Use Scenario: Portable diagnostic equipment needing FDA-compliant audit trails with precise time-of-event stamps for clinical data. IC Role / Device Role / Timing Role: Certified real-time clock with leap-year compensation, dual alarms for calibration reminders, and tamper-resistant timestamp registers. Use Value: Ensures regulatory compliance by guaranteeing time integrity across power cycles and providing verifiable, non-volatile time logs. | Use Scenario: Payment terminals requiring PCI-DSS-compliant transaction time stamping and secure device identification. IC Role / Device Role / Timing Role: Secure time source with EUI-64™ MAC address stored in protected EEPROM and power-fail logging for forensic transaction auditing. Use Value: Prevents time manipulation attacks by binding cryptographic keys to hardware-unique identifiers and maintaining auditable time continuity during brownouts. |
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 |
|---|---|---|---|
| MCP795W22T-I/ST | Same package and pinout; preprogrammed with EUI-64™ address (MCP795W20T-I/ST has blank protected EEPROM) | Required where IEEE-compliant 64-bit node addressing is mandatory for networked devices | Select MCP795W22T-I/ST if EUI-64™ is needed; otherwise MCP795W20T-I/ST offers identical RTCC functionality at lower cost |
| DS3231M+ | Higher accuracy (±2 ppm over -40°C to +85°C) with integrated TCXO; I²C interface only; no event detect or watchdog output | Preferred for ultra-high-precision timing where SPI interface and auxiliary peripherals are not required | Choose DS3231M+ only when sub-2 ppm accuracy is critical and system design can accommodate I²C-only communication and no WDO/EVHS/EVLS pins |
Compared with MCP795W22T-I/ST, the MCP795W20T-I/ST provides identical timekeeping, memory, and peripheral functionality but omits factory-programmed EUI-64™-reducing cost where unique addressing is handled externally. Versus DS3231M+, it trades absolute accuracy for SPI flexibility, integrated watchdog, and dual event detection-making it better suited for resource-constrained microcontroller systems requiring multiple timing-aware peripherals.
Availability
MCP795W20T-I/ST is available at Aetrix Electronics and suitable for smart energy metering, industrial data loggers, and medical device clocking requiring stable component supply, long-term lifecycle support, and guaranteed traceability.
Supply support for MCP795W20T-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, with global manufacturing and support infrastructure.
The MCP795Wxx family was designed for embedded systems requiring autonomous, battery-backed timekeeping with integrated system supervision features-including watchdog, event detection, and secure identity storage-targeting industrial, medical, and utility applications.
FAQ
What is the crystal load capacitance requirement for MCP795W20T-I/ST?
The MCP795W20T-I/ST is optimized for 32.768 kHz tuning fork crystals with a specified load capacitance of 6–9 pF. External load capacitors CX1 and CX2 must be selected to match the crystal's CL specification, accounting for pin capacitance (~3 pF) and PCB stray capacitance. Crystals rated for 12.5 pF are not recommended.
Does MCP795W20T-I/ST support both 12-hour and 24-hour time formats?
Yes, MCP795W20T-I/ST supports both 12-hour and 24-hour time formats. The format is selected via the 12/24 bit in the RTCHOUR register (address 0x03), and this setting applies consistently across timekeeping, alarm comparison, and timestamp registers.
How does the power-fail timestamp function work in MCP795W20T-I/ST?
The MCP795W20T-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). These timestamps are captured during switchover events and remain accessible via SPI regardless of backup supply state.
Can MCP795W20T-I/ST operate without an external crystal?
Yes, MCP795W20T-I/ST supports external clock input mode: connect a 32.768 kHz signal to the X1 pin and leave X2 floating, then set the EXTOSC bit in the CONTROL register (0x08). This bypasses the internal oscillator circuit and allows use with precision clock sources or shared system clocks.
What is the endurance rating of the EEPROM in MCP795W20T-I/ST?
The 2 Kbit EEPROM in MCP795W20T-I/ST is rated for 1 million erase/write cycles under standard conditions (VCC = 3.6 V, TA = 25°C), with page-write capability supporting up to 8 bytes per operation. Software write-protection prevents accidental modification of critical configuration data.
MCP795W20T-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, 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
MCP795W20T-I/ST FAQ
1.How can I place an order for MCP795W20T-I/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for MCP795W20T-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 MCP795W20T-I/ST reliable?
The price and inventory of MCP795W20T-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 MCP795W20T-I/ST is usually 5 days.
3.What payment methods are accepted for MCP795W20T-I/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MCP795W20T-I/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MCP795W20T-I/ST?
MCP795W20T-I/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MCP795W20T-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 MCP795W20T-I/ST?
For technical support, including MCP795W20T-I/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MCP795W20T-I/ST requirements.
6.How does Aetrix verify that MCP795W20T-I/ST is sourced from the original manufacturer or authorized distributors?
All MCP795W20T-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 MCP795W20T-I/ST meets industry standards.
7.What is the process for return or replacement of MCP795W20T-I/ST?
All MCP795W20T-I/ST units undergo pre-shipment inspection (PSI). If there is an issue with MCP795W20T-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 MCP795W20T-I/ST part is unused and in its original packaging.
Return procedure for MCP795W20T-I/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MCP795W20T-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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