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

Microchip Technology MCP795B11T-I/ST

Name: MCP795B11T-I/ST
Brand: Microchip Technology
SKU: MCP795B11T-I/ST
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MCP795B11T-I/ST

Manufacturer:: Microchip Technology

Category:: Real Time Clocks

Package:: 14-TSSOP (0.173", 4.40mm Width)

Datasheet:: MCP795B11T-I/ST.pdf

Description:: IC RTC CLK/CALENDAR SPI 14TSSOP

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Product details

Overview

MCP795B11T-I/ST from Microchip Technology is a SPI real-time clock/calendar (RTCC) IC with integrated 64-byte battery-backed SRAM, 1 Kbit EEPROM, EUI-48™ unique ID, and 32 kHz boot-up clock at power-up. It supports digital trimming (±255 ppm in 1 ppm steps), dual programmable alarms, power-fail time-stamping, and operates from 1.8V to 5.5V VCC and 1.3V to 5.5V VBAT. Used in industrial metering and backup-critical embedded systems for accurate timekeeping during main power loss.

For engineers reviewing the MCP795B11T-I/ST datasheet, MCP795B11T-I/ST pinout, MCP795B11T-I/ST application, or MCP795B11T-I/ST equivalent, key selection considerations include its 32 kHz boot-up capability, VBAT switchover behavior, CLKOUT/BOOT dual-function pin, 700 nA VBAT timekeeping current, and EUI-48™ preprogrammed ID support.

Technical Context

The MCP795B11T-I/ST integrates a 32.768 kHz crystal oscillator with automatic 32 kHz boot-up clock generation on CLKOUT/BOOT at power-up - a distinguishing feature of the MCP795BXX family absent in MCP795WXX variants. Its RTCC registers (0x00–0x1F) maintain BCD-encoded time/date with leap-year correction, hundredth-second resolution, and 12/24-hour format support.

It implements dual event detection inputs: EVHS supports pulse counting (1st/4th/16th/32nd edge), while EVLS provides programmable debounce (31 ms or 500 ms); both operate from VCC or VBAT. The watchdog timer features dedicated WDO output, dual retrigger (SPI or EVHS), and user-selectable pulse duration via register 0x0A:4.

Key Specifications

Parameter	Value and Actual Design Meaning
VCC Range	1.8V to 5.5V - enables direct interface with 1.8V, 3.3V, and 5V microcontrollers without level shifting.
VBAT Timekeeping Current	<700 nA @ 1.8V - ensures multi-year battery backup life using standard coin cells (e.g., CR2032).
SPI Clock Speed	Up to 10 MHz @ VCC ≥ 4.5V - supports fast register access and millisecond-resolution alarm programming.
Digital Trimming Range	±255 ppm in 1 ppm steps - allows precise calibration against reference clocks without external components.
EEPROM Endurance	1,000,000 erase/write cycles - suitable for frequent logging or configuration updates in field-deployed devices.
Power-Fail Time-Stamp	Logs timestamp on VCC fail and VCC restore - captures exact duration of brownout events for diagnostics and compliance reporting.
Unique ID	128-bit EUI-48™ preprogrammed - provides globally unique MAC address for networked devices without host-side provisioning.

Pinout & Package

Package: 14-lead SOIC (Small Outline Integrated Circuit), 150 mil width, RoHS-compliant, surface-mount.

Pin/Terminal	Circuit Role	Design Meaning
1 (X1)	Clock Input	Connects to 32.768 kHz crystal input or external CMOS clock source; internal oscillator start-up enabled by ST/CT bit.
2 (X2)	Clock Output	Crystal oscillator output node; must be left unconnected if X1 driven by external clock.
3 (VBAT)	Backup Supply	Provides continuous power to RTCC and SRAM during VCC loss; switchover threshold 1.3–1.7V (typ. 1.5V).
4 (WDO)	Watchdog Output	Open-drain N-channel output requiring external pull-up; pulses low on watchdog timeout (duration programmable).
5 (IRQ)	Interrupt Output	Shared open-drain output for alarms and event detects; requires external pull-up to VCC or VBAT.
6 (CS)	Chip Select	Active-low SPI slave select; initiates internal write cycle on rising edge after valid write sequence.
7 (VSS)	Ground	Primary ground reference for all digital and analog circuitry; must be low-impedance connection.
8 (SCK)	Serial Clock	SPI clock input; data latched on rising edge (SI), output updated after falling edge (SO).
9 (SI)	Serial Input	Master-to-slave SPI data input; accepts instructions, addresses, and data (MSb first).
10 (SO)	Serial Output	Slave-to-master SPI data output; tri-states when CS is high to enable bus sharing.
11 (EVLS)	Low-Speed Event Detect	Debounced input for mechanical switches; supports 31 ms or 500 ms filter delay, active from VCC or VBAT.
12 (EVHS)	High-Speed Event Detect	Edge-triggered (rising/falling) input with programmable pulse count (1st/4th/16th/32nd), operates from VCC or VBAT.
13 (CLKOUT/BOOT)	Multi-Function Output	Push-pull output generating 1 Hz / 4.096 kHz / 8.192 kHz / 32.768 kHz; asserts 32 kHz at power-up for MCP795BXX only.
14 (VCC)	Main Supply	Primary power input; device fully functional (SPI, EEPROM, alarms) when 1.8V ≤ VCC ≤ 5.5V.

Key Features

Feature	Design Value
32 kHz Boot-Up Clock	Automatically drives CLKOUT/BOOT with 32.768 kHz at power-on reset - eliminates need for external clock initialization in host firmware.
Dual Programmable Alarms	Alarm 0 (second resolution) and Alarm 1 (hundredth-second resolution) with independent IRQ routing and maskable interrupt flags.
Battery Switchover with Time-Stamp	Hardware-monitored VCC-to-VBAT transition logs exact timestamps of power failure and restoration in dedicated registers (0x18–0x1F).
EUI-48™ Unique ID	Factory-programmed 48-bit MAC address in protected EEPROM space - enables plug-and-play network identity without host-side MAC management.
On-Chip Digital Trimming	8-bit calibration register (±255 ppm, 1 ppm step) adjusts RTC increment rate per minute - replaces manual capacitor tuning for production calibration.
Event Detection Flexibility	Two independent inputs: EVHS for high-frequency pulse counting, EVLS for debounced switch inputs - reduces need for external signal conditioning.

Applications

Smart Energy Metering	Industrial PLC Data Logger
Use Scenario: Records energy consumption with time-stamped intervals during grid outages and recovery. IC Role / Device Role / Timing Role: Primary RTCC providing accurate time-of-use billing timestamps, backed by VBAT during AC loss. Use Value: Power-fail time-stamp registers (0x18–0x1F) capture exact outage duration, enabling regulatory compliance reporting without host CPU involvement.	Use Scenario: Logs sensor readings and system events in factory automation controllers with extended battery backup. IC Role / Device Role / Timing Role: Standalone timekeeping and nonvolatile storage element retaining timestamps and configuration across power cycles. Use Value: 64-byte SRAM + 1 Kbit EEPROM + 700 nA VBAT current enables >5-year backup using CR2032, reducing maintenance frequency.
Medical Infusion Pump	Networked Building Controller
Use Scenario: Tracks therapy session timing, dose delivery logs, and safety-critical event timestamps under strict IEC 62304 requirements. IC Role / Device Role / Timing Role: Certified time source with traceable calibration (digital trim), battery-switchover, and tamper-resistant time-stamp logging. Use Value: EUI-48™ ID enables secure device onboarding into hospital networks; 32 kHz boot-up clock ensures immediate timing availability post-power-cycle.	Use Scenario: Synchronizes HVAC scheduling, occupancy sensing, and energy reporting across distributed BACnet/IP nodes. IC Role / Device Role / Timing Role: Network endpoint timebase with unique MAC (EUI-48™) and alarm-driven event notification (e.g., door open/close). Use Value: Dual event detect inputs (EVHS/EVLS) directly interface with contact sensors and motion detectors, eliminating external GPIO expanders.

Smart Energy Metering

Industrial PLC Data Logger

Use Scenario: Records energy consumption with time-stamped intervals during grid outages and recovery.

IC Role / Device Role / Timing Role: Primary RTCC providing accurate time-of-use billing timestamps, backed by VBAT during AC loss.

Use Value: Power-fail time-stamp registers (0x18–0x1F) capture exact outage duration, enabling regulatory compliance reporting without host CPU involvement.

Use Scenario: Logs sensor readings and system events in factory automation controllers with extended battery backup.

IC Role / Device Role / Timing Role: Standalone timekeeping and nonvolatile storage element retaining timestamps and configuration across power cycles.

Use Value: 64-byte SRAM + 1 Kbit EEPROM + 700 nA VBAT current enables >5-year backup using CR2032, reducing maintenance frequency.

Medical Infusion Pump

Networked Building Controller

Use Scenario: Tracks therapy session timing, dose delivery logs, and safety-critical event timestamps under strict IEC 62304 requirements.

IC Role / Device Role / Timing Role: Certified time source with traceable calibration (digital trim), battery-switchover, and tamper-resistant time-stamp logging.

Use Value: EUI-48™ ID enables secure device onboarding into hospital networks; 32 kHz boot-up clock ensures immediate timing availability post-power-cycle.

Use Scenario: Synchronizes HVAC scheduling, occupancy sensing, and energy reporting across distributed BACnet/IP nodes.

IC Role / Device Role / Timing Role: Network endpoint timebase with unique MAC (EUI-48™) and alarm-driven event notification (e.g., door open/close).

Use Value: Dual event detect inputs (EVHS/EVLS) directly interface with contact sensors and motion detectors, eliminating external GPIO expanders.

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
MCP795W11T-I/ST	No 32 kHz boot-up clock; identical SRAM, EEPROM, alarms, and trimming.	Lacks power-up clock assertion on CLKOUT/BOOT - requires host firmware to initialize clock output.	Select when boot-time clock output is unnecessary and cost optimization is prioritized.
DS3231M+	Integrated TCXO (±2 ppm accuracy), higher VCC min (2.3V), no EUI-48™ ID, I²C interface only.	Superior temperature stability but incompatible SPI interface and lacks event detect inputs or boot-clock feature.	Select when absolute accuracy over temperature is critical and I²C is preferred; not drop-in compatible.

Compared with MCP795W11T-I/ST, the MCP795B11T-I/ST adds guaranteed 32 kHz boot-up clock functionality without increasing footprint or supply requirements; compared with DS3231M+, it trades ±2 ppm TCXO stability for SPI compatibility, dual event inputs, and EUI-48™ identity - making it better suited for cost-sensitive, firmware-light, or event-driven embedded designs.

Availability

MCP795B11T-I/ST is available at Aetrix Electronics and suitable for industrial metering, medical device logging, building automation, and backup-critical embedded systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MCP795B11T-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 MCP795XXX product line delivers highly integrated SPI real-time clock/calendars with battery switchover, nonvolatile memory, and system-level peripherals (WDT, event detect) for resource-constrained embedded applications needing robust timekeeping and data integrity.

FAQ

What is the function of the CLKOUT/BOOT pin on the MCP795B11T-I/ST?

The CLKOUT/BOOT pin on the MCP795B11T-I/ST serves a dual role: as a programmable clock output (1 Hz, 4.096 kHz, 8.192 kHz, or 32.768 kHz) during normal operation, and as an automatic 32 kHz boot-up clock source asserted immediately after power-on reset - a feature exclusive to the MCP795BXX series. This eliminates host firmware delays in establishing a stable timebase.

Does the MCP795B11T-I/ST support battery-backed SRAM and EEPROM simultaneously?

Yes, the MCP795B11T-I/ST supports concurrent battery-backed operation of both 64-byte SRAM and 1 Kbit EEPROM during VCC loss. When VCC drops below the switchover threshold (1.3–1.7V), the internal power sense circuit automatically connects VBAT to retain RTCC registers, SRAM contents, and EEPROM state - all while maintaining <700 nA quiescent current at 1.8V VBAT.

How does the power-fail time-stamp feature work in the MCP795B11T-I/ST?

The MCP795B11T-I/ST hardware monitors VCC and logs timestamps automatically upon power failure (VCC drop below 1.3–1.7V) and power restoration (VCC rise above threshold). These timestamps are stored in dedicated registers (0x18–0x1F) within the RTCC memory map and remain accessible via SPI after recovery - enabling precise outage duration measurement without host CPU intervention.

Is the EUI-48™ unique ID in the MCP795B11T-I/ST factory-programmed or user-programmable?

The EUI-48™ unique ID in the MCP795B11T-I/ST is factory-programmed and resides in a protected 128-bit EEPROM area. It is delivered preprogrammed and locked; users may unlock and reprogram it only after executing the UNLOCK instruction (0x14) followed by IDWRITE (0x32), subject to security constraints defined in the datasheet - ensuring MAC address integrity in certified deployments.

What are the key differences between MCP795B11T-I/ST and MCP795W11T-I/ST?

The core difference is the 32 kHz boot-up clock: MCP795B11T-I/ST asserts 32.768 kHz on CLKOUT/BOOT at power-on, while MCP795W11T-I/ST does not. Both share identical SRAM (64 B), EEPROM (1 Kbit), alarms, trimming, and package. No other functional or electrical differences exist - making MCP795B11T-I/ST the choice when immediate clock availability is required.

MCP795B11T-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:: Obsolete

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 ~ 5.5V

Voltage - Supply, Battery:: 1.3V ~ 5.5V

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

MCP795B11T-I/ST FAQ

1.How can I place an order for MCP795B11T-I/ST through Aetrix?

Please submit a Request for Quotation (RFQ) for MCP795B11T-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 MCP795B11T-I/ST reliable?

The price and inventory of MCP795B11T-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 MCP795B11T-I/ST is usually 5 days.

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MCP795B11T-I/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MCP795B11T-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 MCP795B11T-I/ST?

For technical support, including MCP795B11T-I/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MCP795B11T-I/ST requirements.

6.How does Aetrix verify that MCP795B11T-I/ST is sourced from the original manufacturer or authorized distributors?

All MCP795B11T-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 MCP795B11T-I/ST meets industry standards.

7.What is the process for return or replacement of MCP795B11T-I/ST?

All MCP795B11T-I/ST units undergo pre-shipment inspection (PSI). If there is an issue with MCP795B11T-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 MCP795B11T-I/ST part is unused and in its original packaging.

Return procedure for MCP795B11T-I/ST:

1.Submit a request within 90 days.

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

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