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

Microchip Technology MCP795B22-I/SL

Name: MCP795B22-I/SL
Brand: Microchip Technology
SKU: MCP795B22-I/SL
Price: 2.40 USD
Availability: InStock
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Part No.:: MCP795B22-I/SL

Manufacturer:: Microchip Technology

Category:: Real Time Clocks

Package:: 14-SOIC (0.154", 3.90mm Width)

Datasheet:: MCP795B22-I/SL.pdf

Description:: IC RTC CLK/CALENDAR SPI 14SOIC

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Product details

Overview

MCP795B22-I/SL from Microchip Technology is a SPI real-time clock/calendar (RTCC) IC with integrated 64-byte battery-backed SRAM, 2 Kbit EEPROM, EUI-64™ unique ID, and 32 kHz boot-up clock capability. It delivers accurate timekeeping (hours/minutes/seconds/hundredths/day/month/year/leap year), dual programmable alarms, digital trimming (±255 ppm in 1 ppm steps), and power-fail time-stamping - all operating from 1.8V–5.5V VCC or 1.3V–5.5V VBAT, targeting industrial metering and backup-critical embedded systems.

For engineers reviewing the MCP795B22-I/SL datasheet, MCP795B22-I/SL pinout, MCP795B22-I/SL application, or MCP795B22-I/SL equivalent, key selection criteria include its 32 kHz boot-up clock on CLKOUT/BOOT, VBAT switchover at 1.3–1.7 V, <700 nA timekeeping current at 1.8 V, 10 MHz SPI interface, and support for high-speed (EVHS) and low-speed (EVLS) event detection with debounce.

Technical Context

The MCP795B22-I/SL implements a crystal-based RTCC architecture using an external 32.768 kHz tuning fork crystal on X1/X2, with internal digital trimming compensation and automatic oscillator start-up. Its 32 kHz boot-up clock is generated directly from the same crystal during power-up via the CLKOUT/BOOT pin - a feature exclusive to the MCP795BXX variant family.

It integrates dual event detect inputs: EVHS supports pulse counting (1st/4th/16th/32nd edge) with VCC/VBAT operation, while EVLS provides programmable 31 ms or 500 ms debounce for mechanical switch interfaces. The watchdog timer features dedicated WDO output, dual retrigger (SPI or EVHS), and user-selectable pulse duration.

Key Specifications

Parameter	Value and Actual Design Meaning
VCC Range	1.8V to 5.5V - supports wide-input industrial power rails and direct connection to 3.3V or 5V microcontrollers.
VBAT Range	1.3V to 5.5V - enables reliable timekeeping and SRAM retention down to single-cell lithium or coin-cell backup voltage.
Timekeeping Current	<700 nA at 1.8V VBAT - extends battery life beyond 10 years in typical coin-cell backup configurations.
SPI Clock Speed	Up to 10 MHz - allows sub-millisecond alarm latency and fast register/SRAM/EEPROM access in high-throughput systems.
Calibration Range	±255 ppm in 1 ppm steps - enables field-adjustable accuracy without hardware modification or crystal replacement.
Alarm Resolution	Alarm 1 supports hundredths-of-second resolution - suitable for precision timestamping and short-interval scheduling.
Power-Fail Time-Stamp	Logs exact time of VCC failure and restoration - critical for forensic logging in utility meters and data loggers.

Pinout & Package

Package: 14-Lead SOIC (Small Outline Integrated Circuit), surface-mount, industry-standard footprint compatible with automated assembly.

Pin/Terminal	Circuit Role	Design Meaning
VSS	Ground reference	Common return path for all analog/digital circuits; must be low-impedance for RTC stability.
X1	Clock input	Connects to one terminal of external 32.768 kHz crystal; drives internal oscillator circuit.
X2	Clock output	Connects to other crystal terminal; completes Pierce oscillator loop with internal capacitance.
VBAT	Backup supply	Provides continuous power to RTC registers and SRAM when VCC drops below 1.3–1.7 V switchover threshold.
VCC	Main supply	Primary power source (1.8–5.5 V); powers full functionality including SPI, EEPROM writes, and alarms.
SI	SPI data input	Latches instruction/address/data on rising SCK edge; supports standard SPI master communication.
WDO	Watchdog output	Open-drain N-channel output requiring external pull-up; pulses low on watchdog timeout per configuration.
SCK	SPI clock	Synchronizes all serial transfers; rising edge latches SI, falling edge updates SO.
CLKOUT/BOOT	Configurable clock output	Push-pull output delivering 1 Hz / 4.096 kHz / 8.192 kHz / 32.768 kHz - or 32 kHz boot clock on power-up (MCP795BXX only).
CS	Chip select	Active-low enable; places device in standby when high, forces high-impedance SO for bus sharing.
IRQ	Interrupt output	Shared open-drain output for alarms and event detects; requires external pull-up to VCC or VBAT.
EVHS	High-speed event input	Detects rising/falling edges; counts 1st/4th/16th/32nd pulse before asserting IRQ - ideal for RPM or pulse-width measurement.
EVLS	Low-speed event input	Edge-triggered with 31 ms or 500 ms software-selectable debounce - suppresses contact bounce in pushbutton or relay interfaces.
SO	SPI data output	Shifts out register/SRAM/EEPROM data after falling SCK edge; tri-states when CS is high.

Key Features

Feature	Design Value
32 kHz Boot-Up Clock	Guarantees immediate timing reference at power-on without waiting for crystal stabilization - eliminates startup delay in fail-safe systems.
Dual Event Detect Inputs	EVHS + EVLS provide simultaneous high-precision and noise-immune signal capture - reduces need for external debouncing circuitry or firmware polling.
Power-Fail Time-Stamp	Automatically logs timestamps at VCC loss and recovery - enables precise outage duration calculation without host MCU intervention.
EUI-64™ Unique ID	Factory-programmed 128-bit identifier stored in protected EEPROM - supports secure device authentication and network addressing in IoT deployments.
On-Chip Digital Trimming	Software-adjustable ±255 ppm calibration compensates for crystal aging, temperature drift, and PCB parasitics - avoids costly external trimmer capacitors.

Applications

Smart Energy Metering	Industrial Data Logger
Use Scenario: Utility-grade electricity meter recording consumption with tariff switching and outage reporting. IC Role / Device Role / Timing Role: Primary timebase for energy integration, calendar-driven tariff changes, and power-loss event logging. Use Value: 32 kHz boot-up clock ensures immediate time validity post-power-cycle; power-fail timestamping enables accurate outage duration reporting required by regulatory standards.	Use Scenario: Ruggedized environmental sensor node logging temperature, humidity, and vibration over months on battery. IC Role / Device Role / Timing Role: Low-power timekeeper synchronizing sampling intervals and timestamping each recorded data point. Use Value: <700 nA VBAT current extends 10+ year coin-cell life; EUI-64™ ID enables unambiguous device identification across large-scale deployments.
Medical Infusion Pump	Building Automation Controller
Use Scenario: Safety-critical infusion system tracking delivery duration, dose history, and maintenance schedules. IC Role / Device Role / Timing Role: Tamper-resistant real-time clock maintaining audit trail and alarm timing even during main power interruption. Use Value: Battery-switchover preserves SRAM and RTC state during AC dropout; dual alarms trigger dose alerts and service reminders with hundredths-of-second precision.	Use Scenario: HVAC controller managing zone scheduling, occupancy-based lighting, and energy reporting. IC Role / Device Role / Timing Role: Central time source coordinating event triggers, daylight savings adjustment, and historical data archiving. Use Value: EVLS input debounces mechanical thermostat switches; 2 Kbit EEPROM stores configuration and firmware update metadata with 1M write cycles endurance.

Smart Energy Metering

Industrial Data Logger

Use Scenario: Utility-grade electricity meter recording consumption with tariff switching and outage reporting.

IC Role / Device Role / Timing Role: Primary timebase for energy integration, calendar-driven tariff changes, and power-loss event logging.

Use Value: 32 kHz boot-up clock ensures immediate time validity post-power-cycle; power-fail timestamping enables accurate outage duration reporting required by regulatory standards.

Use Scenario: Ruggedized environmental sensor node logging temperature, humidity, and vibration over months on battery.

IC Role / Device Role / Timing Role: Low-power timekeeper synchronizing sampling intervals and timestamping each recorded data point.

Use Value: <700 nA VBAT current extends 10+ year coin-cell life; EUI-64™ ID enables unambiguous device identification across large-scale deployments.

Medical Infusion Pump

Building Automation Controller

Use Scenario: Safety-critical infusion system tracking delivery duration, dose history, and maintenance schedules.

IC Role / Device Role / Timing Role: Tamper-resistant real-time clock maintaining audit trail and alarm timing even during main power interruption.

Use Value: Battery-switchover preserves SRAM and RTC state during AC dropout; dual alarms trigger dose alerts and service reminders with hundredths-of-second precision.

Use Scenario: HVAC controller managing zone scheduling, occupancy-based lighting, and energy reporting.

IC Role / Device Role / Timing Role: Central time source coordinating event triggers, daylight savings adjustment, and historical data archiving.

Use Value: EVLS input debounces mechanical thermostat switches; 2 Kbit EEPROM stores configuration and firmware update metadata with 1M write cycles endurance.

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
MCP795W22-I/SL	Lacks 32 kHz boot-up clock on CLKOUT/BOOT; otherwise identical SRAM, EEPROM, EUI-64™, and feature set.	Not suitable where immediate post-power-on timing is required; acceptable where crystal stabilization delay is tolerable.	Select MCP795W22-I/SL only if boot-clock functionality is unnecessary and cost optimization is prioritized.
DS3231SN#T&R	Includes integrated TCXO (±2 ppm accuracy), higher VCC min (2.3V), no EVHS/EVLS inputs, no boot clock, different pinout (16-pin SOIC).	Better long-term accuracy but lacks event detection and boot clock; requires redesign for pin compatibility and power domain handling.	Choose DS3231SN#T&R only when ultra-high accuracy outweighs need for integrated event inputs and boot-clock simplicity.

Compared with MCP795W22-I/SL, the MCP795B22-I/SL adds guaranteed 32 kHz clock availability at power-up - eliminating design risk from crystal start-up delay. Against DS3231SN#T&R, it trades absolute accuracy for integrated event detection, lower VCC minimum, and seamless SPI compatibility - reducing BOM count and layout complexity in resource-constrained systems.

Availability

MCP795B22-I/SL is available at Aetrix Electronics and suitable for smart metering, industrial data logging, medical device timing, building automation, and battery-backed instrumentation requiring stable component supply across extended product lifecycles.

Supply support for MCP795B22-I/SL 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, low-power real-time clock/calendars with embedded memory and system-level peripherals - designed specifically for applications demanding robust timekeeping, event-awareness, and seamless backup power operation in harsh or power-unstable environments.

FAQ

What is the primary function of the MCP795B22-I/SL?

The MCP795B22-I/SL is a SPI real-time clock/calendar IC that maintains accurate time and date (including leap year correction), provides dual alarms, battery-backed SRAM and EEPROM storage, EUI-64™ unique identification, and a 32 kHz boot-up clock. Its core role is to serve as a self-contained, low-power timing and data-logging engine in embedded systems where main power may be intermittent.

Does the MCP795B22-I/SL require an external crystal?

Yes, the MCP795B22-I/SL requires an external 32.768 kHz tuning fork crystal connected between X1 and X2 pins to operate its real-time clock. It does not include an integrated oscillator. However, it supports an optional external CMOS clock signal applied to X1 (with X2 left unconnected) as an alternative timing source.

What distinguishes the MCP795B22-I/SL from the MCP795W22-I/SL?

The key distinction is the 32 kHz boot-up clock: the MCP795B22-I/SL asserts a stable 32.768 kHz square wave on the CLKOUT/BOOT pin immediately at power-up, while the MCP795W22-I/SL does not. Both share identical SRAM, EEPROM, EUI-64™, alarms, event inputs, and calibration features - making the "B" variant essential for systems requiring instant timing validity.

How does the power-fail time-stamp feature work in the MCP795B22-I/SL?

When VCC drops below the 1.3–1.7 V switchover threshold, the MCP795B22-I/SL automatically logs the current time into dedicated Power-down Time-stamp registers (addresses 0x18–0x1B). Upon VCC restoration, it records the recovery time in Power-Up Time-stamp registers (0x1C–0x1F). This occurs autonomously without host MCU involvement.

Can the MCP795B22-I/SL operate solely from VBAT without VCC present?

Yes - when VCC is absent or below the switchover threshold, the MCP795B22-I/SL continues timekeeping and retains SRAM contents using VBAT (1.3–5.5 V). However, SPI communication, EEPROM writes, and alarm generation require VCC; only basic RTC incrementing and VBAT-powered IRQ assertion (if configured) remain functional under VBAT-only operation.

MCP795B22-I/SL Specifications

Product attributes: Attribute value

Manufacturer:: Microchip Technology

Series:: -

Package/Case:: 14-SOIC (0.154", 3.90mm Width)

Packaging:: Tube

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-SOIC

MCP795B22-I/SL FAQ

1.How can I place an order for MCP795B22-I/SL through Aetrix?

Please submit a Request for Quotation (RFQ) for MCP795B22-I/SL 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 MCP795B22-I/SL reliable?

The price and inventory of MCP795B22-I/SL are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MCP795B22-I/SL is usually 5 days.

3.What payment methods are accepted for MCP795B22-I/SL?

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MCP795B22-I/SL orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MCP795B22-I/SL 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 MCP795B22-I/SL?

For technical support, including MCP795B22-I/SL datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MCP795B22-I/SL requirements.

6.How does Aetrix verify that MCP795B22-I/SL is sourced from the original manufacturer or authorized distributors?

All MCP795B22-I/SL 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 MCP795B22-I/SL meets industry standards.

7.What is the process for return or replacement of MCP795B22-I/SL?

All MCP795B22-I/SL units undergo pre-shipment inspection (PSI). If there is an issue with MCP795B22-I/SL, 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 MCP795B22-I/SL part is unused and in its original packaging.

Return procedure for MCP795B22-I/SL:

1.Submit a request within 90 days.

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

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