Microchip Technology MCP795B12T-I/SL

Overview

MCP795B12T-I/SL from Microchip Technology is a SPI-interfaced real-time clock/calendar (RTCC) IC with battery-backed SRAM, 1 Kbit EEPROM, EUI-64™ unique ID, and integrated 32 kHz boot-up clock. It delivers timekeeping accuracy via digital trimming (±255 ppm in 1 ppm steps), supports dual programmable alarms with IRQ/WDO outputs, and operates from 1.8V–5.5V VCC or 1.3V–5.5V VBAT for continuous timekeeping during main power loss - used in industrial metering, backup power systems, and embedded data loggers.

For engineers reviewing the MCP795B12T-I/SL datasheet, MCP795B12T-I/SL pinout, MCP795B12T-I/SL application, or MCP795B12T-I/SL equivalent, key selection criteria include its 32 kHz boot-up capability, VBAT switchover voltage threshold (1.3–1.7 V), <700 nA timekeeping current at 1.8 V, 10 MHz SPI interface, and EUI-64™ preprogrammed ID support.

Technical Context

This RTCC integrates a crystal oscillator interface (32.768 kHz tuning fork), on-chip digital calibration logic, and dual event detect inputs (EVHS/EVLS) with programmable debounce and pulse counting. Its power-fail time-stamp function logs both VCC dropout and restoration timestamps in dedicated registers (0x18–0x1F).

The device implements a 10 MHz SPI master-slave interface with MSb-first protocol, supports page writes up to 8 bytes in EEPROM, and features a hardware watchdog timer with dedicated WDO pin and dual retrigger sources (SPI command or EVHS input).

Key Specifications

Pinout & Package

Package: 14-lead SOIC (Small Outline Integrated Circuit), 3.9 mm × 8.7 mm body, 1.27 mm pitch, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar real-time clock/calendar applications.

Compared with MCP795B12T-I/SL, MCP795B11T-I/SL trades EUI-64™ for EUI-48™ at identical cost and power profile, while MCP795W12T-I/SL omits the critical 32 kHz boot clock - making MCP795B12T-I/SL the sole choice for fail-safe time initialization in safety-critical or zero-delay wake-up systems.

Availability

MCP795B12T-I/SL is available at Aetrix Electronics and suitable for industrial metering, medical data logging, and POS terminal applications requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for MCP795B12T-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, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The MCP795XXX family was designed specifically for embedded systems requiring autonomous, battery-backed timekeeping with integrated memory, event detection, and watchdog functionality - targeting industrial, medical, and utility applications demanding high reliability and low power.

FAQ

What is the primary function of the MCP795B12T-I/SL?

The MCP795B12T-I/SL is a SPI real-time clock/calendar IC with integrated 64-byte battery-backed SRAM, 1 Kbit EEPROM, EUI-64™ unique ID, and 32 kHz boot-up clock. Its primary function is to maintain accurate time and date across main power loss using automatic VCC-to-VBAT switchover, while supporting alarms, event detection, and timestamped logging - all within a single 14-pin SOIC package.

Does the MCP795B12T-I/SL require an external crystal?

Yes, the MCP795B12T-I/SL requires an external 32.768 kHz tuning fork crystal connected between X1 and X2 pins to operate its internal oscillator. The device does not include an integrated resonator. However, it supports external CMOS clock input via X1 if the EXTOSC bit (Register 0x08, bit 3) is set, bypassing the crystal requirement.

What is the significance of the "B" in MCP795B12T-I/SL?

The "B" in MCP795B12T-I/SL denotes the presence of the 32 kHz boot-up clock feature on the CLKOUT/BOOT pin at power-on reset. This distinguishes it from the "W" variant (e.g., MCP795W12T-I/SL), which lacks this immediate clock output and requires software configuration to enable CLKOUT functionality.

How does the power-fail time-stamp feature work in the MCP795B12T-I/SL?

The MCP795B12T-I/SL automatically logs the time of VCC failure and restoration into dedicated registers (0x18–0x1F). When VCC drops below the switchover threshold (1.3–1.7 V), the VBAT bit (Register 0x04, bit 4) is set and the current time is written to power-down registers. Upon VCC return, the time is captured again in power-up registers - enabling precise outage duration calculation without host intervention.

Can the MCP795B12T-I/SL operate solely from VBAT without VCC applied?

Yes, the MCP795B12T-I/SL can maintain timekeeping and SRAM retention using only VBAT (1.3V–5.5V) when VCC is absent, provided the VBATEN bit (Register 0x04, bit 3) is set. However, SPI communication, EEPROM writes, and alarm/event processing require VCC; only the RTCC core and SRAM remain functional under VBAT-only operation.