MCP795B21T-I/ST

Real Time Clock Overview

The MCP795B21T-I/ST is a low-power Real-Time Clock/Calendar (RTCC) with SPI interface, housed in a 14-lead TSSOP package. It features a 32 kHz boot-up clock at power-up, 64 bytes of battery-backed SRAM, and 2 Kbit of EEPROM with a preprogrammed EUI-48™ MAC address. Operating from 1.8V to 5.5V on VCC and 1.3V to 5.5V on VBAT, it supports automatic battery switchover. Key specifications include an industrial temperature range (-40°C to +85°C), up to 10 MHz SPI clock speed, dual programmable alarms, and on-chip digital trimming for ±255 PPM calibration.

Real Time Clock Feature Summary

• Integrated 32 kHz Boot-up Clock output at power-up via CLKOUT/BOOT pin
• 2 Kbit EEPROM with preprogrammed EUI-48™ Unique ID and 64-byte Battery-Backed SRAM
• Dual Configurable Event Detect inputs (EVHS/EVLS) and Programmable Watchdog Timer
• Automatic Battery Switchover with Power-Fail Time-Stamp logging

Real Time Clock Applications

• Systems requiring millisecond-level alarm precision via high-speed SPI
• Network devices utilizing the preprogrammed EUI-48™ MAC address for identification
• Industrial applications needing robust watchdog timing independent of the main microcontroller
• Battery-powered systems requiring precise timekeeping during main power loss

Real Time Clock Procurement Notes

Verify that the 'I' suffix confirms the Industrial temperature grade (-40°C to +85°C) and the 'ST' suffix corresponds to the 14-TSSOP package. Confirm the '21' designation ensures the inclusion of the 2 Kbit EEPROM array and the specific EUI-48™ unique ID implementation as documented in the device selection table.

Real Time Clock Selection Notes

Select this variant over the MCP795W21T-I/ST specifically when a 32 kHz clock signal is required immediately upon power-up without waiting for oscillator stabilization. Ensure the application utilizes an SPI interface compatible with the specified voltage levels. The preprogrammed EUI-48™ ID eliminates the need for user programming if network addressing is required.

Real Time Clock Part Context

This component belongs to the MCP795BXX family, distinguished by the 'B' indicating the presence of the 32 kHz boot-up clock feature. It shares the same memory architecture and enhanced event detection capabilities as the W-series but adds the boot-time clock output functionality on the CLKOUT/BOOT pin for immediate system synchronization.

Real Time Clock Replacement Considerations

The MCP795W21T-I/ST is a functional substitute if the 32 kHz boot-up clock feature is not required. Both share identical memory maps, SPI interfaces, and package types.