MCP795B20-I/ST

Real Time Clock Overview

The MCP795B20-I/ST is a low-power Real-Time Clock/Calendar (RTCC) manufactured by Microchip Technology. It features an integrated watchdog timer, two programmable alarms, and digital trimming for accuracy. The device supports SPI communication with clock speeds up to 10 MHz. Key specifications include a wide operating voltage range of 1.8V to 5.5V for VCC and 1.3V to 5.5V for the backup supply (VBAT). It includes 64 bytes of battery-backed SRAM, 2 Kbit of EEPROM, and a 128-bit unique ID area. The 'B' suffix indicates support for a 32 kHz boot-up clock output at power-on.

Real Time Clock Feature Summary

• Real-Time Clock/Calendar with automatic leap year correction and 12/24-hour format options.
• Integrated Watchdog Timer with dedicated output pin and dual retrigger capability via SPI or EVHS input.
• Dual Configurable Event Detect Inputs: High-Speed (EVHS) with pulse counting and Low-Speed (EVLS) with debounce.
• Power-Fail Time-Stamp functionality logs time during VCC failure and restoration.

Real Time Clock Applications

• Systems requiring precise timekeeping with millisecond alarm resolution.
• Applications needing independent watchdog monitoring outside the main microcontroller.
• Devices utilizing event detection for hardware interrupt generation based on external pulses.
• Battery-powered systems requiring automatic switchover between main and backup supplies.

Real Time Clock Procurement Notes

Verify the package type corresponds to the '/ST' suffix, which denotes a 14-Lead TSSOP. Confirm the temperature grade 'I' matches industrial requirements (-40°C to +85°C). Ensure the specific memory configuration (2 Kbit EEPROM, Blank ID) aligns with the '20' designation in the part number. Cross-reference the datasheet DS22280A for final electrical parameters before integration.

Real Time Clock Selection Notes

Select this component when SPI interface speed up to 10 MHz is required for RTCC data access. Choose the MCP795BXX variant over the WXX series if a 32 kHz clock output at power-up is necessary. Consider the built-in watchdog and event detect features if system robustness against software hangs or external signal monitoring is critical. Ensure external load capacitors are selected to match the crystal oscillator requirements.

Real Time Clock Part Context

This device belongs to the MCP795WXX/MCP795BXX family of RTCCs. The 'B' variant specifically enables the CLKOUT/BOOT pin to output a 32 kHz signal immediately upon power-up, utilizing the same crystal as the timekeeping oscillator. The '20' suffix indicates 2 Kbit EEPROM capacity and a blank Unique ID area. The '-I/ST' suffix specifies Industrial temperature range and 14-pin TSSOP packaging.

Real Time Clock Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation. When evaluating alternatives, ensure compatibility with SPI protocol, voltage ranges (1.8V-5.5V), and package dimensions (14-TSSOP). Verify that replacement devices offer similar non-volatile memory sizes and event detection capabilities if those features are utilized in the design.