MCP795B11-I/SL

Real Time Clock Overview

The MCP795B11-I/SL is a low-power Real-Time Clock/Calendar (RTCC) from Microchip Technology, featuring an SPI interface. It includes 64 bytes of battery-backed SRAM and 1 Kbit of EEPROM with preprogrammed EUI-48™ Unique ID. Key electrical parameters include a VCC operating range of 1.8V to 5.5V and a VBAT range of 1.3V to 5.5V. Standby current is less than 1µA at 3V, while timekeeping current on VBAT is under 700nA at 1.8V. The device supports industrial temperature operation (-40°C to +85°C) and provides features such as programmable alarms, watchdog timer, event detection, and automatic battery switchover.

Real Time Clock Feature Summary

• Integrated 1 Kbit EEPROM with preprogrammed EUI-48™ MAC address and 64-byte battery-backed SRAM.
• Supports 32 kHz boot-up clock output at power-up via the CLKOUT/BOOT pin.
• Features digital trimming/calibration with a +/- 255 PPM range in 1 PPM steps for accuracy.
• Includes dual configurable event detect inputs (EVHS/EVLS) and a programmable watchdog timer.

Real Time Clock Applications

• Smart energy devices such as thermostats and power meters.
• Home appliances including coffee makers and microwave ovens.
• Automotive dashboard controls and GPS systems.
• Consumer electronics like office equipment and video systems.

Real Time Clock Procurement Notes

Verify the package suffix 'SL' corresponds to the TSSOP-14 form factor, as datasheet documentation primarily references SOIC/TSSOP generic designations. Confirm that the specific revision matches the preliminary DS22280A specifications regarding the 32 kHz boot feature unique to the BXX series. Ensure compatibility with the required external 32,768 kHz tuning fork crystal and load capacitors for oscillator operation.

Real Time Clock Selection Notes

Select this model over the WXX series if a 32 kHz clock output at power-up is required for system initialization. The '11' designation indicates 1 Kbit EEPROM capacity; choose '21' variants if 2 Kbit storage is needed. Verify that the preprogrammed EUI-48™ ID meets network identification requirements, or select 'Blank' variants if custom programming is preferred. Ensure the SPI interface speed up to 10 MHz aligns with the master controller's capabilities.

Real Time Clock Part Context

This component belongs to the MCP795WXX/MCP795BXX family of stand-alone RTCC devices. The 'B' prefix distinguishes it from the 'W' series by adding the 32 kHz boot-up clock capability. The 'I' suffix denotes the Industrial temperature grade (-40°C to +85°C). These devices are designed to reduce component counts in applications requiring accurate timekeeping and non-volatile data storage with minimal power consumption.

Real Time Clock Replacement Considerations

Public confirmed substitute part numbers: MCP795B11-I/ST (SOIC-14 package variant), MCP795B11T-I/SL (Tape & Reel packaging variant).

Real Time Clock FAQ

What is the function of the CLKOUT/BOOT pin on the MCP795B11?

On MCP795BXX devices, the CLKOUT/BOOT pin provides a 32 kHz clock output specifically at power-up. Under normal operation, it functions as a programmable square wave output (1Hz, 4.096kHz, 8.192kHz, or 32.768kHz).

How does the device handle power failure?

The device features an automatic battery switchover circuit. When VCC drops below the trip voltage (typically 1.5V), it switches to VBAT to maintain timekeeping and SRAM retention. It also logs power-down and power-up timestamps to calculate failure duration.

What memory types are included in the MCP795B11?

It contains 64 bytes of battery-backed SRAM for user data and 1 Kbit of Serial EEPROM. The EEPROM includes a protected 128-bit area preprogrammed with an EUI-48™ Unique ID.