8051 8-bit MCU, Full Speed USB, 40kB Flash, 3kB RAM, 5 Volt, 12-bit ADC, UART, SMBus, SPI, 13 GPIOs

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Part #:
Lead Time 6 weeks
Unit Price:$1.22
Minumum Qty: 2500
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The EFM8 Universal Bee 3 or UB3 is a full speed USB 2.0 MCU with a large set of integrated peripherals.  It reduces the BOM cost of USB system with integrated oscilator, dead battery support, low power modes, and more.  The UB3 is an 8051 8-bit MCU with 40kB flash, 3kB of RAM, 12-bit ADC, 6 timers, configurable logic units, and many more peripherals.
The EFM8UB3, part of the Universal Bee family of MCUs, is a multi-purpose line of 8-bit microcontrollers with USB feature set in small packages. These devices offer high value by integrating an innovative energy-smart USB peripheral interface, charger detect circuit, 8 kV ESD protection, and enhanced high speed communication interfaces into small packages, making them ideal for space-constrained USB applications. With an efficient 8051 core and precision analog, the EFM8UB3 family is also optimal for embedded applications.


  • Pipelined 8-bit C8051 core with 48 MHz maximum operating frequency
  • Up to 17 multifunction I/O pins
  • Low Energy USB with full- and low-speed support saves up to 90% of the USB energy
  • USB charger detect circuit (USB-BCS 1.2 compliant)
  • One 12-bit ADC and two analog comparators with internal voltage DAC as reference input
  • Six 16-bit timers
  • UART and SMBus master/slave
  • Priority crossbar for flexible pin mapping


EFM8UB3 applications include the following: 

  • USB I/O controls
  • Docking stations/USB hubs
  • Dongles
  • Consumer electronics
  • USB Type-C converters
  • USB Type-C billboard/alternate mode


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