Low-pin-count variants added to Fujitsu's Cortex-M3-based FM3 MCUs

May 07, 2013 // By Graham Prophet

Fujitsu Semiconductor has introduced a series of 32-bit RISC microcontrollers based on the ARM Cortex-M3 processor, expanding the Fujitsu FM3 MCU family to around 500 products in total. This MCU series includes the MB9BF121JWQN model, which features low-pin-count QFN packaging and is optimised for system control in household appliances, office automation systems and industrial equipment. The MCUs announced today are part of the FM3 Family’s Basic Group, which balances performance and cost.

The MB9B120J series is the first in the FM3 family to feature 32-pin packaging. LQFP and QFN package types are offered, with dimensions starting at 5 x 5 mm. Features such as a trimmed on-chip RC oscillator and internal pull-up resistors reduce the number of external components, further shrinking the PCB footprint.

The series is available at operating speeds of up to 72 MHz, which is the ceiling for the FM3 Family’s Basic Group. Optimised peripheral functions suit this series for applications requiring low-pin inverter control. These include general-use inverters and motors for low-end industrial equipment, as well as household appliances such as refrigerators, washing machines and induction cooking appliances. The series is also ideal for devices requiring a one-to-one motor-to-microcontroller system architecture. The functional core of the inverter is the “multi-function timer”, which includes sophisticated, flexible ADC trigger configurations, pulse-width modulation (PWM) and a waveform generator with dead time insertion. The ADC features 12-bit resolution and converts 1 million samples per second.

As with all FM3 Basic Group microcontrollers, the MB9B120J series features a supply voltage range extending from 2.7 V to 5.5 V. The ability to deploy these MCUs in 5-V environments is an advantage for developers needing to consider rugged design models. Introduced in 2010, the Fujitsu FM3 MCU family also includes High Performance, Low Power and Ultra Low Leak groups. In the near future, Fujitsu is planning to expand its microcontroller portfolio with the FM4 Family of Cortex-M4-based processors and the FM0+ Family of