NXP – New wireless MCUs can run Bluetooth Low Energy and Thread stacks concurrently


NXP Semiconductors’ latest Kinetis W series MCUs provide multi-protocol networking operation in a single chip. Capable of concurrently running two 2.4GHz radio protocols – Bluetooth® Low Energy (LE) v4.2 and IEEE 802.15.4 Thread stacks – the Kinetis KW41Z, KW31Z and KW21Z enable designers to implement sophisticated wireless capabilities in space- constrained systems.

There are three MCUs in the new series. They share the same features and specifications, but support different radio protocols:
• KW41Z supports Bluetooth LE, Generic Frequency Shift Keying (FSK) and IEEE 802.15.4 Thread
• KW31Z supports Bluetooth LE and Generic FSK
• KW21Z supports 802.15.4 Thread and Simple MAC

Based on the ARM® Cortex®-M0+ core, they offer up to 512kbytes of Flash and up to 128kbytes of SRAM, sufficient to store the networking stacks while leaving ample room for user applications.

The MCUs are notable for their very low- power radio and stand-by power consumption.

Receive current is 6.8mA and Transmit current is 6.1mA. An integrated buck-boost DC-DC converter operates from an input range of 0.9V to 4.2V, which means that it is compatible with a wide range of batteries, from single alkaline or coin cells to lithium-ion rechargeable batteries.

The KWx1Z series is an excellent solution for designs that require concurrent Bluetooth LE and Thread communication. This multi-mode capability enables direct communication using Bluetooth LE via a mobile device or tablet, and communication in a mesh network for local and remote control and monitoring.

The new MCUs can therefore enable designers to:
• replace several MCUs and radios with a single MCU
• reduce bill-of-materials cost
• reduce system complexity
• realise a more integrated system
• extend battery run-time between charges


  • 95dBm sensitivity in Bluetooth LE mode
  • -100dBm sensitivity in generic FSK mode at 250kbits/s
  • -100dBm sensitivity in 802.15.4 mode
  • +3.5dBm maximum Transmit power
  • AES-128 cryptographic accelerator
  • On-chip balun with single-ended bi-directional RF port
  • 16-bit ADC, 12-bit DAC


  • Access-control systems
  • Curtain and blind controls
  • Intruder alarms
  • Lighting controls
  • Smart thermostats
  • Wearable devices
  • Patient monitoring equipment
  • Metering and home energy gateways
  • Building-automation systems
  • Asset tracking

Orderable Part Numbers: FRDM-KW41Z and USB-KW41Z