STMicroelectronics – Enhanced balun with integrated harmonic filter for use with BlueNRG transceivers


STMicroelectronics’ BALF-NRG-02D3 ultraminiature balun integrates a matching network with a harmonics filter in a single chip.

The matching impedance of the device is optimised for the BlueNRG series of Bluetooth® Low Energy (BLE) systems-on-chip, both the BlueNRG-1, and the more recent BlueNRG-2.


By integrating both the matching network and filter in a single component, ST reduces the complexity of the RF circuit, and provides an optimised link budget in a footprint of less than 1.2mm2. Its non-conductive glass substrate offers low dispersion over temperature, achieving superior performance to currently available products.

The device is housed in a four-bump, chip- scale package on glass measuring 1.4mm x 0.9mm.


  • 50Ω nominal input/conjugate match to BlueNRG devices
  • Low insertion loss
  • Low amplitude imbalance
  • Low phase imbalance


  • Systems with Bluetooth connectivity