June 2013

DocID023194 Rev4

1/17

AN4111

Application note

BAL-NRF01D3 matched balun with integrated harmonics filter for

Nordic Semiconductor ultralow power transceivers

Introduction

The nRF24LE1, nRF24AP2, nRF51422 and nRF51822 QFN from Nordic Semiconductor

are 2.45 GHz combo chips with an ultralow power transceiver.

The BAL-NRF01D3 from STMicroelectronics is an ultra miniature balun for which the

matching impedance has been customized for the nRF24LE1 QFN-32, nRF24AP2-1CH,

nRF24AP2-8CH, nRF51422-QFAA, and nRF51822-QFAA Nordic Semiconductor circuits.

The BAL-NRF01D3 integrates matching network and harmonics filters. It uses

STMicroelectronics’ IPD technology on non-conductive glass substrate which optimizes RF

performance.

Compared to traditional discrete solutions (Figure 3), STMicroelectronics BAL-NRF01D3

decreases the BOM count by 80%, from 5 components to 1 component (Figure 4). This

results in a lower system cost solution.

The BAL-NRF01D3 has been tested and approved by Nordic Semiconductor in the

nRF2723 nRFgo module (from the nRFgo nRF24LE1 QFN-32 pins development kit) and the

nRF2752 nRFgo module (from the nRFgo nRF51x22 Developer Preview kit). The

BAL-NRF01D3 demonstrates a higher system performance compared to traditional

solutions. This document presents the test and performance results.

www.st.com