Replace balun and filter with integrated balun We consider the balun needs for the AT86RF230 and the TI/Chipcon CC2520 we may try as a design alternative. For the AT86RF230, Atmel recommend baluns with integrated filter, namely the Wuerth 748421245 and the Johanson 2450FB15L0001, both in the AR86RF230 data sheet. For the CC2520, TI recommend a microstrip-based design for the balun, both in the CC2420/CC243x/CC2480 application note [1] and the reference design [2], without fully characterizing neither the transceiver's RF output nor all the components in the balun. Johanson lists the 2450FB15L0001 [3] and even a 2450BM15B0002 [3] for the TI/Chipcon CC2520, but not even Octoparts is able to find a distributor for these parts. Digging deeper, TI reveal more information about the balun in [5]. Finally, TI somewhat hesitatingly acknowledge that the Murata balun LDB182G4510C-110 can be used for the CC2520 [6], with a 3.9 nH inductor connecting RF_P and RF_N, the balun coupled to GND not directly but via 10 nF, and finally an LC low-pass filter with 1.5 nH and 2.2 pF at the output, for EMI compliance. Note that this also means that CC2520 and AT86RF230 both have an impedance of 100 Ohm. A balun without filter similar to the Murata part would be the Johanson 2450BL15K100. Manufacturer Part number Package Digi-Key Price/Qty --------------- ----------------------- ------- --------------- --------------- Wuerth 748421245 0805-6 732-2230-1-ND 2.15/25 732-2230-2-ND 0.753/4000 Johanson 2450FB15L0001 0805-6 - - Johanson 2450BM15B0002 0805-6 - - Johanson 2450BL15K100 0805-6 712-1045-1-ND 0.488/10 712-1045-2-ND 0.225/4000 Murata LDB182G4510C-110 0603-6 490-5023-1-ND 0.325/10 490-5023-2-ND 0.114/4000 [1] http://www.ti.com/litv/pdf/swra098d [2] http://focus.ti.com/docs/toolsw/folders/print/cc2520em_refdes.html [3] http://www.johansontechnology.com/images/stories/ip/baluns/Balun_Filter_Combo_Matched_2450FB15L0001_v11.pdf [4] http://www.johansontechnology.com/images/stories/ip/baluns/balun_filter_combo_matched_2450bm15b0002_v2.pdf [5] http://www.ti.com/litv/pdf/swra236a [6] http://e2e.ti.com/support/low_power_rf/f/155/t/15910.aspx Conclusion: the Wurth balun appears to be the safest choice for prototyping the AT86RF230. Due to its high cost, a circuit with a discrete filter may be considered for larger quantities. For the CC2520, it's probably safest to directly try the Muarta balun with the recommended discrete filtering circuit.