Johanson Technology’s RF Front-End Solution Impedance Matched Balun Filter Integrated Passive for Nordic’s nRF8001 Chipset June 2012 1. Introduction The nRF8001 from Nordic Semiconductor is a 2.45GHz is a highly integrated single-chip Bluetooth® low energy Connectivity IC. It integrates a fully compliant Bluetooth v4.0 low energy Radio, Link Layer, and Host stack and features a simple serial interface that supports a wide range of external application microcontrollers. Johanson Technology’s, 2450BM14A0002 LPF-Balun was specifically designed for use with the nRF8001 chipset. This matched balun greatly simplifies the RF front-end by considerably reducing component count, system variability, implementation size area, and PCB sensitivity. PCB layout example shown on Figures 1a and 1b. Figures 1a and 1b. Ref, Design layout example. The 2450BM14A0002 is an SMD six-pin LTCC device with a small foot print of only 1.6mm X 0.8mm X 0.7mm (EIA 0603). Please refer to Appendix A for the datasheet of balun filter component. For more info such as gerber files, additional App Notes and specific component info go to: www.johansontechnology.com/nordic Written by: Manuel Carmona BDM/RF Engineer 1 2. Description and Schematics of Reference Designs Using LTCC integrated monolithic technology, Johanson has developed a solution with a 6-pin impedance-matched chip balun-harmonic filter integrated passive component that is especially matched for the nRF8001 IC, the 2450BM15A0002 providing necessary RF filtering (i.e. FCC, ETSI), a more reliable system, impedance controlled environment, consistency in performance, and a very small RF front end-solution compared to the L/C discrete shown in Figures 1a and 1b. Figure 2a. Discrete L/C Ref. Design solution Figure 2b. Integrated Ref. Design solution The rightmost is the JTI impedance-matched balun 2450BM14A0002. For more info such as gerber files, additional App Notes and specific component info go to: www.johansontechnology.com/nordic Written by: Manuel Carmona BDM/RF Engineer 2 3. Layout Maintain ~2mm trace length from Chipset to BalunFilter! Figure 3. Top Layer for Reference Design In the event that the reference design cannot be copied to the letter; then, the routing from the RF pins ANT1 and ANT2 must be symmetrical to the matched balun component, 2450BM14A0002. The length of the tracks should be kept to the recommended length (~2mm) and preferably the same length and width that are used in the reference design. This routing must be symmetrical. If it is not, then the output power may be reduced and the harmonics may increase. The component placement influences the RF performance. It is recommended that the reference PCB layout be copied as closely as possible. In particular, the designer should make note of all dimensions between the nRF8001 and 2450BM14A0002. To download the gerber files go to: http://johansontechnology.com/nordic 4. Measurement Results All results presented in this chapter are based on measurements performed with nRF8001 and 2450BM14A0002 Reference Design board. All measurement results presented are the average of each batch tested from typical devices. Johanson’s 2450BM14A0002 Filter - Balun offers improved suppressed 2nd and 3rd harmonics, it eases implementation and increases margin to FCC/ETSI compliance when compared to solution with discrete passives. For more info such as gerber files, additional App Notes and specific component info go to: www.johansontechnology.com/nordic Written by: Manuel Carmona BDM/RF Engineer 3 Test Name: Dev ice under test: Test engineer: Johanson Balun 2mm nRF8001 Ketil Aas-Johansen Figure 1: Fundamental Figure 2: Fundamental Hi Figure 3: Fundamental Mid Figure 4: 2nd harmonic Figure 5: 3rd harmonic Figure 6: 4th harmonic Fundamental Center Frequency [MHz] Lev el [dBm] Marker Frequency [MHz] Fundamental Hi Fundamental Mid2nd harmonic 3rd harmonic 4th harmonic 2402.00 2480.00 2440.00 4880.00 7320.00 0.75 -0.60 0.23 -40.61 -51.00 9760.00 -57.25 2402.00 2480.00 2440.00 4880.00 7320.00 9761.00 For more info such as gerber files, additional App Notes and specific component info go to: www.johansontechnology.com/nordic Written by: Manuel Carmona BDM/RF Engineer 4 Test Name: Dev ice under test: Test engineer: Johanson Balun 2mm nRF8001 Ketil Aas-Johansen Figure 7: 5th harmonic Figure 8: LO Figure 9: LO/2 Figure 10: 2LO 5th harmonic Center Frequency [MHz] Lev el [dBm] LO LO/2 2LO 12200.00 2790.86 1395.43 5581.71 -76.58 -60.91 -62.75 -66.66 For more info such as gerber files, additional App Notes and specific component info go to: www.johansontechnology.com/nordic Written by: Manuel Carmona BDM/RF Engineer 5 Appendix A High Frequency Ceramic Solutions P/N 2450BM14A0002 2.45 GHz Impedance Matched Balun-Filter: Optimized for Nordic's Chipset nRF24L01, nRF24L01+, nRF24LE1, nRF24LU1, nRF24AP2, and nRF8001 Detail Specification: 6/13/2012 Page 1 of 2 General Specifications Part Num ber 2450BM14A0002 Frequency (MHz) 2400 - 2500 50 Ω Unbalanced Im pedance Differential Balanced Im pedance Insertion Loss 2.0 dB max. Return Loss 9.5 dB min. Phase Difference Attenuation: Differential Mode 15 min.@4800~5000MHz 15 min.@7200~7500MHz Attenuation: Com m on Mode 20 min.@4800~5000MHz 160° ± 15° Am plitude Difference Imp. Co njugate match to No rdic nRF24L01, nRF24L01+, nRF24LE1, nRF24LU1, nRF24AP 2, and nRF8001 3.5 ± 1.5 dB Reel Quanity 4,000 Operating Tem perature -40 to +85°C Recom mended Storage Conditions +5 to +35°C, Humidity: 4575%RH, 18 mos. Max Term inal Configuration Part Number Explanation Packaging Style* P/N Suffix Termination Style No. Bulk Suffix = S T&R 100% Tin Tin / Lead Please consult Factory Function Eg. 2450BM14A0002S 1 Suffix = T Eg. 2450BM14A0002T 2 GND Suffix = None Eg. 2450BM14A0002(T or S) 3 Balanced Port F o r mo r e p akag i ng i nf o g o t o : ht t p :/ / w ww . jo hanso nt echno lo g y. co m/ i p cp ackag ing .ht ml Mechanical Dimensions In mm L 0.063 ± 0.004 1.60 ± 0.10 W 0.031 ± 0.004 0.80 ± 0.10 T 0.024 ± 0.004 0.60 ± 0.10 a 0.008 ± 0.004 0.20 ± 0.10 b 0.008 +.004/-.006 0.20 +0.1/-0.15 c 0.006 ± 0.004 0.15 ± 0.10 g 0.012 ± 0.004 0.30 ± 0.10 p 0.020 ± 0.002 0.50 ± 0.05 W Unbalanced Port 4 Balanced Port 5 DC Feed+RF GND or GND 6 NC 3 2 1 4 5 6 c L a p T g b Mounting Considerations Mount these devices w ith maroon mark facing up. 0.25 * Line w idth should be designed to provide 50 Ω impedance matching characteristics. * 0.3 Solder Resist Land Nordic Chipset Through-hole ( f 0.35) 0.55 Units: mm **Use this cap when utilizing with DC Feed 2.2nF Capacitor** 0.25 Johanson Technology, Inc. reserves the right to make design changes w ithout notice. All sales are subject to Johanson Technology, Inc. terms and conditions. www.johansontechnology.com 4001Calle Tecate • Camarillo, CA 93012 • TEL 805.389.1166 FA X 805.389.1821 2012 Jo hanso n Techno lo gy, Inc. A ll Rights Reserved For more info such as gerber files, additional App Notes and specific component info go to: www.johansontechnology.com/nordic Written by: Manuel Carmona BDM/RF Engineer 6 High Frequency Ceramic Solutions 2.45 GHz Impedance Matched Balun-Filter: Optimized for Nordic's Chipset nRF24L01, nRF24L01+, nRF24LE1, nRF24LU1, nRF24AP2, and nRF8001 P/N 2450BM14A0002 Detail Specification: 6/13/2012 Page 2 of 2 Typical RF Electrical Performance (T=25°C) 0 Att_CM_dB RL_dB IL_dB -10 -20 -30 -40 -50 1 2 3 4 5 6 7 8 freq, GHz For reference design notes and additional technical info please visit our Nordic Semiconductor dedicated page at: http://johansontechnology.com/nordic Johanson Technology, Inc. reserves the right to make design changes w ithout notice. All sales are subject to Johanson Technology, Inc. terms and conditions. www.johansontechnology.com 4001Calle Tecate • Camarillo , CA 93012 • TEL 805.389.1166 FA X 805.389.1821 2012 Jo hanso n Techno lo gy, Inc. A ll Rights Reserved The latest specification can be downloaded at: http://johansontechnology.com/nordic For more info such as gerber files, additional App Notes and specific component info go to: www.johansontechnology.com/nordic Written by: Manuel Carmona BDM/RF Engineer 7