Johanson Technology Impedance Matched Balun Filter Integrated Passive for Nordic’s nRF24L01 and nRF24L01+ Chipsets November 2009 (Last update: 06/13/2012) 1. Introduction The nRF24L01/nRF24L01+ from Nordic Semiconductor is a 2.45GHz one chip, ultra low power transceiver. Johanson Technology’s, 2450BM14A0002 LPF-Balun was specifically designed for use with the nRF24L01/nRF24L01+ chipsets. This matched balun greatly simplifies the RF front-end by considerably reducing component count, system variability, implementation size area, and PCB sensitivity. Figure 1. Component picture. The 2450BM14A0002 is an SMD six-pin LTCC device with a small foot print of only 1.6 mm x 0.8 mm (EIA 0603). www.johnsontechnology.com 1 2. Description of the Reference Design Johanson Technology has developed a solution with a chip Balun-Harmonic filter integrated passive component that is especially matched for the nRF24L01/nRF24L01+ ICs, the 2450BM15A0002, shown in Figure 1. p/n: 2450BM14A0001 Figure 2. Integrated Reference Design The rightmost is the JTI matched balun 2450BM14A0002. Please refer to Appendix A for the datasheet of the balun filter component. For more updated information from the Johanson Technology web site at: http://johansontechnology.com/nordic www.johnsontechnology.com 2 The traditional reference design for RF balun has been the discrete solution shown in Figure 2. Figure 2. Discrete Reference Design www.johnsontechnology.com 3 3. Layout Figure 3. Layer 1 of the Reference Design Layout In the event that the reference design can not be copied, 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 a minimum and preferably the same length and width that are used in the reference design. If this routing is not symmetrical, 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 nRF24L01/nRF24L01+ and 2450BM14A0002. www.johnsontechnology.com 4 4. Measurement Results All results presented in this chapter are based on measurements performed with nRF24L01/nRF24L01+ and 2450BM14A0002 Reference Design board. All measurement results presented are the average of each batch tested from typical devices. Johanson’s 2450BM14A0002 Harmonic 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. Fundamental Fundamental Hi Fundamental Mid 2nd Harmonic 3rd Harmonic 4th Harmonic Figure 4. Active Measurement Results www.johnsontechnology.com 5 Carrier Sweep 2nd Harmonic Sweep 3rd Harmonic Sweep 4th Harmonic Sweep Figure 5. Sweep Measurement Results www.johnsontechnology.com 6 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 2450BM14A0002 Part Num ber 2400 - 2500 Frequency (MHz) 50 Ω Unbalanced Im pedance Differential Balanced Im pedance Insertion Loss 2.0 dB max. Return Loss 9.5 dB min. 160° ± 15° Phase Difference Imp. Co njugate match to No rdic nRF24L01, nRF24L01+, nRF24LE1, nRF24LU1, nRF24A P 2, and nRF8001 Attenuation: Differential Mode 15 min.@4800~5000MHz 15 min.@7200~7500MHz Attenuation: Com m on Mode 20 min.@4800~5000MHz 3.5 ± 1.5 dB Am plitude Difference 4,000 Reel Quanity Operating Tem perature -40 to +85°C Recom m ended Storage Conditions +5 to +35°C, Humidity: 4575%RH, 18 mos. Max Term inal Configuration Part Number Explanation No. Bulk Packaging Style* P/N Suffix Term ination Style Suffix = S Eg. 2450BM14A0002S 1 Function Unbalanced Port T&R Suffix = T Eg. 2450BM14A0002T 2 GND 100% Tin Suffix = None Eg. 2450BM14A0002(T or S) 3 Balanced Port Tin / Lead Please consult Factory 4 Balanced Port 5 DC Feed+RF GND or GND 6 NC F o r mo r e p akag i ng inf o g o t o : ht t p :/ / w w w .jo hanso nt echno lo g y.co m/ ip 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 c L a p T g b Mounting Considerations Mount these devices w ith maroon mark facing up. *Line w idth should be designed to provide 50 Ω 0.25 Solder Resist * impedance matching characteristics. 0.3 Land Nordic Chipset Through-hole ( 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 www.johnsontechnology.com 7 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 from the following link: http://johansontechnology.com/nordic www.johnsontechnology.com 8