nRF8001 App Note - Johanson Technology

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