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APPLICATION NOTE nRF9E5 RF and antenna layout 1. nAN900-05 General Gerber files for RF layouts have been made for Nordic Semiconductor’s nRF9E5 433/868/915 MHz RF Transceiver with Embedded 8051 Compatible Microcontroller and 4 Input, 10 Bit ADC [1]. The RF layouts include the external EEPROM needed for the nRF9E5 program code. A loop antenna for 433MHz has also been made available. The Gerber files for each layout are compressed into the Zip archive format. The Zip archive files includes a file named readme.wri that must be read before importing the Gerber files into the PCB editor. All described layouts should be fabricated on standard 1.6mm double-sided FR4 printed circuit board. 2. RF layout for nRF9E5 The RF layouts include all necessary circuitry to implement the nRF9E5 in a short-range communication system. All digital I/O signals and ADC inputs are available at the perimeter of the RF layout and should be connected to the peripheral part of a customer’s application. The serial EEPROM needed for the nRF9E5 program code is included on the layout. The EEPROM is of a standard 2XX320 SPI type, and the footprint used is SO-8. Supply voltage and GND are also available at the perimeter of the layout. The supply voltage for this part of the application circuit should be filtered separately from the supply voltages of any high current peripheral circuitry. Star routing is strictly recommended from the voltage supply source to the different parts of the application circuitry. All RF layouts presented below are equal except for the antenna connection circuitry. Solutions for differential connection to a differential antenna and single ended connection to a 50Ω antenna are presented. 2.1. Differential connection to a differential antenna Figure 1 shows the schematics for RF layout with differential connection to a differential antenna. The PCB layout is shown in Figure 2. The loop antenna layout described in chapter 3 can easily be placed together with this RF layout. The connection points numbered 1, 2 and 3 on the loop antenna layout must be connected exactly to the corresponding connection points numbered 1, 2 and 3 on the RF layout. The Gerber files Zip archive filename is PCB_nRF9E5_diff_0603_2-0.zip. The recommended external components are as given in Table 1 for all frequency bands. www.BDTIC.com/NORDIC Nordic Semiconductor ASA Revision: 2.1 - Vestre Rosten 81, N-7075 Tiller, Norway Page 1 of 13 - Phone +47 72 89 89 00 - Fax +47 72 89 89 89 June 2006 APPLICATION NOTE nRF9E5 RF and antenna layout aaaaaaaa R3 AREF 1K AIN3 AIN2 AIN1 AIN0 C9 1nF C10 100nF C5 33pF C6 4.7nF VDD C7 10nF 32 31 30 29 28 27 26 25 VDD P01 P02 P03 VDD VSS P04 P05 P06 VSS IR EF VSS ANT2 ANT1 VDD_PA VSS VDD nRF9E5 24 23 22 21 20 19 18 17 33pF, ±5% 433MHz 180pF, ±5% Loop antenna connection C3 1 3 2 VDD P07 MOSI MISO SCK EECSN XC1 XC2 VSS VDD P00 DVDD_1V2 AREF AIN0 AIN1 AIN2 AIN3 VDD 1 2 3 4 5 6 7 8 C3 U1 nRF9E5 R4 47K 9 10 11 12 13 14 15 16 aaaaaaaa P00 P01 P02 P03 P04 P05 P06 P07 MOSI (P1.1) MISO (P1.2) SCK (P1.0) EECSN (P1.3) 868/915MHz R2 22K aaaaaaaa R5 47K C8 33pF VDD U2 1 2 3 4 R6 100K CS SO WP VSS 8 7 6 5 VCC HOLD SCK SI C4 3.3nF X1 C11 10nF 25XX320 16 MHz R1 1M C1 22pF C2 22pF aaaaaaaa Figure 1. nRF9E5 schematics for RF layout with differential connection to a differential antenna No components in bottom layer a) Top silk screen b) Bottom silk screen c) Top view d) Bottom view Figure 2. nRF9E5 RF layout with differential connection to a differential antenna, all frequency bands www.BDTIC.com/NORDIC Nordic Semiconductor ASA Revision: 2.1 - Vestre Rosten 81, N-7075 Tiller, Norway Page 2 of 13 - Phone +47 72 89 89 00 - Fax +47 72 89 89 89 June 2006 APPLICATION NOTE nRF9E5 RF and antenna layout Component Description Size Value Tolerance Units C1 C2 C3 Capacitor ceramic, 50V, NP0, (Crystal oscillator) Capacitor ceramic, 50V, NP0, (Crystal oscillator) Capacitor ceramic, 50V, NP0, (PA supply decoupling) @ 433MHz @ 868/915MHz Capacitor ceramic, 50V, X7R, (PA supply decoupling) Capacitor ceramic, 50V, NP0, (Supply decoupling) Capacitor ceramic, 50V, X7R, (Supply decoupling) Capacitor ceramic, 50V, X7R, (Supply decoupling) Capacitor ceramic, 50V, NP0, (Supply decoupling) Capacitor ceramic, 50V, X7R, (AREF filtering) Capacitor ceramic, 50V, X7R, (AREF filtering) Capacitor ceramic, 50V, X7R Resistor. 0.1W, (Crystal oscillator bias) Resistor. 0.1W, (Reference bias) Resistor. 0.1W Resistor, 0.1W, (MISO pull-down) Resistor, 0.1W, (EECSN pull-up) Resistor, 0.1W nRF9E5 RF Transceiver 4 kbyte serial EEPROM with SPI interface Crystal, CL = 12pF, ESR < 100Ω, C0 < 7.0pF 0603 0603 0603 22 22 ±5% ±5% ±5% pF pF pF ±10% ±5% ±10% ±10% ±5% ±10% ±10% ±10% ±5% ±1% ±10% ±10% ±10% ±10% nF pF nF nF pF nF nF nF MΩ kΩ kΩ kΩ kΩ kΩ < +/- 30 ppm (frequency tolerance at 25°C + temperature drift) MHz C4 C5 C6 C7 C8 C9 C10 C11 R1 R2 R3 R4 R5 R6 U1 U2 X1 0603 0603 0603 0603 0603 0603 0603 0603 0603 0603 0603 0603 0603 0603 QFN32L/5x5 SO8 LxWxH = 4.0x2.5x0.8mm 180pF 33pF 3.3 33 4.7 10 33 1 100 10 1 22 1 47 47 100 2XX320 16 1) Table 1. nRF9E5 recommended external components for all frequency bands 1) nRF9E5 can operate at several crystal frequencies, please refer to [1]. www.BDTIC.com/NORDIC Nordic Semiconductor ASA Revision: 2.1 - Vestre Rosten 81, N-7075 Tiller, Norway Page 3 of 13 - Phone +47 72 89 89 00 - Fax +47 72 89 89 89 June 2006 APPLICATION NOTE nRF9E5 RF and antenna layout 2.2. Single ended connection to 50Ω Ω antenna by using a differential to single ended matching network Figure 3 shows the schematics for nRF9E5 with single ended connection to 50Ω antenna by using a differential to single ended matching network when operating at 433MHz. The PCB layout is shown in Figure 4. Figure 5 shows the schematics for nRF9E5 with single ended connection to 50Ω antenna by using a differential to single ended matching network when operating at 868/915MHz. The PCB layout is shown in Figure 6. The antenna connection point should be as close as possible to the output of the matching network. If this is not possible of practical reasons, the PCB track between the output of the matching network and the antenna connection should be carried out as a 50Ω microstrip line. In such a case, the length of the microstrip line is limited to a few centimeters. For a standard FR4 printed circuit board with 1.54mm substrate thickness and relative dielectric constant εr ≈ 4.45-4.25 at 433MHz-915MHz, the width of the microstrip line should be 3mm. For 433MHz operating nRF9E5, the Gerber files Zip archive filename is PCB_nRF905_single_netw_0603_433_2-0.zip. For 868/915MHz operating nRF905, the Gerber files Zip archive filename is PCB_nRF905_single_netw_0603_868-915_2-0.zip. The recommended external components are as given in Table 1, with addition of the components in the differential to single ended matching network as given in Table 2. www.BDTIC.com/NORDIC Nordic Semiconductor ASA Revision: 2.1 - Vestre Rosten 81, N-7075 Tiller, Norway Page 4 of 13 - Phone +47 72 89 89 00 - Fax +47 72 89 89 89 June 2006 APPLICATION NOTE nRF9E5 RF and antenna layout Component Description Size C12 Capacitor ceramic, 50V, NP0, (Impedance matching) @ 433MHz @ 868/915MHz Capacitor ceramic, 50V, NP0, (Impedance matching) @ 433MHz @ 868/915MHz Capacitor ceramic, 50V, NP0, (Impedance matching) @ 433MHz @ 868/915MHz Capacitor ceramic, 50V, NP0, (Impedance matching) @ 433MHz @ 868/915MHz Capacitor ceramic, 50V, NP0, (Impedance matching) @ 433MHz @ 868/915MHz Chip inductor, (Impedance matching) @ 433MHz: SRF>433MHz @ 868/915MHz: SRF>915MHz Chip inductor, (Impedance matching) @ 433MHz: SRF>433MHz @ 868/915MHz: SRF>915MHz Chip inductor, (Impedance matching) @ 433MHz: SRF>433MHz @ 868/915MHz: SRF>915MHz 0603 C13 C14 C15 C16 L1 L2 L3 Value Tolerance Units 3) pF ±5% <±0.25pF 18 5.6 3) 0603 pF 18 5.6 ±5% <±0.25pF optional 4) Not used ±0.25% 6.8 22 ±5% ±5% 0603 0603 pF pF 3) 0603 optional 4.7 5) ±5% <±0.25pF pF 3) nH 0603 12 12 ±5% ±5% 39 10 ±5% ±5% 3) 0603 nH 3) 0603 39 12 nH ±5% ±5% Table 2. nRF9E5 recommended components in the differential to single ended matching network, all frequency bands 3) To achieve more reproducible values of matching network insertion loss in mass production and hence less variation in output power and sensitivity, components with tighter tolerances can be utilized. 4) This capacitor is optional for 433MHz operating nRF9E5 and may be needed to tune the resonance frequency of the matching network if a printed circuit board which is different from a 1.6mm, 2 layer, FR4 printed circuit board is used. 5) This capacitor is optional for 433MHz operating nRF9E5 and may be needed in some designs to reduce harmonic emissions when measuring directly at the matching network output. www.BDTIC.com/NORDIC Nordic Semiconductor ASA Revision: 2.1 - Vestre Rosten 81, N-7075 Tiller, Norway Page 5 of 13 - Phone +47 72 89 89 00 - Fax +47 72 89 89 89 June 2006 APPLICATION NOTE nRF9E5 RF and antenna layout aaaaaaaa R3 AREF 1K AIN3 AIN2 AIN1 AIN0 C9 1nF C10 100nF C5 33pF C6 4.7nF VDD C7 10nF VDD 32 31 30 29 28 27 26 25 VDD P01 P02 P03 VDD VSS P04 P05 P06 U1 nRF9E5 R4 47K C15 L2 VSS IREF VSS ANT2 ANT1 VDD_PA VSS VDD nRF9E5 C12 18pF R2 22K P00 DVDD_1V2 AREF AIN0 AIN1 AIN2 AIN3 VDD 1 2 3 4 5 6 7 8 24 23 22 21 20 19 18 17 P07 MOSI MISO SCK EECSN XC1 XC2 VSS P00 P01 P02 P03 P04 P05 P06 P07 MOSI (P1.1) MISO (P1.2) SCK (P1.0) EECSN (P1.3) C16 Optional 50 ohm RF I/O 39nH 6.8pF C14 Optional L1 12nH C3 L3 VDD 39nH 180pF C13 18pF 9 10 11 12 13 14 15 16 aaaaaaaa R5 47K C8 33pF VDD U2 1 2 3 4 R6 100K CS SO WP VSS VCC HOLD SCK SI 8 7 6 5 C4 3.3nF X1 C11 10nF 25XX320 16 MHz R1 1M C1 22pF C2 22pF Figure 3. 433MHz operating nRF9E5 schematic, single ended connection to 50Ω antenna by using a differential to single ended matching network No components in bottom layer a) Top silk screen b) Bottom silk screen c) Top view d) Bottom view Figure 4. nRF9E5 RF layout for 433MHz operation, single ended connection to 50Ω antenna by using a differential to single ended matching network, all frequency bands www.BDTIC.com/NORDIC Nordic Semiconductor ASA Revision: 2.1 - Vestre Rosten 81, N-7075 Tiller, Norway Page 6 of 13 - Phone +47 72 89 89 00 - Fax +47 72 89 89 89 June 2006 APPLICATION NOTE nRF9E5 RF and antenna layout aaaaaaaa R3 AREF 1K C9 1nF AIN3 AIN2 AIN1 AIN0 C10 100nF VDD C7 10nF C5 33pF C6 4.7nF VDD P01 P02 P03 VDD VSS P04 P05 P06 U1 NRF9E5 VDD R4 47K nRF9E5 C12 5.6pF R2 22K VSS IREF VSS ANT2 ANT1 VDD_PA VSS VDD 24 23 22 21 20 19 18 17 P07 MOSI MISO SCK EECSN XC1 XC2 VSS 1 2 3 4 5 6 7 8 C15 C16 4.7pF L2 50 ohm RF I/O 10nH 22pF L1 12nH L3 VDD 12nH C3 33pF C13 5.6pF 9 10 11 12 13 14 15 16 aaaaaaaa R5 47K P00 P01 P02 P03 P04 P05 P06 P07 MOSI (P1.1) MISO (P1.2) SCK (P1.0) EECSN (P1.3) P00 DVDD_1V2 AREF AIN0 AIN1 AIN2 AIN3 VDD 32 31 30 29 28 27 26 25 VDD C8 33pF U2 1 2 3 4 R6 100K CS SO WP VSS VCC HOLD SCK SI 8 7 6 5 C4 3.3nF X1 C11 10nF 25XX320 16 MHz R1 C1 22pF 1M C2 22pF Figure 5. 868/915MHz operating nRF9E5 schematic, single ended connection to 50Ω antenna by using a differential to single ended matching network No components in bottom layer a) Top silk screen b) Bottom silk screen c) Top view d) Bottom view Figure 6. nRF9E5 RF layout for 868/915MHz operation, single ended connection to 50Ω antenna by using a differential to single ended matching network, all frequency bands www.BDTIC.com/NORDIC Nordic Semiconductor ASA Revision: 2.1 - Vestre Rosten 81, N-7075 Tiller, Norway Page 7 of 13 - Phone +47 72 89 89 00 - Fax +47 72 89 89 89 June 2006 APPLICATION NOTE nRF9E5 RF and antenna layout 3. Loop antenna layouts A loop antenna with T-match [2] is a good solution for low cost and small size radio modules. A layout solution for a small rectangular loop antenna for 433MHz operation is described below. Figure 7 shows the basic geometry of the designed rectangular loop antenna. a1 C1 C2 C3 a2 d/2 d/2 3 1 2 C4 C5 Figure 7. Geometry of rectangular loop antenna The loop antenna physical parameters are a1 a2 d b = loop antenna length [mm] = loop antenna width [mm] = feed length [mm] = width of loop conductor The antenna is tuned to a resonance frequency of 433MHz with chip capacitors C1, C2 and C3. Capacitors C1, C2 and C3 should be NP0 type and have tolerances equal to or better than ±0.1pF. Capacitors C4 and C5 should also be NP0 type and have tolerances equal to or better than ±5%. The loop antenna is tuned to approximately 300Ω with a T-match. The width of the loop conductor is 1mm (40mil). There is no ground plane beneath the antenna. Table 3 shows a summary of the designed loop antenna for 433MHz. Loop antenna a1 x a2 [mm] Feed length d [mm] Value [pF] 35x20 22.5 3.9 C1 Tolerance [pF] ±0.1 Value [pF] C2 Tolerance [pF] 6.8 ±0.1 Value [pF] 4.7 C3 Tolerance [pF] ±0.1 C4, C5 [pF] Zo [Ω Ω] 27 300 Table 3. Summary of the loop antenna for 433MHz operation The component values given in Table 3 are only valid when the connection points numbered 1, 2 and 3 on the loop antenna layout, as shown in Figure 8, are connected exactly to the www.BDTIC.com/NORDIC Nordic Semiconductor ASA Revision: 2.1 - Vestre Rosten 81, N-7075 Tiller, Norway Page 8 of 13 - Phone +47 72 89 89 00 - Fax +47 72 89 89 89 June 2006 APPLICATION NOTE nRF9E5 RF and antenna layout corresponding connection points numbered 1, 2 and 3 on the RF layout with differential connection. The component footprints used in the loop antenna layout are size 0603. The layout of the rest of the communication system may influence the antenna tuning and require measurement of the antenna together with the complete system in order to find the values for C1, C2 and C3 for your system. Figure 8. Loop antenna PCB layout It is recommended that a system should not be designed with a longer communication range than the application requires. Estimations on communication range with the antenna presented in this application note and a receiver with a given sensitivity and antenna gain, can be made based on the theory given in [2]. Initial communication range tests should be carried out with the lowest RF output power setting that, based on the estimations, satisfies the range requirements. If the achieved communication range does not satisfy the requirements, the RF output power should be increased to the required level. The Gerber files Zip archive filename for the antenna layout is Loop_35x20mm_433MHz_nRF9x5.zip. Measured gain of this 35x20mm loop antenna is approximately –18dBi. www.BDTIC.com/NORDIC Nordic Semiconductor ASA Revision: 2.1 - Vestre Rosten 81, N-7075 Tiller, Norway Page 9 of 13 - Phone +47 72 89 89 00 - Fax +47 72 89 89 89 June 2006 APPLICATION NOTE nRF9E5 RF and antenna layout 4. References 1. Product Specification nRF9E5, “433/868/915 MHz RF Transceiver with Embedded 8051 Compatible Microcontroller and 4 Input, 10 Bit ADC”, Nordic Semiconductor ASA. 2. Application note nAN400-03, “Small loop antennas”, Nordic Semiconductor ASA. www.BDTIC.com/NORDIC Nordic Semiconductor ASA Revision: 2.1 - Vestre Rosten 81, N-7075 Tiller, Norway Page 10 of 13 - Phone +47 72 89 89 00 - Fax +47 72 89 89 89 June 2006 APPLICATION NOTE nRF9E5 RF and antenna layout LIABILITY DISCLAIMER Nordic Semiconductor ASA reserves the right to make changes without further notice to the product to improve reliability, function or design. Nordic Semiconductor does not assume any liability arising out of the application or use of any product or circuits described herein. LIFE SUPPORT APPLICATIONS These products are not designed for use in life support appliances, devices, or systems where malfunction of these products can reasonably be expected to result in personal injury. Nordic Semiconductor ASA customers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify Nordic Semiconductor ASA for any damages resulting from such improper use or sale. Application Note, Revision: 2.1, Date: 23.06.2006. Application Note order code: 230606-nAN900-05 All rights reserved ®. Reproduction in whole or in part is prohibited without the prior written permission of the copyright holder. www.BDTIC.com/NORDIC Nordic Semiconductor ASA Revision: 2.1 - Vestre Rosten 81, N-7075 Tiller, Norway Page 11 of 13 - Phone +47 72 89 89 00 - Fax +47 72 89 89 89 June 2006 APPLICATION NOTE nRF9E5 RF and antenna layout YOUR NOTES www.BDTIC.com/NORDIC Nordic Semiconductor ASA Revision: 2.1 - Vestre Rosten 81, N-7075 Tiller, Norway Page 12 of 13 - Phone +47 72 89 89 00 - Fax +47 72 89 89 89 June 2006 APPLICATION NOTE nRF9E5 RF and antenna layout Nordic Semiconductor - World Wide Distributors For Your nearest dealer, please see http://www.nordicsemi.no Main Office: Vestre Rosten 81, N-7075 Tiller, Norway Phone: +47 72 89 89 00, Fax: +47 72 89 89 89 Visit the Nordic Semiconductor ASA website at http://www.nordicsemi.no www.BDTIC.com/NORDIC Nordic Semiconductor ASA Revision: 2.1 - Vestre Rosten 81, N-7075 Tiller, Norway Page 13 of 13 - Phone +47 72 89 89 00 - Fax +47 72 89 89 89 June 2006
