AN11338 BGU8011 GNSS front end evaluation board Rev. 1 — 29 May 2013 Application note Document information Info Content Keywords BGU8011, GNSS, FE, LNA Abstract This document explains the BGU8011 GNSS FE evaluation board Ordering info Board-number: OM7842 12NC: 9340 679 11598 Contact information For more information, please visit: http://www.nxp.com AN11338 NXP Semiconductors BGU8011 GNSS FE EVB Revision history Rev Date Description 1 First publication 20130529 Contact information For more information, please visit: http://www.nxp.com For sales office addresses, please send an email to: [email protected] AN11338 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 29 May 2013 © NXP B.V. 2013. All rights reserved. 2 of 26 AN11338 NXP Semiconductors BGU8011 GNSS FE EVB 1. Introduction NXP Semiconductors’ BGU8011 Global Navigation Satellite System (GNSS) Front end Evaluation Board (BGU8011 GNSS FE EVB) is designed to evaluate the performance of the GNSS front end using: NXP Semiconductors’ BGU8011 GNSS Low Noise Amplifier A matching inductor A decoupling capacitor Two identical GNSS band-pass filters NXP Semiconductors’ BGU8011 is a low noise amplifier for GNSS receiver applications 3 in a plastic, leadless 6 pin, extremely thin small outline SOT1230 at 1.1 x 0.9 x 0.5mm , 0.4mm pitch. The BGU8011 features gain of 16.3 dB and a noise figure of 0.65 dB at a current consumption of 4.4 mA. Its superior linearity performance removes interference and noise from co-habitation cellular transmitters, while retaining sensitivity. The LNA 2 components occupy a total area of approximately 8.4 mm . In this document, the application diagram, board layout, bill of materials, and typical results are given, as well as some explanations on GNSS related performance parameters like out-of-band input third-order intercept point O_IIP3, gain compression under jamming and noise under jamming. Fig 1. AN11338 Application note BGU8011 GNSS front end evaluation board All information provided in this document is subject to legal disclaimers. Rev. 1 — 29 May 2013 © NXP B.V. 2013. All rights reserved. 3 of 26 AN11338 NXP Semiconductors BGU8011 GNSS FE EVB 2. General description Modern smart phones have multiple radio systems, so problems like co-habitation are quite common. A GNSS receiver implemented in a mobile phone requires the following factors to be taken into account. All the different transmit signals that are active in smart phones and tablets can cause problems like intermodulation and compression. Since the GNSS receiver needs to receive signals with an average power level of -130 dBm, sensitivity is very important. Many of the available GNSS ICs have integrated LNA front ends. The noise performance of these integrated LNA front ends, and as a result the system sensitivity, is not always adequate. The GNSS receiver sensitivity is a measure for how accurate the coordinates are calculated. The GNSS signal reception can be improved by a so called GNSS front end, which improves the sensitivity by filtering out the unwanted jamming signals and by amplifying the wanted GNSS signal with a low noise amplifier. The pre-filters and post filters are needed to improve the overall linearity of the system as well as to avoid overdriving the integrated LNA stage of the GNSS receiver. AN11338 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 29 May 2013 © NXP B.V. 2013. All rights reserved. 4 of 26 AN11338 NXP Semiconductors BGU8011 GNSS FE EVB 3. BGU8011 GNSS front end evaluation board The BGU8011 front end evaluation board simplifies the RF evaluation of the BGU8011 GNSS LNA applied in a GNSS front end, that is often used in smart phones. The evaluation board enables testing of the device RF performance and requires no additional support circuitry. The board is fully assembled with the BGU8011, including the input series inductor, decoupling capacitor as well as two SAW filters to optimize the linearity performance. The board is supplied with two SMA connectors for input and output connection to RF test equipment. The BGU8011 can operate from a 1.5 V to 3.1 V single supply and consumes about 4.4 mA. 3.1 Application Circuit The circuit diagram of the evaluation board is shown in Fig 2. With jumper JU1 the enable input can be connected either to Vcc or GND. BGU8011 GNSS FE EVB X3 GND Ven Vcc X4 JU1 C1 6 2 RF in L1 5 BGU8011 SAW 4 X1 RF out 3 SAW X2 1 Fig 2. Circuit diagram of the BGU8011 front end evaluation board 3.2 PCB Layout A good PCB layout is an essential part of an RF circuit design. The front end evaluation board of the BGU8011 can serve as a guideline for laying out a board using the BGU8011. Use controlled impedance lines for all high frequency inputs and outputs. Bypass Vcc with decoupling capacitors, preferably located as close as possible to the AN11338 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 29 May 2013 © NXP B.V. 2013. All rights reserved. 5 of 26 AN11338 NXP Semiconductors BGU8011 GNSS FE EVB device. For long bias lines it may be necessary to add decoupling capacitors along the line further away from the device. Proper grounding of the GND pins is also essential for good RF performance. Either connect the GND pins directly to the ground plane or through vias, or do both, which is recommended. The out-of-band rejection of the SAW filters also depends on the grounding of the filter. The material that has been used for the evaluation board is FR4 using the stack shown in Fig 4. The input circuit has also SMDpositions for optional input filtering circuits (not used in this version of the FE EVB). 3.3 Board Layout Fig 3. AN11338 Application note Printed-Circuit Board layout of the BGU8011 front end evaluation board All information provided in this document is subject to legal disclaimers. Rev. 1 — 29 May 2013 © NXP B.V. 2013. All rights reserved. 6 of 26 AN11338 NXP Semiconductors BGU8011 GNSS FE EVB 20um Cu 0.2mm FR4 Critical 20um Cu 0.8mm FR4 only for mechanical rigidity of PCB 20um Cu (1) Material supplier is ISOLA DURAVER; εr = 4.6-4.9: T Fig 4. Stack of the PCB material 4. Bill of materials Table 1. BOM of the BGU8011 GNSS front end evaluation board Designator Description Footprint Value Supplier Name/type Marking code: C BGU8011 1.1 x 0.9 x 0.5 3 mm NXP Comment SOT1230 0.4 mm pitch PCB 20 x 35 mm 2 BGU8011 GNSS FE EV Kit C1 Capacitor 0402 1nF Murata GRM1555 Decoupling L1 Inductor 0402 5.6nH Murata LQW15 Input matching JK SAW BPF 1.4 x 1.1 x 0.4 EPCOS B8313 [1] Johnson, End launch SMA RF input/ RF output mm 3 X1, X2 SMA RF connector - - X3 DC header - - Molex, PCB header, Right Angle, 1 row, 3 way 90121-0763 Bias connector X4 JUMPER - - Molex, PCB header, Vertical, 1 row, 3 way 90120-0763 Connect Ven to Vcc or separate Ven voltage Stage JU1 [1] 142-0701-841 JUMPER Similar performance can also be achieved with GNSS SAW filters from other suppliers. See paragraph 4.2 AN11338 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 29 May 2013 © NXP B.V. 2013. All rights reserved. 7 of 26 AN11338 NXP Semiconductors BGU8011 GNSS FE EVB 4.1 BGU8011 By dynamically suppressing strong cellular and WLAN transmit signals, an industry first, these LNAs offer the best reception of weak GPS signals. Linearity improves with a 10 dB better IP3 under -40 to -20 dBm jamming conditions, while NF remains below 1 dB. Requiring only two external components, they save up to 50% in PCB size and 10% in component cost, offering the smallest footprint in the market. The BGU8011 is a Low Noise Amplifier (LNA) for GNSS receiver applications, available in a small plastic 6-pin extremely thin leadless package. The BGU8011 requires one external matching inductor and one external decoupling capacitor. The BGU8011 adapts itself to the changing environment resulting from co-habitation of different radio systems in modern cellular handsets. It has been designed for low power consumption and optimal performance when jamming signals from co-existing cellular transmitters are present. At low jamming power levels it delivers 16.3 dB gain at a noise figure of 0.65 dB. During high jamming power levels, resulting for example from a cellular transmit burst, it temporarily increases its bias current to improve sensitivity. 4.2 Band pass filters The band-pass filters that are implemented in the GNSS front end evaluation board are key components regarding the overall system linearity and sensitivity. One of the key performance indicators of these filters is having very high rejection at the different smart phone TX frequencies, and simultaneously having low insertion loss in the GNSS passband. The evaluation board is supplied with two EPCOS B8313 SAW-filters (GPS, COMPASS, Galileo and GLONASS). Alternatives to be considered: 1. Murata SAFA1G57KH0F00 2. Murata SAFA1G57KB0F00 low loss variant 3. Fujitsu FAR-F6KA-1G5754-L4AA 4. Fujitsu FAR-F6KA-1G5754-L4AJ All these filters can use the same footprint. In order to be able to achieve the rejection level as indicated in the data sheet of these filters, it is necessary that the filters are properly grounded. In the layout of the front end evaluation board the suppliers’ recommendations have been followed. See Fig 5, please note that every GND pin has its own ground-via and there is a ground path between the input and the output. AN11338 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 29 May 2013 © NXP B.V. 2013. All rights reserved. 8 of 26 AN11338 NXP Semiconductors BGU8011 GNSS FE EVB Fig 5. SAW filter footprint 4.3 Series inductor The evaluation board is supplied with Murata LQW15 series inductor of 5.6nH. This is a wire wound type of inductor with high quality factor (Q) and low series resistance (Rs). This type of inductor is recommended in order to achieve the best noise performance. High Q inductors from other suppliers can be used. If it is decided to use other low cost inductors with lower Q and higher Rs the noise performance will degrade. AN11338 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 29 May 2013 © NXP B.V. 2013. All rights reserved. 9 of 26 AN11338 NXP Semiconductors BGU8011 GNSS FE EVB 5. Required Equipment In order to measure the evaluation board the following is necessary: AN11338 Application note DC Power Supply up to 30 mA at 1.5 V to 3.1 V Two RF signal generators capable of generating RF signals at the operating frequency of 1575.42 MHz, as well as the jammer frequencies 1713.42 MHz and 1851.42 MHz An RF spectrum analyzer that covers at least the operating frequency of 1575.42 MHz as well as a few of the harmonics. Up to 6 GHz should be sufficient. “Optional” a version with the capability of measuring noise figure is convenient Amp meter to measure the supply current (optional) A network analyzer for measuring gain, return loss and reverse isolation Noise figure analyzer and noise source Directional coupler Proper RF cables All information provided in this document is subject to legal disclaimers. Rev. 1 — 29 May 2013 © NXP B.V. 2013. All rights reserved. 10 of 26 AN11338 NXP Semiconductors BGU8011 GNSS FE EVB 6. Connections and setup The BGU8011 GNSS front end evaluation board is fully assembled and tested. Please follow the steps below for a step-by-step guide to operate the front end evaluation board and test the device functions. 1. Connect the DC power supply to the Vcc and GND terminals. Set the power supply to the desired supply voltage, between 1.5 V and 3.1 V, but never exceed 3.1 V as it might damage the BGU8011. 2. Jumper JU1 is connected between the Vcc terminal of the evaluation board and the Ven pin of the BGU8011. 3. Connect the RF signal generator and the spectrum analyzer to the RF input and the RF output of the evaluation board, respectively. Do not turn on the RF output of the signal generator yet, set it to -40 dBm output power at 1575.42 MHz, set the spectrum analyzer at 1575.42 MHz center frequency and a reference level of 0 dBm. 4. Turn on the DC power supply and it should read approximately 4.4mA. 5. Enable the RF output of the generator: The spectrum analyzer displays a tone around –25 dBm at 1575.42 MHz. 6. Instead of using a signal generator and spectrum analyzer one can also use a network analyzer in order to measure gain as well as in- and output return loss. 7. For noise figure evaluation, either a noise figure analyzer or a spectrum analyzer with noise option can be used. The use of a 15 dB noise source, like the Agilent 364B is recommended. When measuring the noise figure of the evaluation board, any kind of adaptors, cables etc between the noise source and the evaluation board should be avoided, since this affects the noise figure. Fig 6. AN11338 Application note Evaluation board including its connections All information provided in this document is subject to legal disclaimers. Rev. 1 — 29 May 2013 © NXP B.V. 2013. All rights reserved. 11 of 26 AN11338 NXP Semiconductors BGU8011 GNSS FE EVB 7. Linearity At the average power levels of –130 dBm that have to be received by a GNSS receiver, the system will not have in-band intermodulation problems caused by the GNSS-signal itself. Strong out-of-band smart phone TX jammers however can cause linearity problems, and result in third-order intermodulation products in the GNSS frequency band. In this chapter the effects of these Jammer-signals on the Noise and Gain performance of the BGU8011 are described. The effect of these Jammers on the In-band and Out-of-Band Third-Order Intercept points are described in more detail in a separate User Manual: UM10453: 2-Tone Test BGU7005 and BGU7007 GPS LNA. 7.1 Out-of-band input third-order intercept point This parameter is being measured by a two-tone measurement where the carriers have been chosen as L1+138 MHz and L1+276 MHz. Where L1 is the center of the GNSS band, 1575.42 MHz. So the two carriers are 1713.42 MHz and 1851.42 MHz that can be seen as two TX jammers in UMTS FDD and GSM1800 cell phone systems. One third-order product (2f1-f2) generated in the LNA due to amplifier third-order nonlinearities can fall at the desired 1575.42 MHz frequency as follows: 2f1-f2 = 2(1713.42 MHz)-1851.42 MHz = 1575.42 MHz. This third-order product can influence the sensitivity of the GNSS receiver drastically. So this third-order intermodulation product needs to be as low as possible, meaning the outof-band intercept point must be as high as possible. Fig 7 shows the measurement setup used to measure the out-of-band third order intercept point. Two RF-generators are used to generate the jammers f 1 and f2. These two jammers are combined by an RF combiner. A notch filter is used to prevent inserting an RF signal at the GNSS frequency into the front end caused by intermodulation of the two generators and RF combiner combination. BGU7007 BGU8011 GPS FE GNSS FE EVB EVB X3 X3 GND GND VVenen Vcc cc X4X4 JU1 JU1 RF-generator 2 RF-generator 1 Fig 7. RF combiner GPS notch C1C1 65 RF RFinin X1 SAW 2 L1L1 5 3 4 BGU7007 BGU8011 SAW X1 41 12 6 3 SAW RF RFout out SAW Spectrum analyzer X2 X2 Out-of-band input third order intercept point measurement setup AN11338 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 29 May 2013 © NXP B.V. 2013. All rights reserved. 12 of 26 AN11338 NXP Semiconductors BGU8011 GNSS FE EVB The input power levels of f1 and f2 that have been used to measure the IM3 levels on the front end evaluation board were +10 dBm, shown in Fig 8. Fig 9 shows the IM3 level at the output of the front end, measured at VCC = 2.85 V. With the levels shown in Fig 8 and Fig 9, the out-of-band input third-order intercept point can be calculated. As shown in Fig 8 Pin of both f1 and f2 is +10 dBm. Left-side OIM3 = -93.7 dBm (see Fig 9) The gain ( G p ) of the front end is 14.9 dB (the typ. insertion loss of the EPCOS B8313 SAW filters is ~0.8dB). Fig 8. Input jammers for IM3 measurements f1=1713MHz/+10dBm and f2=1851MHz/+10dBm AN11338 Application note Fig 9. FE output IM3 level at 1575 MHz All information provided in this document is subject to legal disclaimers. Rev. 1 — 29 May 2013 © NXP B.V. 2013. All rights reserved. 13 of 26 AN11338 NXP Semiconductors BGU8011 GNSS FE EVB 7.2 In-band 1dB gain compression due to 787MHz, 850MHz and 1850MHz jammers For the measurement described below it is necessary to have clean jammer signals with high RF power in order to measure these parameters on the actual front end evaluation board. Since these clean signals are hard to generate, these measurements are performed on a BGU8011 GNSS Low noise amplifier evaluation board (user manual available: AN11337). With the results of these measurements and the typical rejection levels of the band-pass filters at the jamming frequencies, the values valid for the front end evaluation board can be calculated. As already stated before, signal levels in the GNSS frequency band of -130dBm average will not cause linearity problems in the GNSS band itself. This of course is also valid for the 1dB gain compression in-band. The 1dB compression point at 1575.42MHz caused by smart phone TX jammers however is important. Measurements have been carried out using the setup shown in Fig 10. BGU7007 BGU8011 GPS LNA GNSS LNA EVB X3 X3 GND GND Ven en Vcc cc EVB X4 Jammer signal JU1 JU1 RF-generator 2 C1 65 RF-generator 1 -20dB RF RF in in Directional coupler 2 L1 L1 4 53 BGU7007 BGU8011 BGU8006 41 X1 X1 12 63 RF out out Spectrum analyzer X2 X2 Fig 10. 1dB Gain compression under jamming measurement setup (LNA evaluation board) The gain was measured between port RFin and RFout of the EVB at the GNSS frequency, while simultaneously a jammer power signal was swept at 20dB attenuated input of the directional coupler. Please note that the drive power of the jammer is 20dB lower at the input of the DUT caused by the directional coupler. Fig 11, Fig 12 and Fig 13 show the gain compression curves with 787MHz, 850MHz and 1850MHz jammers respectively (taking into account the approx 20 dB attenuation of the directional coupler and RF-cable from Jammer-Generator to the directional coupler). AN11338 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 29 May 2013 © NXP B.V. 2013. All rights reserved. 14 of 26 AN11338 NXP Semiconductors BGU8011 GNSS FE EVB Calculating the power level at the front end gain with 1 dB compression is done as follows: At 1 dB gain drop the jammer input power for 850MHz jammer is approx. at -6 dBm (Vcc = 2.85 V, Fig 11). This is for the LNA only. Using the typical rejection of the SAW filter at (1) 850 MHz which is 51dB the 1dB compression jammer signal level equals: -6 + 51 = +45 dBm. At 1 dB gain drop the jammer input power for 850MHz jammer is approx. at -6 dBm (Vcc = 2.85 V, Fig 12). This is for the LNA only. Using the typical rejection of the SAW filter at (2) 850 MHz which is 51dB the 1dB compression jammer signal level equals: -6 + 51 = +45 dBm. For 1850 MHz jammer the jammer input power is approx. at -3 dBm (Vcc = 2.85 V, Fig 13). Again this is for the LNA only. Using the typical rejection of the SAW filter at 1850 (3) MHz which is 43 dB the 1 dB compression jammer signal level equals: -3 + 43 = +40 dBm. Gain=f(P_Jammer) Gain=f(P_Jammer) BGU8011 LNA- & FE-EVB, F_Jammer=787Hz FE-EVB: Calculated values BGU8011 LNA- & FE-EVB, F_Jammer=850MHz FE-EVB: Calculated values 18 18 17 17 16 16 1.50V, LNA-EVB 1.50V, LNA-EVB 15 1.80V, LNA-EVB 2.85V, LNA-EVB 14 3.1V, LNA-EVB 1.50V, FE-EVB 13 Gain [dB] Gain [dB] 15 1.80V, LNA-EVB 2.85V, LNA-EVB 14 3.1V, LNA-EVB 1.50V, FE-EVB 13 1.80V, FE-EVB 12 2.85V, FE-EVB 3.1V, FE-EVB 11 10 1.80V, FE-EVB 12 2.85V, FE-EVB 3.1V, FE-EVB 11 10 -40 -30 -20 -10 0 10 20 30 40 50 -40 -30 -20 -10 P_Jammer [dBm] (Pin 1575 MHz = -45 dBm) AN11338 Application note 10 20 30 40 50 (Pin 1575 MHz = -45 dBm) Fig 11. Gain versus jammer power at 787 MHz 1. 2. 3. 0 P_Jammer [dBm] Fig 12. Gain versus jammer power at 850 MHz Typical rejection at 787MHz from datasheet of EPCOS B8313 SAW filter Typical rejection at 850MHz from datasheet of EPCOS B8313 SAW filter Typical rejection at 1850MHz from datasheet of EPCOS B8313 SAW filter All information provided in this document is subject to legal disclaimers. Rev. 1 — 29 May 2013 © NXP B.V. 2013. All rights reserved. 15 of 26 AN11338 NXP Semiconductors BGU8011 GNSS FE EVB Gain=f(P_Jammer) BGU8011 LNA- & FE-EVB, F_Jammer=1850MHz FE-EVB: Calculated values 18 17 16 1.50V, LNA-EVB Gain [dB] 15 1.80V, LNA-EVB 2.85V, LNA-EVB 14 3.1V, LNA-EVB 1.50V, FE-EVB 13 1.80V, FE-EVB 12 2.85V, FE-EVB 3.1V, FE-EVB 11 10 -40 -30 -20 -10 0 10 20 30 40 50 P_Jammer [dBm] (Pin 1575 MHz = -45 dBm) Fig 13. Gain versus jammer power at 1850 MHz AN11338 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 29 May 2013 © NXP B.V. 2013. All rights reserved. 16 of 26 AN11338 NXP Semiconductors BGU8011 GNSS FE EVB 8. Noise figure as function of jammer power at 850MHz and 1850MHz For the measurement described below it is necessary to have clean jammer signals with high RF power in order to measure these parameters on the actual front end evaluation board. Since these clean signals are hard to generate, these measurements are performed on a BGU8011 GNSS Low noise amplifier evaluation board (user manual available: AN11230). With the results of these measurements and the typical rejection levels of the band-pass filters at the jamming frequencies, the values valid for the front end evaluation board can be calculated. Noise figure under jamming conditions is a measure of how the LNA behaves when e.g. a GSM TX interfering signal is at the input of the GNSS antenna. To measure this behavior the setup shown in Fig 14 is used. The jammer signal is coupled via a directional coupler to the DUT: this is to avoid the jammer signal damaging the noise source. The GNSS BPF is needed to avoid driving the second stage LNA in saturation. BGU7007 BGU8011 GPS LNA GNSS LNA EVB X3X3 GND GND VenVen VccVcc EVB X4X4 Jammer signal JU1 JU1 RF-generator C1C1 56 Noise Source -20dB RF RF in in Directional coupler 2 L1 L1 4 35 BGU7007 BGU8011 14 X1 X1 6 3 RFRF outout SAW 2nd stage LNA Noise analyzer X2 21 X2 Fig 14. Noise under jamming measurement setup (LNA evaluation board) With the results of these measurements and the specification of the SAW filter, the jammer power levels that cause noise increase can be calculated. Calculating the power level at which the front end noise starts to increase is done as follows: As can be seen in Fig 15 with a 850 MHz jammer the LNA starts increasing the noise at Pjam = -25 dBm (Vcc = 2.85 V). For the front end the TX rejection of the first BPF needs (4) to be added. For the SAW filter used the rejection at 850 MHz is 51 dB . This means the noise of the front end will start increasing at an 850 MHz jammer level of Pjam = -25 + 51 = +26 dBm. For the 1850 MHz jammer the LNA noise starts to increase at Pjam = -30 dBm (Vcc = 2.85 (5) V, see Fig 16). The rejection of the SAW filter at 1850 MHz is 43 dB . This means the 4. 5. AN11338 Application note Rejection at 850MHz from datasheet of EPCOS B8313 SAW filter Rejection at 1850MHz from datasheet of EPCOS B8313 SAW filter All information provided in this document is subject to legal disclaimers. Rev. 1 — 29 May 2013 © NXP B.V. 2013. All rights reserved. 17 of 26 AN11338 NXP Semiconductors BGU8011 GNSS FE EVB noise of the front end will start increasing at an 1850 MHz jammer level of Pjam = -30 +43 = +13 dBm. NF [dB]=f(P_Jammer) NF [dB]=f(P_Jammer) BGU8011 LNA- & FE-EVB, Fjammer=850MHz BGU8011 LNA- & FE-EVB, Fjammer=1850MHz FE-EVB: Calculated values FE-EVB: Calculated values 3.00 3.00 1.5V, LNA-EVB 2.00 1.5V, LNA-Board 2.00 2.85V, LNA-EVB 3.1V, LNA-EVB 1.5V, FE-EVB 1.00 1.8V, LNA-Board NF [dB] NF [dB] 1.8V, LNA-EVB 2.85V, LNA-Board 3.1V, LNA-Board 1.5V, FE-Board 1.00 1.8V, FE-EVB 1.8V, FE-Board 2.85V, FE-EVB 2.85V, FE-Board 3.1V, FE-Board 3.1V, FE-EVB 0.00 0.00 -40 -30 -20 -10 0 -40 -30 -20 -10 10 20 30 40 50 Incl. the losses of the connectors and the PCB. Measured at Tanb = 25 oC. Fig 15. NF at 1575 MHz versus jammer power at 850 MHz AN11338 Application note 0 10 20 30 40 50 P_Jammer [dBm] P_Jammer [dBm] Incl. the losses of the connectors and the PCB. Measured at Tanb = 25 oC. Fig 16. NF at 1575 MHz versus jammer power at 1850 MHz All information provided in this document is subject to legal disclaimers. Rev. 1 — 29 May 2013 © NXP B.V. 2013. All rights reserved. 18 of 26 AN11338 NXP Semiconductors BGU8011 GNSS FE EVB 9. TX rejection levels When measuring the front end evaluation board the input level of the network analyzer has to be on -45 dBm to avoid activating the adaptive biasing. This low input level results in a very inaccurate measurement result of the TX rejection. Fig 17 and Fig 18 show the typical TX rejection levels measured more accurate due to segmented power calibration. Typical BGU8011 FE-Board, Vcc=2.85V 0 10 0 -10 S21 [dB] -20 CELL BAND REJECTION >90dB PCS BAND REJECTION >80dB -30 Return Loss [dB] 20 S21 S11 S22 -40 -50 -60 -5 -10 -15 -20 -70 -80 -25 -90 -100 5.00E+08 1.00E+09 1.50E+09 Freq [Hz] 2.00E+09 -30 2.50E+09 Fig 17. Typical S-parameter plot at Vcc = 2.85 V AN11338 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 29 May 2013 © NXP B.V. 2013. All rights reserved. 19 of 26 AN11338 NXP Semiconductors BGU8011 GNSS FE EVB BGU8011 FE-Board 40 10 20 5 0 S21 [dB] 0 -20 -40 -5 S11 -10 S22 -60 -15 -20 -80 -100 1.4E+09 S21 -25 1.5E+09 1.6E+09 Freq [Hz] 1.7E+09 -30 1.8E+09 Fig 18. Typical pass band response at Vcc = 2.85 V AN11338 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 29 May 2013 © NXP B.V. 2013. All rights reserved. 20 of 26 AN11338 NXP Semiconductors BGU8011 GNSS FE EVB 10. LTE rejection level The second harmonic of an LTE signal (788MHz) falls into the GNSS band (2x 788MHz = 1576MHz) and can be responsible for a reduction of the sensitivity of the GNSSsystem. To test the Second Harmonic (H2) –performance, a measurement has been done. The measurement setup is given in Fig 19. A notch is used to reduce the second harmonic caused by the input generator. A 10dB attenuator is used to get a good 50Ω impedance (some notch filters have an output impedance which is not 50Ω over a wide frequency range). BGU7007 BGU8011 GPS LNA GNSS FE EVB X3 X3 GND Ven en Vcc cc EVB X4 Jammer signal Suppress H2RF-generator 2 JU1 JU1 RF-generator C1 65 RF-NOTCH-20dB ATT Directional coupler 10dB @1576MHz RF-generator 1 2 RF RF in in X1 L1 4 L1 53 BGU7007 BGU8011 SAW 41 X1 RF out RF out 63 SAW Spectrum analyzer X2 X2 12 F = 788MHz Improve mismatch RF-Notch-filter Fig 19. LTE rejection measurement setup (LNA evaluation board) Table 2 shows an overview of the measured performance (as comparison also the P_H2 results of the BGU8011 LNA-EVB is given; source: AN11288, BGU8011 GNSS LNA evaluation board). Table 2. Measured performance of BGU8011 LNA- and FE EVB’s Vcc=2.85V, Icc ~4.7mA, Temp = 25 °C Parameter Symbol Pin=0dBm Pin=+5dBm Pin=+10dBm Unit P_H2 (input referred) -82 dBm [1] P_H2 -102 -92 Remarks [1] Fin = 788MHz, Fmeas = 1576MHz. AN11338 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 29 May 2013 © NXP B.V. 2013. All rights reserved. 21 of 26 AN11338 NXP Semiconductors BGU8011 GNSS FE EVB 11. Typical front end evaluation board results Table 3. Typical results measured on the evaluation boards Operating Frequency is f = 1575.42 MHz unless otherwise specified; Temp = 25 °C Parameter Symbol FE EVB FE EVB FE EVB FE EVB Unit Supply Voltage Remarks VCC 1.5 1.8 2.85 3.1 V Supply Current ICC 4.1 4.2 4.4 4.5 mA Noise Figure NF 1.6 1.6 1.5 1.5 dB Power Gain Gp 14.5 14.7 14.9 15.0 dB Input Return Loss RLin 11.8 12.3 12.8 12.9 dB Output Return Loss RLout 13.8 13.6 13.5 13.5 dB Reverse Isolation ISOrev 29.4 29.4 29.5 29.5 dB Input 1dB Gain Compression Pi1dB -9.6 -7.8 -5.2 -5.0 dBm Output 1dB Gain Compression Po1dB 3.8 5.8 8.8 9.0 dBm Input 1dB Gain Compression jammer level at 850MHz Pi1dB850MHz +40 dBm [4] Input 1dB Gain Compression jammer level at 1850MHz Pi1dB1850MHz +45 dBm [4] P_H2 (input referred) P_H2 -82 dBm [3][4] Cell band rejection at 850 MHz relative to 1575.42 MHz TX_rej850MHz >90 dBc [4] Cell band rejection at 1850 MHz relative to 1575.42 MHz TX_rej1850MHz >80 dBc [4] Output third order intermod. OIM3 -93.7 dBm [5] Power settling time Ton <2 <2 <2 <2 µs Toff <1 <1 <1 <1 µs [2] [2] The noise figure and gain figures are measured at the SMA connectors of the evaluation board. The losses of the connectors and the PCB of approximately 0.1dB are not subtracted. Measured at Tanb = 25 oC. [3] Fin = 788MHz, Pin = +10dBm, Fmeas = 1576MHz. [4] These parameters are mainly determined by the TX rejection levels of the used BPFs, in this case the EPCOS B8313 SAW filter, but the performance can also be achieved with the use of GNSS SAW filters from other suppliers that are on the market. See paragraph 4.2. [5] Out of band IM3-component (OIM3) at 1575MHz, jammers at f1=f+138MHz and f2=f+276MHz, where f=1575MHz. Pin(f1)=Pin(f2)=+10dBm AN11338 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 29 May 2013 © NXP B.V. 2013. All rights reserved. 22 of 26 AN11338 NXP Semiconductors BGU8011 GNSS FE EVB 12. Legal information 12.1 Definitions Draft — The document is a draft version only. The content is still under internal review and subject to formal approval, which may result in modifications or additions. NXP Semiconductors does not give any representations or warranties as to the accuracy or completeness of information included herein and shall have no liability for the consequences of use of such information. 12.2 Disclaimers Limited warranty and liability — Information in this document is believed to be accurate and reliable. However, NXP Semiconductors does not give any representations or warranties, expressed or implied, as to the accuracy or completeness of such information and shall have no liability for the consequences of use of such information. In no event shall NXP Semiconductors be liable for any indirect, incidental, punitive, special or consequential damages (including - without limitation lost profits, lost savings, business interruption, costs related to the removal or replacement of any products or rework charges) whether or not such damages are based on tort (including negligence), warranty, breach of contract or any other legal theory. Notwithstanding any damages that customer might incur for any reason whatsoever, NXP Semiconductors’ aggregate and cumulative liability towards customer for the products described herein shall be limited in accordance with the Terms and conditions of commercial sale of NXP Semiconductors. Right to make changes — NXP Semiconductors reserves the right to make changes to information published in this document, including without limitation specifications and product descriptions, at any time and without notice. This document supersedes and replaces all information supplied prior to the publication hereof. Suitability for use — NXP Semiconductors products are not designed, authorized or warranted to be suitable for use in life support, life-critical or safety-critical systems or equipment, nor in applications where failure or malfunction of an NXP Semiconductors product can reasonably be expected to result in personal injury, death or severe property or environmental damage. NXP Semiconductors accepts no liability for inclusion and/or use of NXP Semiconductors products in such equipment or applications and therefore such inclusion and/or use is at the customer’s own risk. Applications — Applications that are described herein for any of these products are for illustrative purposes only. NXP Semiconductors makes no representation or warranty that such applications will be suitable for the specified use without further testing or modification. Customers are responsible for the design and operation of their applications and products using NXP Semiconductors products, and NXP AN11338 Application note Semiconductors accepts no liability for any assistance with applications or customer product design. It is customer’s sole responsibility to determine whether the NXP Semiconductors product is suitable and fit for the customer’s applications and products planned, as well as for the planned application and use of customer’s third party customer(s). Customers should provide appropriate design and operating safeguards to minimize the risks associated with their applications and products. NXP Semiconductors does not accept any liability related to any default, damage, costs or problem which is based on any weakness or default in the customer’s applications or products, or the application or use by customer’s third party customer(s). Customer is responsible for doing all necessary testing for the customer’s applications and products using NXP Semiconductors products in order to avoid a default of the applications and the products or of the application or use by customer’s third party customer(s). NXP does not accept any liability in this respect. Export control — This document as well as the item(s) described herein may be subject to export control regulations. Export might require a prior authorization from competent authorities. Evaluation products — This product is provided on an “as is” and “with all faults” basis for evaluation purposes only. NXP Semiconductors, its affiliates and their suppliers expressly disclaim all warranties, whether express, implied or statutory, including but not limited to the implied warranties of noninfringement, merchantability and fitness for a particular purpose. The entire risk as to the quality, or arising out of the use or performance, of this product remains with customer. In no event shall NXP Semiconductors, its affiliates or their suppliers be liable to customer for any special, indirect, consequential, punitive or incidental damages (including without limitation damages for loss of business, business interruption, loss of use, loss of data or information, and the like) arising out the use of or inability to use the product, whether or not based on tort (including negligence), strict liability, breach of contract, breach of warranty or any other theory, even if advised of the possibility of such damages. Notwithstanding any damages that customer might incur for any reason whatsoever (including without limitation, all damages referenced above and all direct or general damages), the entire liability of NXP Semiconductors, its affiliates and their suppliers and customer’s exclusive remedy for all of the foregoing shall be limited to actual damages incurred by customer based on reasonable reliance up to the greater of the amount actually paid by customer for the product or five dollars (US$5.00). The foregoing limitations, exclusions and disclaimers shall apply to the maximum extent permitted by applicable law, even if any remedy fails of its essential purpose. 12.3 Trademarks Notice: All referenced brands, product names, service names and trademarks are property of their respective owners. All information provided in this document is subject to legal disclaimers. Rev. 1 — 29 May 2013 © NXP B.V. 2013. All rights reserved. 23 of 26 AN11338 NXP Semiconductors BGU8011 GNSS FE EVB 13. List of figures Fig 1. Fig 2. Fig 3. Fig 4. Fig 5. Fig 6. Fig 7. Fig 8. Fig 9. Fig 10. Fig 11. Fig 12. Fig 13. Fig 14. Fig 15. Fig 16. Fig 17. Fig 18. Fig 19. BGU8011 GNSS front end evaluation board..... 3 Circuit diagram of the BGU8011 front end evaluation board ............................................... 5 Printed-Circuit Board layout of the BGU8011 front end evaluation board ................................ 6 Stack of the PCB material ................................. 7 SAW filter footprint ............................................ 9 Evaluation board including its connections ..... 11 Out-of-band input third order intercept point measurement setup ........................................ 12 Input jammers for IM3 measurements ............ 13 FE output IM3 level at 1575 MHz .................... 13 1dB Gain compression under jamming measurement setup (LNA evaluation board)... 14 Gain versus jammer power at 787 MHz .......... 15 Gain versus jammer power at 850 MHz .......... 15 Gain versus jammer power at 1850 MHz ........ 16 Noise under jamming measurement setup (LNA evaluation board) ............................................ 17 NF at 1575 MHz versus jammer power at 850 MHz ................................................................ 18 NF at 1575 MHz versus jammer power at 1850 MHz ................................................................ 18 Typical S-parameter plot at Vcc = 2.85 V........ 19 Typical pass band response at Vcc = 2.85 V .. 20 LTE rejection measurement setup (LNA evaluation board) ............................................ 21 AN11338 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 29 May 2013 © NXP B.V. 2013. All rights reserved. 24 of 26 AN11338 NXP Semiconductors BGU8011 GNSS FE EVB 14. List of tables Table 1. Table 2. Table 3. BOM of the BGU8011 GNSS front end evaluation board ............................................... 7 Measured performance of BGU8011 LNA- and FE EVB’s......................................................... 21 Typical results measured on the evaluation boards ............................................................. 22 AN11338 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 29 May 2013 © NXP B.V. 2013. All rights reserved. 25 of 26 AN11338 NXP Semiconductors BGU8011 GNSS FE EVB 15. Contents 1. 2. 3. 3.1 3.2 3.3 4. 4.1 4.2 4.3 5. 6. 7. 7.1 7.2 8. 9. 10. 11. 12. 12.1 12.2 12.3 13. 14. 15. Introduction ......................................................... 3 General description ............................................. 4 BGU8011 GNSS front end evaluation board ..... 5 Application Circuit .............................................. 5 PCB Layout ........................................................ 5 Board Layout ...................................................... 6 Bill of materials.................................................... 7 BGU8011 ........................................................... 8 Band pass filters................................................. 8 Series inductor ................................................... 9 Required Equipment ......................................... 10 Connections and setup ..................................... 11 Linearity ............................................................. 12 Out-of-band input third-order intercept point .... 12 In-band 1dB gain compression due to 787MHz, 850MHz and 1850MHz jammers ...................... 14 Noise figure as function of jammer power at 850MHz and 1850MHz ....................................... 17 TX rejection levels ............................................. 19 LTE rejection level............................................. 21 Typical front end evaluation board results ..... 22 Legal information .............................................. 23 Definitions ........................................................ 23 Disclaimers....................................................... 23 Trademarks ...................................................... 23 List of figures..................................................... 24 List of tables ...................................................... 25 Contents ............................................................. 26 Please be aware that important notices concerning this document and the product(s) described herein, have been included in the section 'Legal information'. © NXP B.V. 2013. All rights reserved. For more information, visit: http://www.nxp.com For sales office addresses, please send an email to: [email protected] Date of release: 29 May 2013 Document identifier: AN11338