UM10490 User manual for the BGU7004 GPS Front end evaluation
Contents
1. PCB C1 L1 JK X1 X2 X3 X4 JU1 Description Footprint Value Supplier Name type Comment BGU7004 1 45x1mm LNA MMIC v1 1 35x20mm BGU7004 GPS FE EV Kit release 01 09 Capacitor 0402 1nF Murata GRM1555 Decoupling Inductor 0402 5 6nH Murata LQW15A High Q low Rs Input matching SAW BPF 1 4x1 1mm Murata SAFEA1G57KE0F00 Note 1 SMA RF Johnson End launch SMA RF input RF connector 442 0701 841 output DC header Molex PCB header Right Angle 1 Bias connector row 3 way 90121 0763 JUMPER Molex PCB header Vertical 1 row Connect Ven to stage 3 way 90120 0763 Vcc or separate Ven voltage Jumper Note 1 Although in this case the Murata SAFEA1G57KEOFO00 BPF is used the performance as given in this document can also be achieved with the use of GPS SAW filters from other See paragraph 4 2 UM10490 NXP B V 2011 All rights reserved User manual Rev 1 0 14 June 2011 6 of 19 NXP Semiconductors U M1 0490 BGU7004 GPS FE EVB 4 1 BGU7004 NXP Semiconductors BGU7004 GPS low noise amplifier is designed for the GPS frequency band The integrated biasing circuit is temperature stabilized which keeps the current constant over temperature It also enables the superior linearity performance of the BGU7004 The BGU7004 is also supplied with an enable function that allows it to be controlled via a logic signal In disabled mode it only consumes less than1 pA The output of the BGU7004 is interna2. Noise under jamming measurement setup GPS 2M stage SAN LNA Za A Nose ja gt S analyzer 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 13 with a 850 MHz jammer the LNA starts increasing the noise at Piam 25 dBm For the front end we have to add the TX rejection of the first BPF For the filter used these values are 42 dB 850 MHz and 47dB 1850 MHz This means the noise of the front end will start increasing at an 850 MHz jammer level of Pjam 17 dBm For the 1850 MHz jammer the LNA noise starts to increase also at Pjam 25 dBm this means for a typical rejection at 1850 MHz of 47dBm for the used SAW the front end noise starts to increase at Pjam 22 dBm see Fig 14 NF vs Jammer Power at 850MHz NF vs Jammer Power at 1850MHz Jammer frequency is 850 MHz Jammer frequency is 1850 MHz Fig 13 NF at 1 575 GHz versus jammer power Fig 14 NF at 1 575 GHz versus jammer power Pjam dBm UM10490 NXP B V 2011 All rights reserved User manual Rev 1 0 14 June 2011 15 of 19 NXP Semiconductors UM10490 9 TX rejection levels BGU7004 GPS FE EVB When measuring the front end evaluation board the input level of the VNA has to be on 45
3. 1575 42 MHz as well as a few of the harmonics so up to 6 GHz should be sufficient v Optional a version with the capability of measuring noise figure is convenient v Amp meter to measure the supply current optional v A network analyzer for measuring gain return loss and reverse Isolation v Noise figure analyzer and noise source v Directional coupler v Proper RF cables UM10490 NXP B V 2011 All rights reserved User manual Rev 1 0 14 June 2011 9 of 19 NXP Semiconductors U M1 0490 BGU7004 GPS FE EVB 6 Connections and setup The BGU7004 GPS 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 testing the device functions 1 Connect the DC power supply to the Vec and GND terminals Set the power supply to the desired supply voltage between 1 5 V and 2 85 V but never exceed 3 1 V as it might damage the BGU7004 2 Jumper JU1 is connected between the Ve terminal of the evaluation board and the Ven pin of the BGU7004 3 To evaluate the power on settling time t and the power off settling time tog it is also possible to use a separate voltage on the Ven eventually this voltage can be supplied by a pulse generator In this case jumper JU1 should be removed The definition of ton is the time from 10 to 90 of the maximum signal level and for t p the time from 90 to 10 of the maximum signal
4. 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 11 3 Trademarks Notice All referenced brands product names service names and trademarks are property of their respective owners NXP B V 2011 All rights reserved User manual Rev 1 0 14 June 2011 18 of 19 NXP Sem
5. 1 10 of 19 NXP Semiconductors U M1 0490 7 Linearity BGU7004 GPS FE EVB re T A g EV Kit gort BGU7TOSS GPs unu w lomo ee Jems 22 p eeooos w G g Q o o v D oo oO Fig 6 Evaluation board including its connections UM10490 7 1 At the average power levels of 130 dBm that have to be received by a GPS receiver the system will not have in band intermodulation problems caused by the GPS signal itself Strong out of band cell phone TX jammers however can cause linearity problems and result in third order intermodulation products in the GPS frequency band 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 GPS 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 2f f generated in the LNA due to amplifier third order non linearities can fall at the desired 1575 42 MHz frequency as follows 2f f2 2 1713 42MHz 1851 42 MHz 1575 42 MHz This third order product can influence the sensitivity of the GPS receiver drastically So this third order intermodulation product needs to be as low as possible meaning the out of band intercept point must be as high as possible The input power levels of f4 and fz that hav
6. UM10490 User manual for the BGU7004 GPS Front end evaluation board Rev 1 0 14 June 2011 User manual Document information Info Content Keywords LNA FE GPS SAW BGU7004 Mobile Phones Co habitation Abstract This document explains the BGU7004 AEC Q100 qualified GPS front end evaluation board NXP Semiconductors U M1 0490 BGU7004 GPS FE EVB Revision history Rev Date Description 1 0 20110614 First release Contact information For additional information please visit http www nxp com For sales office addresses please send an email to salesaddresses nxp com UM10490 NXP B V 2011 All rights reserved User manual Rev 1 0 14 June 2011 2 of 19 NXP Semiconductors U M1 0490 BGU7004 GPS FE EVB 1 Introduction NXP Semiconductors BGU7004 AEC Q100 qualified Global Positioning System Front End Evaluation Board BGU7004 GPS FE EVB is designed to evaluate the performance of the GPS front end using e NXP Semiconductors BGU7004 AEC Q100 qualified GPS low noise amplifier e amatching inductor e adecoupling capacitor e two identical GPS band pass filters It has a gain of 14 6 dB and a noise figure of 1 8 dB at a current consumption of 4 8mA Its superior linearity performance removes interference and noise from co habitation cellular transmitters while retaining sensitivity The front end components occupy a total area of approximately 3 x 3 mm In this document the
7. application diagram board layout bill of materials and typical results are given as well as some explanations on GPS related performance parameters like out of band input third order intercept point O_IIP3 gain compression under jamming and noise under jamming h tet 9 version 1 1 j E fo foo Ho He oO 00 ay Mite GPS JJ wy Xg gt s i 4 e e Q 2 K og pe S40 9NpUCS rass a5 0 VA O c Fig 1 BGU7004 GPS front end evaluation board UM10490 NXP B V 2011 All rights reserved User manual Rev 1 0 14 June 2011 3 of 19 NXP Semiconductors U M1 0490 BGU7004 GPS FE EVB 2 General description Modern cellular phones have multiple radio systems so problems like co habitation are quite common A GPS receiver implemented in a mobile phone requires the following factors to be taken into account All the different transmit signals that are active in a phone can cause problems like intermodulation and compression Since the GPS receiver needs to receive signals with an average power level of 130 dBm sensitivity is very important Currently there are several GPS chipsets on the market that can be implemented in cell phones PDAs etc Although many of these GPS ICs do have integrated LNA front ends the noise performance and as a result the system sensitivity is not always adequate The GPS receiver sensitivity is a measure for how accurate the coo
8. ation board 3 2 Board Layout Fig 3 Printed circuit board layout of the BGU7004 front end evaluation board UM10490 NXP B V 2011 All rights reserved User manual Rev 1 0 14 June 2011 5 of 19 NXP Semiconductors U M1 0490 3 3 BGU7004 GPS FE EVB PCB layout A good PCB layout is an essential part of an RF circuit design The front end evaluation board of the BGU7004 can serve as a guideline for laying out a board using the BGU7004 Use controlled impedance lines for all high frequency inputs and outputs Bypass Vcc with decoupling capacitors preferably located as close as possible to the 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 ain 0 2mm FR4 critical 20um Cu 0 8mm FR4 only for 20um Cu mechanical rigidity of PCB 1 Material supplier is ISOLA DURAVER er 4 6 4 9 Tan 0 02 Fig 4 Stack of the PCB material 4 Bill of materials Table 1 BOM of the BGU7004 GPS front end evaluation board Designator Ac
9. dBm to avoid activating the adaptive biasing This low input level results in a very inaccurate measurement result of the TX rejection which can be seen on the results pages attached to the evaluation boards In Fig 15 and Fig 16 one can see the typical TX rejection levels measured more accurate due to segmented power calibration This is the typical result of 15 EVBs Typical BGU7005 FE performance Vec 1 8V PCS band rejection gt 90dBe Cell band rejection gt 95dBe Gain Input RL Output RL GHz Fig 15 Typical S parameter Plot Vcc 1 8V Icc 4 7mMA Typical BGU7005 FE performance Vec 1 8V 20 Gain Input RL Output RL 25 30 1 50 1 52 1 54 1 56 1 58 1 60 1 62 Freq 1 64 GHz Fig 16 Pass band response of typical S parameter Plot Vcc 1 8V Icc 4 7mA UM10490 NXP B V 2011 All rights reserved User manual Rev 1 0 14 June 2011 16 of 19 NXP Semiconductors UM10490 10 Typical front end evaluation board results BGU7004 GPS FE EVB Table 2 typical results measured on the evaluation boards Operating Frequency is f 1575 42 MHz unless otherwise specified Temp 25 C Parameter Supply Voltage Supply Current Noise Figure Power Gain Input Return Loss Output Return Loss Reverse Isolation Input 1dB Gain Compression Input 1dB Gain Compression jammer level at 850MHz Input 1dB Gain Compression jamm
10. e been used to measure the IM3 levels on the front end evaluation board were 10 dBm see Fig 7 Fig 8 shows the IM3 level at the output of the front end measured at Ve 1 8 V NXP B V 2011 All rights reserved User manual Rev 1 0 14 June 2011 11 of 19 NXP Semiconductors U M1 0490 BGU7004 GPS FE EVB RBW 3 MHz RBW 20 kHz VBW 3 kHz Marker 1 T1 9 99 dBm 1 7132 GHz Q VBW 30 Hz Marker 1 T1 83 79 dBm 1 57542 GHz Ref 20 dam Att 45 cB SWE 70 ms Marker 2 T1 10 02 dBm 1 8514 GHz Ref 50 dan Att 5 dB SWE 3 4s 20 50 1 2 10 60 0 70 10 80 20 a ad 100 40 110 120 00 130 2 140 80 150 Center 1 78092 GHz 25 MHz Span 250 MHz Center 1 57542 Giz 100 Kiz Span 1 Miz Fig 7 Input jammers for IM3 measurements L1 138 Fig 8 FE output IM3 level at 1575 42MHz MHz L1 276 MHz With the levels shown in Fig 7 and Fig 8 the out of band input third order intercept point can be calculated Pin of f4 and f2 10 dBm see Fig 7 Left side output IM3 83 8 a 1575 42 MHz see Fig 8 Gain of the front end 14 6d IIM 3 OIM3 gain 83 B Bm 14 6 dB 98 4 dBm Delta P f1 IIM3 10 98 4 108 4dB O _IIP3 pgp 2A O IIP3 10 64 2dBm UM10490 NXP B V 2011 All rights reserved User manual Rev 1 0 14 Ju
11. er level at 1850MHz Cell band rejection relative to 1575 42MHz 850MHz PCS band rejection relative to 1575 42MHz 1850MHz Input third order intercept point Power settling time Symbol Vec lec NF Gp RLin RLout ISOrev Pi1dB Pi1dBesomuz Pi1dB1gsomuz TX rej TX rej IP3 Ton Toff FE EVB 1 5 4 5 1 78 14 4 8 6 17 6 27 7 1 4 FE EVB FE EVB 1 8 2 85 4 6 5 1 1 78 1 79 14 6 14 9 8 7 9 3 18 1 18 4 24 9 25 4 8 2 6 4 31 40 gt 95 gt 90 64dB 1 0 9 0 95 0 9 Unit Remarks V mA dB dB dB dB dB dBm dBm dBm dBc dBc dBm us 1 The noise figures and gain figures are being measured at the SMA connectors of the evaluation board so the losses of the connectors and the PCB of approximately 0 1dB are not subtracted 2 These parameters are mainly determined by the TX rejection levels of the used BPFs in this case the Murata SAFEA1G57KEOFOO but the performance can also be achieved with the use of GPS SAW filters from other suppliers that are on the market See paragraph 4 2 3 Note3 Jammers at f1 f 138 MHz and f2 f 276 MHz where f 1575 42 MHz UM10490 NXP B V 2011 All rights reserved User manual Rev 1 0 14 June 2011 17 of 19 NXP Semiconductors UM10490 11 Legal information BGU7004 GPS FE EVB 11 1 Definitions Draft The document is a draft version only The content is still under int
12. ernal 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 11 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 t
13. his 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 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 a
14. iconductors UM10490 12 Contents BGU7004 GPS FE EVB 3 1 3 2 3 3 4 1 4 2 4 3 7 1 7 2 10 11 11 1 11 2 11 3 12 Introduction ees 3 General GeSCription ccccccessseseseeeeessereeeeeees 4 BGU7004 GPS front end evaluation board 4 Application Circuit 4 Board Layout ee eecceceeeeeeeeeneeeeeeeeeeeesnaeeeeeeaas 5 PCB layout innsinn bee 6 Bill Of Mate rialS cccessseeeeeseeeeseeeeeeeseeeeeeeeeeees 6 BGW 7004 i iiicsccndecsceetaluenhesdevetecnlbecbenstuncrevabeeek shee 7 Band pass filters ee eeneeeeeeneeeeeeneeeeeeneeeeeeaas 7 Ser s INAUCHON isinne ia 8 Required Equipment ssssssssusssnnnrernnernnnnnnnnnnennne 9 Connections and Setup cccssseseeeeeeeeeeees 10 Linearity 200 cece ee neeeee ee neeeeeeeseeeenneeeeeennseneeeeeees 11 Out of band input third order intercept point 11 In band 1dB gain compression due to 850MHz and 1850MHZ jAMMETS 1000 eee eee ee eee eeeeenteeeeeenes 13 Noise figure as function of jammer power at B50MHZ and 1850MHZ cccccessseeeeeeeeeeneeeeees 14 TX rejection levels ccccseseeeesseeesseeennseeeees 16 Typical front end evaluation board results 17 Legal information ccccscccssseeseeeeeeessereeeeeees 18 DefiMitiONS esisiini enine ieseana baa ee 18 DISCIAING Scissors te adzerteann te snesececepantt seeded seeteee 18 Trademarks seccecccteveeesant ce Gecteunls ot iessbectoeedeeesae enters 18 O01 ee 19 P
15. lease 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 2011 All rights reserved For more information please visit http www nxp com For sales office addresses email to salesaddresses nxp com Date of release 14 June 2011 Document identifier UM10490
16. level 4 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 Please note the values of RBW and VBW in the related figures for the exact settings 5 Turn on the DC power supply and it should read approximately 5mA 6 Enable the RF output of the generator The spectrum analyzer displays a tone of around 25 dBm at 1575 42 MHz 7 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 8 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 performance 9 For noise under jamming conditions the following is needed A 15 dB ENR noise source a directional coupler GPS band pass filter a noise figure analyzer or a spectrum analyzer with noise option can be used See Fig 12 UM10490 NXP B V 2011 All rights reserved User manual Rev 1 0 14 June 201
17. lly matched for 1575 42 MHz whereas only one series inductor at the input is needed to achieve the best RF performance Both the input and output are AC coupled via an integrated capacitor It requires only two external components to build a GPS LNA having the following advantages e Low noise e High gain e High linearity under jamming e Very low package height 0 5mm e Low current consumption e Short power settling time The BGU7004 data sheet is available and is called SiGe C Low Noise Amplifier MMIC for GPS 4 2 Band pass filters The band pass filters that are implemented in the GPS front end evaluation board are key components regarding the overall system linearity and sensitivity Currently there are different suppliers on the market that have SAW filters for the GPS band available One of the key performance indicators of these filters is having very high rejection at the different cell phone TX frequencies and simultaneously having low insertion loss in the GPS pass band Although the evaluation board is supplied with two Murata SAFEA1G57KEOF00 the following alternatives can be considered EPCOS 9444 Murata SAFA1G57KHOFOO Murata SAFA1G57 KBOFO0 low loss variant Fujitsu FAR F6KA 1G5754 L4AA 5 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 pro
18. ne 2011 12 of 19 NXP Semiconductors U M1 0490 UM10490 7 2 BGU7004 GPS FE EVB In band 1dB gain compression due to 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 an BGU7004 GPS Low noise amplifier evaluation board user manual available 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 GPS frequency band of 130dBm average will not cause linearity problems in the GPS band itself This of course is also valid for the 1dB gain compression in band The 1dB compression point at 1575 42MHz caused by cell phone TX jammers however is important Measurements have been carried out using the setup shown in Fig 9 D D CAB1 e Q S w w Ne ras BGU7004 GPS LNA EVB ao aes 20dB OCO Bieciond coer Fig 9 1dB Gain compression under jamming measurements setup The gain was measured in the GPS frequency band between port 1 and 2 while simultaneously a jammer power signal was swept on port 3 Please note that the drive power of the jammer is 20 dB l
19. ower at the input of the DUT caused by the directional coupler Fig 10 and Fig 11 show the gain compression curves with 850MHz and 1850MHz jammers respectively Calculating the power level at a the front end gain with 1 dB in compression is done as follows The analyzer read out for 850 MHz jammer is 9 3 dBm see Fig 10 taken into account the 20 dB attenuation of the directional coupler means 10 7dBm This is for the LNA NXP B V 2011 All rights reserved User manual Rev 1 0 14 June 2011 13 of 19 only NXP Semiconductors U M1 0490 BGU7004 GPS FE EVB Now using the typical rejection at 850MHz of the SAW filter which is 42dB the 1dB compression jammer signal level equals 10 7 42 31 3 dBm For 1850 MHz the read out is 14 42 dBm see Fig 11 taking into account the 20 dB attenuation of the directional coupler means 5 58 dBm Again this is for the LNA only Using the typical rejection at 1850MHz of the SAW filter which is 46 dB the 1dB compression jammer signal level equals 5 58 46 40 42dBm M1 25 00 dBm 16 289 dB amp M1 25 00 dBm 16 288 dB Trot dB Mag 1dB Ref16dB Cal int PCax M2 930 dBm 15 286 dB 4 Trc1 dB Mag 1dB Ref16dB Cal int PCax M2 14 42 dBm 15 289 dB 1 21 21 20 20 19 19 18 18 17 1 17 1 16 MZ lt 16 15 15 14 14 13 13 12 12 Ch1 Arb Channel Ba
20. perly 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 A OU N UM10490 NXP B V 2011 All rights reserved User manual Rev 1 0 14 June 2011 7 of 19 UM10490 NXP Semiconductors BGU7004 GPS 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 R 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 R the noise performance will degrade NXP B V 2011 All rights reserved 8 of 19 UM10490 User manual Rev 1 0 14 June 2011 NXP Semiconductors U M1 0490 BGU7004 GPS FE EVB 5 Required Equipment In order to measure the evaluation board the following is necessary v DC Power Supply up to 30 mA at 1 5 V to 2 85 V v Two RF signal generators capable of generating an RF signal at the operating frequency of 1575 42 MHz as well as the jammer frequencies 850 MHz 1713 42 MHz 1850 MHz and 1851 42 MHz v An RF spectrum analyzer that covers at least the operating frequency of
21. rdinates are calculated The GPS signal reception can be improved by a so called GPS front end which improves the sensitivity by filtering out the unwanted jamming signals and by amplifying the wanted GPS 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 GPS receiver 3 BGU7004 GPS front end evaluation board UM10490 3 1 The BGU7004 front end evaluation board simplifies the RF evaluation of the BGU7004 GPS LNA applied in a GPS front end that is often used in mobile cell phones The evaluation board enables testing of the device RF performance and requires no additional support circuitry The board is fully assembled with the BGU7004 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 BGU 7004 can operate from a 1 5 V to 2 85 V single supply and consumes about 5 mA 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 Ves or GND NXP B V 2011 All rights reserved User manual Rev 1 0 14 June 2011 4 of 19 NXP Semiconductors U M1 0490 BGU7004 GPS FE EVB Fig 2 Circuit diagram of the BGU7004 front end evalu
22. s for the planned UM10490 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 national 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 non infringement 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
23. se Start 25 dBm Freq 1 575 GHz Stop 15 dBm Ch1 Arb Channel Base Start 25 dBm Freq 1 575 GHz Stop 15 dBm Fig 10 1dB Gain compression 1 575 GHz 850 Mhz Fig 11 1dB Gain compression 1 575 GHz 1850 Mhz jammer 8 Noise figure as function of jammer power at 850MHz and 1850MHz UM10490 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 an BGU7004 GPS Low noise amplifier evaluation board user manual available 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 GPS antenna To measure this behavior the setup shown in Fig 12 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 GPS BPF is needed to avoid driving the second stage LNA in saturation NXP B V 2011 All rights reserved User manual Rev 1 0 14 June 2011 14 of 19 NXP Semiconductors U M1 0490 BGU7004 GPS FE EVB TX Jammer signal GEN1 Noise eh TCL sore PS Fig 12
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