AN11500 Highly Linear FM LNA design with BFU580G Rev. 1 — 16 June 2014 Application note Document information Info Content Keywords BFU580G, BFU580Q, BFU5xx series, FM band Abstract This document describes an FM band LNA design implemented on BFU580G/BFU590G Starter kit Ordering info BFU580G/BFU590G Starter-kit OM7966, 12nc 9340 678 75598 Contact information For more information, please visit: http://www.nxp.com AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G Revision history Rev Date Description 1 First publication 20140616 AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 2 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G 1. Abstract In this application note an FM band LNA design (low noise amplifier) using a BFU580G transistor from NXP latest wideband transistor range is described. It shows the design, simulation and implementation phases. Together with measurement results, parameters measured over temperature are shown. The application note (AN) can be a starting point for new design(s), and/or derivative designs. 2. Introduction The BFU500 series transistor family is designed to meet the latest requirements on high frequency applications (up to approximately 2 GHz) such as communication, automotive and industrial equipment. As soon as fast, low noise analogue signal processing is required, combined with medium to high voltage swings the BFU500 series transistors are the perfect choice. Due to the high gain at low supply current those types can also be applied very well in battery powered equipment. Compared to previous Philips / NXP transistor generations and competitor products, improvements on gain, noise and thermal properties are realized BFU500 series transistors are available in various packages. The transistors are promoted with a full promotion package, called “starter kits” (one kit type per packagetype). Those kits include two PCB’s (one with grounded emitter, one with emitter degeneration provision), RF connectors, transistors and simulation model parameters required to perform simulations. See the overview of available starter kits in the table below. Table 1. AN11500 Application note Customer evaluation kits Basic type Customer evaluation kits 1 BFU520W, BFU530W, BFU550W OM7960, starter kit for transistors in SOT323 package 2 BFU520A, BFU530A, BFU550A OM7961, starter kit for transistors in SOT23 package 3 BFU520, BFU530, BFU550 OM7962, starter kit for transistors in SOT143 package 4 BFU520X, BFU530X, BFU550X OM7963, starter kit for transistors in SOT143X package 5 BFU520XR, BFU530XR, BFU550XR OM7964, starter kit for transistors in SOT143XR package 6 BFU580Q, BFU590Q OM7965, starter kit for transistors in SOT89 package 7 BFU580G, BFU590G OM7966, starter kit for transistors in SOT223 package All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 3 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G Fig 1. BFU580G EVB picture 3. Requirements The demonstrator circuit is designed to show the BFU580G capabilities for a FM LNA with focus on Noise Figure and Linearity with supply current limited to maximum 25mA. The aim of the demonstrator circuit was to design a LNA optimized for the FM band (88 MHz to 108 MHz) for automotive equipment meeting following requirements: Supply Voltage: Supply current: Frequency range Noise Figure: Gain: OIP3: Input Return-Loss: Output Return-Loss: 5.0 Volts nominal approx. 20 mA to 25mA (at ambient temperature) 88 MHz – 108 MHz < 2dB approx. 20 dB > +15dBm > 10dB > 10dB The design is aimed at low BOM cost and small PCB area, inductors are SMD types (preferable low cost multilayer types) to enable simple tuning to other frequency bands. As the design should be usable for automotive / car entertainment applications the behavior over temperature should be monitored. AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 4 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G 4. Design considerations In order to achieve low Noise Figure and reasonable Gain the source impedance has to be in between the optimum for Noise Figure and maximum Gain with given biasing current. As the required BW is approximately 20% of the Centre Frequency high Q matching circuits are not preferred (may lead to significant gain variations in the band). The typical impedances in FM radio’s for RF are 75 Ohms, as our demonstrator utilizes 50 Ohms transmission lines and connectivity two versions could be simulated. At any time the circuit should be stable, hence during the design phase the stability factor needs to be observed carefully. 5. Design approach The design starts in the simulation phase, applying the Mextram Model (available at http://www.nxp.com ). Agilent “Advanced Design System” (ADS) was used for this but other simulation software packages should give equal results. Spice / Gummel Poon models are also available. In case simulations with Sparameter data have to be performed it is possible to download data from www.nxp.com. S-parameters data for various supply voltages and bias currents is available. Once simulation results meet the requirements, the circuit is built on a universal Printed Circuit Board (PCB) and evaluated. If measurement results show significant offset from simulated results, fine tuning is required until required performance is met. To achieve better matching between simulations and measurements, the PCB parasitic properties were added in the simulation template. Following blocks of passive components can be identified: 1) resistors for DC biasing 2) passives set up collector load 3) passives for output matching 4) passives for input matching 5) passives required to ensure stable operation 5.1 Simulation steps Following simulation / design approach can be useful: 1) Configure the DC bias set-up, ensuring the Icc is set around desired value. 2) Configure the collector load circuit and output matching circuitry, optimizing the output Return Loss (RL). 3) Check stability. 4) Configure the input matching, for LNA optimize for minimum noise figure (NF) but keep close to optimum gain, if possible optimum NF gain points should be close. 5) Check stability. Assumptions: - Realistic passives are used by applying Murata design kit (0805 / 0603) - PCB tracks represented by strip-lines AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 5 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G 5.2 Implementation / evaluation steps Following implementation / evaluation steps have been executed: 1) Implement simulated design on universal PCB. 2) Evaluate LNA on Gain / NF / matching / Stability at ambient temperature. 3) Fine tune passives if required. 4) In case significant differences between simulations and measured results are observed, try to modify parasitic properties in the simulation template. 5) Measure LNA design on RF parameters over temperature. 5.3 Setting up the DC bias circuit Vcc Vcc C2 C2 R3 R3 C3 R1 R2 Lcol C3 R1 R2 Lcol C1 Lbase DC bias circuit 1 DC bias circuit 2 Fig 2. Circuitry to set DC bias current Circuit 1 has the advantage that resistive noise from the resistors R1 and R2 is suppressed by capacitor C1, but at the cost of an extra inductor. This inductor can be part of the input matching. Circuit 2 is commonly used and saves two passive components. Both circuits tend to have increasing collector current (Icc) with increasing temperature, partly stabilized by R3. Increasing R3 will degrade the linearity as it lowers the Vc. AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 6 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G 5.4 Described design versions Table 2. Version: Different versions simulated 1 2 3 3 applying input match Typical Zin/Zout 75Ω 50Ω 75Ω 75Ω Feedback No Yes Yes Yes Selectivity Medium Small Medium Small Built/tested No Yes No No 5.5 Version 1, 75 Ohms selective LNA The configuration used and simulation display is shown below (ADS). Fig 3. FM LNA version 1, applied ADS schematic This is the schematic applied for S-parameter simulations. At the input there are no additional matching components used, still the input return loss reaches levels >10 dB. The components L1, L4, C1 are tuned to get good match/gain match in the required frequency band. Inductor L3 represents the parasitic inductance in the emitter path to ground (PCB related). Please note that for simulations BFU590Q is used, this is the same transistor as BFU590G (apart from the package). The simulation results of these two types are similar at the FM band frequencies. AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 7 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G Fig 4. Version 1 S-parameter simulation results The gain is above 20dB. There is a steep roll off for higher frequencies which can be advantageous in case large signals outside the FM band have to be suppressed. For example the suppression of the lowest LTE band (728 MHz) is 37 dB. At 5.0 Volts supply the simulated supply current is 22mA. Also note that there are no additional matching components used at the input. The input-return-loss as well as the output-return-loss is more than 10dB. AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 8 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G Simulating the Noise and Gain behavior gives the results as shown in figure 5. Fig 5. Version 1, Noise Figure, Noise circles For better Noise Figure an additional network that matches the source towards the optimum (lower than 75 Ohms) could be used, however simulations show that this significantly degrades the input matching. Fig 6. AN11500 Application note Version 1, Stability figures All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 9 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G 5.5.1 Version 1, linearity simulations Fig 7. ADS simulation set-up for IP3 A harmonic balance simulation template is used, spacing applied was 100 kHz. Fig 8. AN11500 Application note Version 1 IP3 simulation results All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 10 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G 5.5.2 Summary / conclusions on version 1 This version has some selectivity (approx 37 dB damping for lowest LTE band). To ensure the proper frequency band, an evaluation on the spread of used components and PCB tolerances have to be performed (i.e. Monte Carlo). The NF is approx 1.7 dB with a good input return-loss. The NF could be improved at the cost of the input reflection coefficient. AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 11 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G 5.6 Version 2, 50 Ohms LNA, applying feedback The configuration used and simulation display is shown below (ADS). Fig 9. FM LNA version 2, applied ADS schematic This is the schematic applied for S-parameter simulations. At the input there are no additional matching components used, still the input reflection reaches levels < -10 dB. The components R5, C12 are used to generate feedback. The micro-strip lines used represent the copper patterns of applied PCB. AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 12 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G Fig 10. Version 2 S-parameter simulation results The gain is above 20dB. At 5.0 Volts supply the simulated supply current is 25mA. Also note that there are no additional matching components used at the input. The input-return-loss is more than 10dB, the output-return-loss >20dB. AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 13 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G Fig 11. Version 2, Noise Figure, Noise circles For better Noise Figure an additional network that matches the source towards the optimum could be used, however simulations show that this significantly degrades the input matching. Fig 12. Version 2, Stability figures AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 14 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G 5.6.1 Version 2, linearity simulations Fig 13. ADS simulation set-up for IP3 A harmonic balance simulation template is used, spacing applied was 5 kHz. Fig 14. Version 2 IP3 simulation results AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 15 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G 5.6.2 Summary / conclusions on version 2 This version 2 has price advantages compared to version 1, as the required passives are only resistors and capacitors. The NF is approx 1.6 dB with a good input return-loss. The NF could be improved at the cost of the input reflection coefficient. The version 2 is implemented on the universal PCB, as delivered in the starter-kit. This PCB is equipped with SMA (50 Ohms) connectors. A similar 75 Ohms version, called version 3, applying feedback is designed in ADS. Results are shown in sections 5.7. AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 16 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G 5.7 Version 3, 75 Ohms LNA, applying feedback The configuration used and simulation display is shown below (ADS). Fig 15. FM LNA version 3, applied ADS schematic This is the schematic applied for S-parameter simulations. At the input there are no additional matching components used, still the input return loss reaches levels >10 dB. The components R5/C12 are used to generate feedback, components.L4/C19 are used to match the output. AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 17 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G Fig 16. Version 3 S-parameter simulation results The gain is above 20dB, at 5.0 Volts supply the simulated supply current is 25mA. Due to the additional output matching section (L4, C19) there is more rejection, compared to version 2, for frequencies above the FM band. As an example marker 8 is shown at a lower LTE band. Simulating the Noise and Gain behavior gives the results as shown in figure 17. AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 18 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G Fig 17. Version 3, Noise Figure, Noise circles For better Noise Figure an additional network that matches the source towards the optimum could be used, but this will most likely degrade the input matching performance.. Fig 18. Version 3, Stability figures AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 19 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G 5.7.1 Version 3, linearity simulations Fig 19. ADS simulation set-up for IP3 A harmonic balance simulation template is used, spacing applied was 5 kHz. Fig 20. IP3 simulation results AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 20 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G 5.7.2 Optimizing version 3 for best Noise Figure By applying an input match that creates source impedance close to the optimum for Noise Figure, we could optimize the design for Noise Figure, with a possible trade-off for other parameters. The optimum source impedance can be seen in figure 17 and has to be smaller than 75Ω with imaginary part close to zero. The figure below shows the input configuration used that tunes the source impedance towards the optimum for lowest noise figure (components used for tuning are L5 and C20). Fig 21. ADS simulation schematic for source matching In the figure below the simulated source impedance is shown. Fig 22. Simulated source impedance for input matched version 3 AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 21 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G When simulating the LNA including the input network for noise we get the plot as shown below: Fig 23. Simulated Noise Figure for input matched version 3 Now clearly the optimum for noise has moved towards the ideal 75Ω point and the optimum for gain is also not too far off. Simulated Noise Figure is now 1.1 to 1.2 dB. Simulated S-parameters are show in the next graph. AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 22 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G Fig 24. Simulated S-pars for input matched version 3 The gain is comparable with previous version. The output matching can be considered as moderate, to obtain that the matching network at the output was removed. The linearity simulations showed almost equal behavior as the version without input matching, OIP3 simulated is18.9dBm. 5.7.3 Summary / conclusions on version 3 For this design the 50Ω version (version 2) is taken as starting point, a conversion to 75Ω is simulated. The version with source matching is best for lowest Noise Figure (approx. 1.2dB), the version with output matching has more rejection for “out of band” frequencies (i.e. LTE bands) but Noise Figure is almost 1dB higher. For linearity both versions show equal performance. . AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 23 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G 6. Implementation on starter-kit The circuit diagram of the evaluation board that was build and evaluated over temperature is shown in figure 25. Version 2, as described in sections 5.6, was used. 6.1 BFU580G FM LNA schematic Vcc 5V 47nF 330pF 68R 47nF 330pF 56R 8.2k 1.2k 330pF 330pF RF input (SMA) 330pF RF output (SMA) BFU580G BFU580G FM LNA Version V4, Jan 2014 Fig 25. Schematic for measured LNA version The PCB layout used for our internal evaluations did not accommodate the DC feed after the 68Ω resistor towards the 56Ω collector resistor, so a piece of wire was manually placed as show in the PCB drawing in figure 23. Please note that not-used components (0R or jumpers that are present on the PCB design to allow different input configurations) in series with the signal path at the LNA input might cause additional input loss that adds to the Noise Figure. AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 24 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G 6.2 BFU580Q FM LNA, PCB drawing Fig 26. PCB and component placement for evaluated version Remarks: 0R = SMD jumper, NM = not mounted NM = component not mounted. A connection from point A to B has to be made for the Collector Bias as shown. 6.1 PCB properties, layer stack Fig 27. PCB layers used for Evaluation Boards in Starter kit AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 25 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G 6.1 Typical LNA evaluation board results Table 3. Typical results measured on the evaluation boards Operating Frequency is f = 98 MHz unless otherwise specified; Temp = 25 °C Parameter Symbol EVB Unit Remarks Supply Voltage VCC 5.0 V Supply Current ICC 25 mA NF 1.6 dB Power Gain Gp 22 dB Input Return Loss RLin -15 dB Output Return Loss RLout -11 dB Output third order intercept point OIP3 +15 dBm Noise Figure Table 4. Bill Of Materials Value Description Footprint Manufacturer BFU580Q Transistor SOT89 NXP Semiconductors 330 pF Capacitor 0603 Various 330 pF Capacitor 0603 Various 330 pF Capacitor 0603 Various 330 pF Capacitor 0603 Various 330 pF Capacitor 0603 Various 47 nF Capacitor 0603 Various 47 nF Capacitor 0603 Various 56 Ω Resistor 0603 Various 68 Ω Resistor 0603 Various 1.2 kΩ Resistor 0603 Various 8.2 kΩ Resistor 0603 Various AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 26 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G 6.2 Simulation versus measured results Fig 28. Version 2, measured versus simulated S-pars AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 27 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G 7. Characterization of LNA over temperature and supply voltage 7.1 Gain (S21) = f (freq) Fig 29. Measured S21 over frequency for different temperatures 7.2 Input return-loss (S11) = f (freq) Fig 30. Measured S11 over frequency for different temperatures AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 28 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G 7.3 Output return-loss (S22) = f (freq) Fig 31. Measured S22 over frequency for different temperatures 7.4 Isolation (S12) = f (freq) Fig 32. Measured S12 over frequency for different temperatures AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 29 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G 7.5 Output third-order intercept point (OIP3) = f (Tamb) Fig 33. Measured OIP3 over temperature for different supply voltages 7.6 Noise Figure = f (Freq) Fig 34. Measured Noise Figure over frequency for different temperatures AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 30 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G 8. Conclusions / recommendations Witt the BFU580G a simple and cheap FM band LNA design with NF close to 1.6 dB with IOP3 0f +15 dBm in 50Ω system can be implemented. The LNA draws approximately 23 mA and has good input and output matching properties. In case a 75Ω LNA is required design version 3 can be used, the NF that can be achieved is 1.2 dB and OIP3 +19 dBm at 25 mA supply current. Shown circuits can be used as a base for derivative designs. Matching to other frequencies can be done by tuning relevant capacitors and inductors. 9. References BFU58G datasheet BFU5xxG starter-kit User Manual, UM10772 10. Abbreviations LNA FM AN PCB RF OIP3 NF BOM SMD DC AN11500 Application note Low Noise Amplifier Frequency Modulation Application Note printed Circuit Board Radio Frequency Third order Output Intersection Point Noise Figure Bill of Materials Surface Mounted Devices Direct Current All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 31 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G 11. Legal information 11.1 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. 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. 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 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 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. AN11500 Application note 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. 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. 11.3 Licenses Purchase of NXP <xxx> components <License statement text> 11.4 Patents Notice is herewith given that the subject device uses one or more of the following patents and that each of these patents may have corresponding patents in other jurisdictions. <Patent ID> — owned by <Company name> 11.5 Trademarks Notice: All referenced brands, product names, service names and trademarks are property of their respective owners. <Name> — is a trademark of NXP B.V. All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 32 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G 12. 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. Fig 20. Fig 21. Fig 22. Fig 23. Fig 24. Fig 25. Fig 26. Fig 27. Fig 28. Fig 29. Fig 30. Fig 31. Fig 32. Fig 33. Fig 34. BFU580G EVB picture ...................................... 4 Circuitry to set DC bias current ......................... 6 FM LNA version 1, applied ADS schematic ...... 7 Version 1 S-parameter simulation results ......... 8 Version 1, Noise Figure, Noise circles .............. 9 Version 1, Stability figures................................. 9 ADS simulation set-up for IP3 ......................... 10 Version 1 IP3 simulation results ...................... 10 FM LNA version 2, applied ADS schematic .... 12 Version 2 S-parameter simulation results ....... 13 Version 2, Noise Figure, Noise circles ............ 14 Version 2, Stability figures............................... 14 ADS simulation set-up for IP3 ......................... 15 Version 2 IP3 simulation results ...................... 15 FM LNA version 3, applied ADS schematic .... 17 Version 3 S-parameter simulation results ....... 18 Version 3, Noise Figure, Noise circles ............ 19 Version 3, Stability figures............................... 19 ADS simulation set-up for IP3 ......................... 20 IP3 simulation results ...................................... 20 ADS simulation schematic for source matching ........................................................................ 21 Simulated source impedance for input matched version 3 ......................................................... 21 Simulated Noise Figure for input matched version 3 ......................................................... 22 Simulated S-pars for input matched version 3 23 Schematic for measured LNA version............. 24 PCB and component placement for evaluated version ............................................................ 25 PCB layers used for Evaluation Boards in Starter kit......................................................... 25 Version 2, measured versus simulated S-pars 27 Measured S21 over frequency for different temperatures ................................................... 28 Measured S11 over frequency for different temperatures ................................................... 28 Measured S22 over frequency for different temperatures ................................................... 29 Measured S12 over frequency for different temperatures ................................................... 29 Measured OIP3 over temperature for different supply voltages ............................................... 30 Measured Noise Figure over frequency for different temperatures ..................................... 30 AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 33 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G 13. List of tables Table 1. Table 2. Table 3. Table 4. Customer evaluation kits ................................... 3 Different versions simulated .............................. 7 Typical results measured on the evaluation boards ............................................................. 26 Bill Of Materials ............................................... 26 AN11500 Application note All information provided in this document is subject to legal disclaimers. Rev. 1 — 16 June 2014 © NXP B.V. 2014. All rights reserved. 34 of 35 AN11500 NXP Semiconductors Highly Linear FM LNA design with BFU580G 14. Contents 1. 2. 3. 4. 5. 5.1 5.2 5.3 5.4 5.5 5.5.1 5.5.2 5.6 5.6.1 5.6.2 5.7 5.7.1 5.7.2 5.7.3 6. 6.1 6.2 6.1 6.1 6.2 7. 7.1 7.2 7.3 7.4 7.5 7.6 8. 9. 10. 11. 11.1 11.2 11.3 11.4 11.5 12. Abstract ................................................................ 3 Introduction ......................................................... 3 Requirements ...................................................... 4 Design considerations ........................................ 5 Design approach ................................................. 5 Simulation steps ................................................. 5 Implementation / evaluation steps ...................... 6 Setting up the DC bias circuit ............................. 6 Described design versions ................................. 7 Version 1, 75 Ohms selective LNA..................... 7 Version 1, linearity simulations ......................... 10 Summary / conclusions on version 1................ 11 Version 2, 50 Ohms LNA, applying feedback ... 12 Version 2, linearity simulations ......................... 15 Summary / conclusions on version 2................ 16 Version 3, 75 Ohms LNA, applying feedback ... 17 Version 3, linearity simulations ......................... 20 Optimizing version 3 for best Noise Figure....... 21 Summary / conclusions on version 3................ 23 Implementation on starter-kit ........................... 24 BFU580G FM LNA schematic .......................... 24 BFU580Q FM LNA, PCB drawing .................... 25 PCB properties, layer stack .............................. 25 Typical LNA evaluation board results ............... 26 Simulation versus measured results ................ 27 Characterization of LNA over temperature and supply voltage ................................................... 28 Gain (S21) = f (freq) ......................................... 28 Input return-loss (S11) = f (freq) ....................... 28 Output return-loss (S22) = f (freq) .................... 29 Isolation (S12) = f (freq) ................................... 29 Output third-order intercept point (OIP3) = f (Tamb) ............................................................. 30 Noise Figure = f (Freq) ..................................... 30 Conclusions / recommendations ..................... 31 References ......................................................... 31 Abbreviations .................................................... 31 Legal information .............................................. 32 Definitions ........................................................ 32 Disclaimers....................................................... 32 Licenses ........................................................... 32 Patents ............................................................. 32 Trademarks ...................................................... 32 List of figures..................................................... 33 13. 14. List of tables ......................................................34 Contents .............................................................35 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. 2014. 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: 16 June 2014 Document identifier: AN11500