AN11223 Low Noise Fast Turn ON/OFF 2.4-2.5GHz WiFi LNA with BFU730LX Rev. 2 — 16 November 2012 Application note Document information Info Content Keywords BFU730LX, 2.4-2.5GHz LNA, WiFi (WLAN) Abstract This document provides circuit simulation, schematic, layout, BOM and typical EVB performance for a 2.4-2.5GHz WiFi (WLAN) LNA AN11223 NXP Semiconductors Low Noise Fast Turn ON/OFF 2.4-2.5GHz WiFi LNA with BFU730LX Revision history Rev Date Description 2 20121116 New publication 1 20120703 Initial Draft Contact information For additional information, please visit: http://www.nxp.com For sales office addresses, please send an email to: [email protected] AN11223 Application note All information provided in this document is subject to legal disclaimers. Rev. 2 — 16 November 2012 © NXP B.V. 2012. All rights reserved. 2 of 21 AN11223 NXP Semiconductors Low Noise Fast Turn ON/OFF 2.4-2.5GHz WiFi LNA with BFU730LX 1. Introduction The BFU730LX is a discrete HBT that is produced using NXP Semiconductors’ advanced 110 GHz fT SiGe:C BiCmos process. SiGe:C is a normal silicon germanium process with the addition of Carbon in the base layer of the NPN transistor. The presence of carbon in the base layer suppresses the boron diffusion during wafer processing. This allows a steeper and narrower SiGe HBT base and a heavier doped base. As a result, lower base resistance, lower noise and higher cut off frequency can be achieved. The BFU730LX is one of a series of transistors made in SiGe:C. BFU710F, BFU730F, BFU760F, BFU768F and BFU790F are the other types. BFU710F is intended for ultra low current applications. The BFU760F, BFU768F and BFU790F are high current types and are intended for application where linearity is key. New 6th & 7th Generation Wideband transistors from NXP offer best RF noise figure / gain tradeoff at 12GHz drawing lowest current which means best signal reception at low power, enabling products to be more sensitive in noisy environments and friendlier to the environment. Key Benefits: • Application up to 18 GHz and higher • Broad choice of parts for the perfect fit in the application • Lowest current consumption meaning greener products • SOT883C for BFU730LX and for the others SOT343F package for high performance and easy manufacturing AN11223 Application note All information provided in this document is subject to legal disclaimers. Rev. 2 — 16 November 2012 © NXP B.V. 2012. All rights reserved. 3 of 21 AN11223 NXP Semiconductors Low Noise Fast Turn ON/OFF 2.4-2.5GHz WiFi LNA with BFU730LX Fig 1. BFU730LX Universal Demo Board 2.4-2.5GHz WiFi LNA EVB Demo Board 2. Requirements and design of the 2.4-2.5GHz WiFi LNA The circuit shown in this application note is intended to demonstrate the performance of the BFU730LX in a 2.4-2.5 GHz LNA for e.g. 802.11a/b/g/n & 802.11ac “MIMO” WiFi (WLAN) applications. Key requirements for this application are: AN11223 Application note • Frequency Band 2.4 – 2.5GHz • Gain • Input/output Match • Linearity • NF • Turn ON/OFF Time All information provided in this document is subject to legal disclaimers. Rev. 2 — 16 November 2012 © NXP B.V. 2012. All rights reserved. 4 of 21 AN11223 NXP Semiconductors Low Noise Fast Turn ON/OFF 2.4-2.5GHz WiFi LNA with BFU730LX 3. Design and Simulation The 2.4-2.5 GHz WiFi LNA consists of one stage BFU730LX amplifier. The design has been simulated, and the simulation results are given in the following figures. The LNA shows excellent match at input/output with greater than 10dB return loss and gain of 17 @2.45GHz with superior Noise Figure of 0.97dB. With only 12.5mA it also shows a high input P1 dB compression of -9 [email protected], as well as high input IP3 of +2dBm. The LNA Turn ON and OFF time are 380nS and 40 nS respectively. The designed LNA is unconditionally stable at 10 MHz-15 GHz. 3.1 BFU730LX 2.4-2.5GHz WiFi LNA Simulation Fig 2. AN11223 Application note BFU730LX 2.4-2.5GHz WiFi LNA Simulation: Circuit (Capacitors GRM1555 & Inductors LQP15) All information provided in this document is subject to legal disclaimers. Rev. 2 — 16 November 2012 © NXP B.V. 2012. All rights reserved. 5 of 21 AN11223 NXP Semiconductors Low Noise Fast Turn ON/OFF 2.4-2.5GHz WiFi LNA with BFU730LX 3.2 BFU730LX 2.4-2.5GHz WiFi LNA Simulation Result 3.2.1 Gain and Match in 2.4-2.5GHz Band Fig 3. AN11223 Application note BFU730LX 2.4-2.5GHz WiFi LNA Simulation: Gain and Match All information provided in this document is subject to legal disclaimers. Rev. 2 — 16 November 2012 © NXP B.V. 2012. All rights reserved. 6 of 21 AN11223 NXP Semiconductors Low Noise Fast Turn ON/OFF 2.4-2.5GHz WiFi LNA with BFU730LX 3.2.2 Noise Figure in 2.4-2.5GHz Band Fig 4. AN11223 Application note BFU730LX 2.4-2.5GHz WiFi LNA Simulation: Noise Figure All information provided in this document is subject to legal disclaimers. Rev. 2 — 16 November 2012 © NXP B.V. 2012. All rights reserved. 7 of 21 AN11223 NXP Semiconductors Low Noise Fast Turn ON/OFF 2.4-2.5GHz WiFi LNA with BFU730LX 3.2.3 Stability Fig 5. BFU730LX 2.4-2.5GHz WiFi LNA Simulation: Stability 4. Application Board The 2.4-2.5GHz WiFi LNA evaluation board simplifies the evaluation of the BFU730LX application. The evaluation board enables testing of the device performance and requires no additional support circuitry. The board is fully assembled with the BFU730LX transistor, including input and output matching components, to optimize performance. The board is supplied with two SMA connectors for input and output connection to RF test equipment. AN11223 Application note All information provided in this document is subject to legal disclaimers. Rev. 2 — 16 November 2012 © NXP B.V. 2012. All rights reserved. 8 of 21 AN11223 NXP Semiconductors Low Noise Fast Turn ON/OFF 2.4-2.5GHz WiFi LNA with BFU730LX 4.1 Application Circuit Schematic AN11223 Application note Fig 6. BFU730LX Universal Demo Board: Schematic Fig 7. BFU730LX 2.4-2.5GHz WiFi LNA: Schematic All information provided in this document is subject to legal disclaimers. Rev. 2 — 16 November 2012 © NXP B.V. 2012. All rights reserved. 9 of 21 AN11223 NXP Semiconductors Low Noise Fast Turn ON/OFF 2.4-2.5GHz WiFi LNA with BFU730LX Note: Figure 6 is the schematic for BFU730LX universal demo board, some assembly changes are made to accommodate this simplified design, the revised schematic is shown in figure 7, and the changes in figure 6 are as following: 1. C1, C4, C6, C7, C8, C10: not populated 2. Move R1 (36K) to L1 location, short two solder pads of R1 or put a 0 ohm jumper 3. Move C3 (1pF) to L3 location, short two solder pads of C3 or put a 0 ohm jumper 4.2 Application Board Bill-Of-Material Table 1. BFU730LX 2.4-2.5GHz WiFi LNA Part List Customer can choose their preferred vendor but should be aware that the performance could be affected. AN11223 Application note Item Position on Layout Reference (Fig 7) Type Vendor Value 1 Z2 C1 GRM1555C1 Murata 33pF 2 Z5 C2 GRM1555C1 Murata 1.0pF 3 Z16 C3 GRM1555C1 Murata 2.7pF 4 Z13 C4 GRM1555C1 Murata 180pF 5 Z4 L1 LQP15 Murata 4.7nH 6 Z3 R1 36K 7 Z10 R2 0R 8 Z14 R3 22R 9 Z12 R4 39R 10 Z6 R5 11 Z18 12 X1, X2 BFU730LX RF_IN, RF_OUT 13 X3 Vcc All information provided in this document is subject to legal disclaimers. Rev. 2 — 16 November 2012 0R NXP SEMICONDUCTORS Amphenol BFU730LX CONSMA-1 Molex CON-2PIN © NXP B.V. 2012. All rights reserved. 10 of 21 AN11223 NXP Semiconductors Low Noise Fast Turn ON/OFF 2.4-2.5GHz WiFi LNA with BFU730LX 4.3 Typical Application Board Test Result 4.3.1 S-Parameter – Gain and Match Fig 8. AN11223 Application note BFU730F 2.4-2.5GHz WiFi LNA: S-Parameter All information provided in this document is subject to legal disclaimers. Rev. 2 — 16 November 2012 © NXP B.V. 2012. All rights reserved. 11 of 21 AN11223 NXP Semiconductors Low Noise Fast Turn ON/OFF 2.4-2.5GHz WiFi LNA with BFU730LX 4.3.2 Linearity/IP3 Ref -6.4 dBm -10 1 SA VIEW Offset * Att 3.6 dB 10 dB * R BW 5 0 k H z V BW 2 00 k H z S WT 2 .5 m s 2 1 -20 -30 -40 Marker 2 [T1 ] - 13 . 03 d B m 2 . 4 5 0 9 96 7 95 G H z TOI 19 . 67 Marker 1 [T1 ] - 13 . 13 2 . 4 4 9 9 95 1 92 Marker 3 [T1 ] - 78 . 34 2 . 4 4 8 9 93 5 90 Marker 4 [T1 ] - 78 . 81 2 . 4 5 1 9 98 3 97 dBm dBm GHz A dBm LVL GHz dBm GHz -50 -60 3DB -70 3 4 -80 -90 -100 Center 2 . 4 5 0 5 GH z 500 kHz/ S p an 5 MHz Two tones: f1: 2450MHz, f2: 2451MHz, -30dBm each tone, tone spacing: 1MHz OIP3 = 19.5dBm IIP3 = OIP3 - Gain = 19.5 -17 = 2.5dBm Fig 9. AN11223 Application note BFU730LX 2.4-2.5GHz WiFi LNA: IP3 All information provided in this document is subject to legal disclaimers. Rev. 2 — 16 November 2012 © NXP B.V. 2012. All rights reserved. 12 of 21 AN11223 NXP Semiconductors Low Noise Fast Turn ON/OFF 2.4-2.5GHz WiFi LNA with BFU730LX 4.3.3 Stability K Factor Fig 10. BFU730LX 2.4-2.5GHz WiFi LNA: Stability 4.3.4 Noise Figure Measurement The noise figure is measured at the SMA connectors of the evaluation board. The losses of the connectors and the pcb are around 0.36dB @ 2.45GHz (RF_IN to RF_OUT). After de-embedding the connector and pcb losses (0.18dB @ 2.45GHz) up to the transistor input, the noise figure is 0.79dB @ 2.45GHz. AN11223 Application note All information provided in this document is subject to legal disclaimers. Rev. 2 — 16 November 2012 © NXP B.V. 2012. All rights reserved. 13 of 21 AN11223 NXP Semiconductors Low Noise Fast Turn ON/OFF 2.4-2.5GHz WiFi LNA with BFU730LX 4.3.5 LNA Turn ON/OFF Time The following diagram shows the setup to test LNA Turn ON and Turn OFF time. The LNA Turn ON and Turn OFF time are mainly determined by the R-C time constant of the biasing circuitries: R4*C4…Reducing the C4 can improve switching time speed. Set the waveform generator to square mode and the output amplitude at 3Vrms with high output impedance. The waveform generator has adequate output current to drive the LNA therefore no extra DC power supply is required which simplifies the test setup. Set the RF signal generator output level to -25dBm at 2.4GHz and increase its level until the output DC on the oscilloscope is at 25mV on 5mV/division, the signal generator RF output level is approximately -12dBm. It is very important to keep the cables as short as possible at input and output of the LNA so the propagation delay difference on cables between the two channels is minimized. It is also critical to set the oscilloscope input impedance to 50ohm on channel 2 so the diode detector can discharge quickly to avoid a false result on the Turn OFF time testing. Fig 11. LNA Turn ON and Turn OFF time test setup AN11223 Application note All information provided in this document is subject to legal disclaimers. Rev. 2 — 16 November 2012 © NXP B.V. 2012. All rights reserved. 14 of 21 AN11223 NXP Semiconductors Low Noise Fast Turn ON/OFF 2.4-2.5GHz WiFi LNA with BFU730LX 4.3.5.1 LNA Turn ON Time 3.0Vrms, 1kHz and 50% duty cycle pulse applied on VCC pin, measured from 50% of input pulse to 100% of max. output power Fig 12. BFU730LX 2.4-2.5GHz WiFi LNA: Turn ON time AN11223 Application note All information provided in this document is subject to legal disclaimers. Rev. 2 — 16 November 2012 © NXP B.V. 2012. All rights reserved. 15 of 21 AN11223 NXP Semiconductors Low Noise Fast Turn ON/OFF 2.4-2.5GHz WiFi LNA with BFU730LX 4.3.5.2 LNA Turn OFF Time 3.0Vrms, 1kHz and 50% duty cycle pulse applied on VCC pin, measured from 50% of input pulse to 0% of max. output power Fig 13. BFU730LX 2.4-2.5GHz WiFi LNA: Turn OFF time 4.3.6 Summary Of the Typical Evaluation Board Test Result Table 2. Typical results measured on the BFU730LX 2.4-2.5GHz WiFi LNA Evaluation Board Operating frequency 2.4-2.5GHz, testing at 2.4GHz and 2.5GHz unless otherwise specified, Temp = 25°C. All measurements are done with SMA-connectors as reference plane. Parameter Symbol Value Unit Supply Voltage Vcc 3.0 V Supply Current Icc 12.5 mA @2.4GHz NF 0.79 dB @2.5GHz NF 0.79 dB Power Gain @2.4GHz Gp 16.9 dB @2.5GHz Gp 17.0 dB Input Return Loss @2.4GHz IRL 11.5 dB @2.5GHz IRL 12.6 dB Noise Figure AN11223 Application note [1] All information provided in this document is subject to legal disclaimers. Rev. 2 — 16 November 2012 © NXP B.V. 2012. All rights reserved. 16 of 21 AN11223 NXP Semiconductors Low Noise Fast Turn ON/OFF 2.4-2.5GHz WiFi LNA with BFU730LX Parameter Symbol Value Unit @2.4GHz ORL 17.6 dB @2.5GHz ORL 19.9 dB @2.4GHz ISLrev 23.2 dB @2.5GHz ISLrev 22.5 dB Input 1dB Gain Compression Point @2.4GHz Pi1dB -8.9 dBm @2.5GHz Pi1dB -8.9 dBm Output 1dB Gain Compression Point @2.4GHz PL1dB 7.2 dBm @2.5GHz PL1dB 7.2 dBm Input Third Order Intercept Point Two Tones: f1: 2450MHz, f2: 2451MHz, power: -30dBm @2.4GHz IIP3 2.5 dBm Output Third Order Intercept Point @2.4GHz Two Tones: f1: 2450MHz, f2: 2451MHz, power: -30dBm OIP3 19.5 dBm Stability ( 0- 15GHz) K >1 LNA Turn ON/OFF Time Ton 380 nS Toff 40 nS Output Return Loss Reverse Isolation [1] AN11223 Application note PCB and connector losses excluded. All information provided in this document is subject to legal disclaimers. Rev. 2 — 16 November 2012 © NXP B.V. 2012. All rights reserved. 17 of 21 AN11223 NXP Semiconductors Low Noise Fast Turn ON/OFF 2.4-2.5GHz WiFi LNA with BFU730LX 5. Legal information 5.1 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. 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. 5.2 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. 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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. 5.3 Licenses Purchase of NXP <xxx> components <License statement text> 5.4 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> 5.5 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. AN11223 Application note All information provided in this document is subject to legal disclaimers. Rev. 2 — 16 November 2012 © NXP B.V. 2012. All rights reserved. 18 of 21 AN11223 NXP Semiconductors Low Noise Fast Turn ON/OFF 2.4-2.5GHz WiFi LNA with BFU730LX 6. 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. BFU730LX Universal Demo Board 2.4-2.5GHz WiFi LNA EVB Demo Board.............................. 4 BFU730LX 2.4-2.5GHz WiFi LNA Simulation: Circuit (Capacitors GRM1555 & Inductors LQP15).............................................................. 5 BFU730LX 2.4-2.5GHz WiFi LNA Simulation: Gain and Match................................................. 6 BFU730LX 2.4-2.5GHz WiFi LNA Simulation: Noise Figure...................................................... 7 BFU730LX 2.4-2.5GHz WiFi LNA Simulation: Stability ............................................................. 8 BFU730LX Universal Demo Board: Schematic . 9 BFU730LX 2.4-2.5GHz WiFi LNA: Schematic .. 9 BFU730F 2.4-2.5GHz WiFi LNA: S-Parameter ........................................................................ 11 BFU730LX 2.4-2.5GHz WiFi LNA: IP3 ............ 12 BFU730LX 2.4-2.5GHz WiFi LNA: Stability .... 13 LNA Turn ON and Turn OFF time test setup... 14 BFU730LX 2.4-2.5GHz WiFi LNA: Turn ON time ........................................................................ 15 BFU730LX 2.4-2.5GHz WiFi LNA: Turn OFF time ................................................................. 16 AN11223 Application note All information provided in this document is subject to legal disclaimers. Rev. 2 — 16 November 2012 © NXP B.V. 2012. All rights reserved. 19 of 21 AN11223 NXP Semiconductors Low Noise Fast Turn ON/OFF 2.4-2.5GHz WiFi LNA with BFU730LX 7. List of tables Table 1. Table 2. BFU730LX 2.4-2.5GHz WiFi LNA Part List ..... 10 Typical results measured on the BFU730LX 2.42.5GHz WiFi LNA Evaluation Board ............... 16 AN11223 Application note All information provided in this document is subject to legal disclaimers. Rev. 2 — 16 November 2012 © NXP B.V. 2012. All rights reserved. 20 of 21 AN11223 NXP Semiconductors Low Noise Fast Turn ON/OFF 2.4-2.5GHz WiFi LNA with BFU730LX 8. Contents 1. 2. Introduction ......................................................... 3 Requirements and design of the 2.4-2.5GHz WiFi LNA .............................................................. 4 3. Design and Simulation ........................................ 5 3.1 BFU730LX 2.4-2.5GHz WiFi LNA Simulation..... 5 3.2 BFU730LX 2.4-2.5GHz WiFi LNA Simulation Result ................................................................. 6 3.2.1 Gain and Match in 2.4-2.5GHz Band ................. 6 3.2.2 Noise Figure in 2.4-2.5GHz Band ...................... 7 3.2.3 Stability .............................................................. 8 4. Application Board ............................................... 8 4.1 Application Circuit Schematic ............................. 9 4.2 Application Board Bill-Of-Material .................... 10 4.3 Typical Application Board Test Result.............. 11 4.3.1 S-Parameter – Gain and Match........................ 11 4.3.2 Linearity/IP3 ..................................................... 12 4.3.3 Stability ............................................................ 13 4.3.4 Noise Figure Measurement .............................. 13 4.3.5 LNA Turn ON/OFF Time .................................. 14 4.3.5.1 LNA Turn ON Time .......................................... 15 4.3.5.2 LNA Turn OFF Time ......................................... 16 4.3.6 Summary Of the Typical Evaluation Board Test Result ............................................................... 16 5. Legal information .............................................. 18 5.1 Definitions ........................................................ 18 5.2 Disclaimers....................................................... 18 5.3 Licenses ........................................................... 18 5.4 Patents ............................................................. 18 5.5 Trademarks ...................................................... 18 6. List of figures..................................................... 19 7. List of tables ...................................................... 20 8. Contents ............................................................. 21 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. 2012. 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 November 2012 Document identifier: AN11223