A p pl i c at i on N ot e , R ev . 1 . 2, A p ri l 2 00 8 A p p li c a t i o n N o t e N o . 1 5 5 B F P 4 20 a s a L o w - C o s t L N A fo r G l ob a l P o s i t i o n i n g L 1 B a n d ( 1 5 7 5 .4 2 M H z ) R F & P r o t e c ti o n D e v i c e s Edition 2008-04-04 Published by Infineon Technologies AG 81726 München, Germany © Infineon Technologies AG 2009. All Rights Reserved. LEGAL DISCLAIMER THE INFORMATION GIVEN IN THIS APPLICATION NOTE IS GIVEN AS A HINT FOR THE IMPLEMENTATION OF THE INFINEON TECHNOLOGIES COMPONENT ONLY AND SHALL NOT BE REGARDED AS ANY DESCRIPTION OR WARRANTY OF A CERTAIN FUNCTIONALITY, CONDITION OR QUALITY OF THE INFINEON TECHNOLOGIES COMPONENT. THE RECIPIENT OF THIS APPLICATION NOTE MUST VERIFY ANY FUNCTION DESCRIBED HEREIN IN THE REAL APPLICATION. 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Life support devices or systems are intended to be implanted in the human body, or to support and/or maintain and sustain and/or protect human life. If they fail, it is reasonable to assume that the health of the user or other persons may be endangered. Application Note No. 155 Application Note No. 155 Revision History: 2008-04-04, Rev. 1.2 Previous Version: 2001-01-10, Rev. 1.1 Page Subjects (major changes since last revision) All Small changes in figure descriptions Application Note 3 Rev. 1.2, 2008-04-04 Application Note No. 155 BFP420 as a Low-Cost LNA for Global Positioning L1 Band (1575.42 MHz) 1 BFP420 as a Low-Cost LNA for Global Positioning L1 Band (1575.42 MHz) Overview • • • Demo of BFP420 LNA for GPS L1 frequency. PC board used is BFP620 V 3.0 with sawed-off input. Note this PCB has inductive emitter degeneration (short microstrip tracks between device emitter leads and ground plane) which is useful for 1) improving stability 2) input / output match and 3) improving amplifier compression point. Note approximately 1 to 2 dB additional gain could be had if best possible emitter grounding were used (e.g. no degeneration) were used. Test Conditions: VCC = 2.75 V, VCE = 2.5 V, total current = 5 mA, T = 25 °C, network analyzer source power = -30 dBm Amplifier is unconditionally stable (e.g. K > 1 and B1 > 0 over 100 MHz - 6 GHz range). Summary of Data Table 1 Summary of Data Parameter Result / Value Frequency Range 1575.42 MHz (GPS L1 frequency) DC Current 5.0 mA DC Voltage, VCC 2.75 V Collector-Emitter Voltage, VCE 2.5 V Input P1dB ≈ -15.9 dBm @ 1575.42 MHz Output P1dB ≈ -2.7 dBm @ 1575.42 MHz rd Input 3 Order Intercept rd +4.3 dBm @ 1575.42 MHz Output 3 Order Intercept +18.5 dBm @ 1575.42 MHz Noise Figure +1.3 dBm @ 1575.42 MHz Gain +14.2 dBm @ 1575.42 MHz Input return loss +10.8 dBm @ 1575.42 MHz Output return loss +11.1 dBm @ 1575.42 MHz Reverse isolation +23.9 dBm @ 1575.42 MHz Application Note 4 Rev. 1.2, 2008-04-04 Application Note No. 155 BFP420 as a Low-Cost LNA for Global Positioning L1 Band (1575.42 MHz) Schematic Diagram 9FF 9 - '&&RQQHFWRU , P$ 5 RKPV 5 . & X) & S) / Q+ - 5),1387 & X) 5 RKPV 4 %)3 7UDQVLVWRU & S) / Q+ & S) & S) / Q+ - 5)287387 3&%RDUG %)39 ,QSXW VDZHGRII 6XEVWUDWHKHLJKW PLOPP 0DWHULDO VWDQGDUG)5 ,QGXFWLYH(PLWWHU'HJHQHUDWLRQ 7ZRPLFURVWULSWUDFNV: PLOPP/ PLOPP $1B6FKHPDWLFYVG Figure 1 Schematic Diagram Application Note 5 Rev. 1.2, 2008-04-04 Application Note No. 155 BFP420 as a Low-Cost LNA for Global Positioning L1 Band (1575.42 MHz) Bill of Material Table 2 Bill of Material Reference Designator Value Manufacturer Case Size Function C1 15 pF Various 0402 DC blocking, input C2 1.5 pF Various 0402 DC block, output. Influences input match since S12 ≠ 0. C3 0.1 µF Various 0402 Low frequency ground at base (Input 3rd Order Intercept improvement). C4 15 pF Various 0402 RF bypass / RF block C5 15 pF Various 0402 RF bypass / RF block C6 0.1 µF Various 0402 Bypass / block, some IP3 improvement. L1 10 nH Murata LQG10A low cost 0402 inductor RF choke to DC bias on base, input matching. L2 6.2 nH Murata LQG10A low cost 0402 inductor Output RF match, DC feed to collector. L3 3.9 nH Murata LQG10A low cost 0402 inductor Output match. R1 10 Ω Various 0402 Improves stability, output matching. R2 30 kΩ Various 0402 DC bias for base. R3 39 Ω Various 0402 Drop supply voltage. Q1 - Infineon Technologies SOT343 BFP420 Si Bipolar, fT = 25 GHz J1, J2 - Johnson 142-0701-841 - RF input / output connectors J3 - AMP 5 pin header MTA100 series 640456-5 (standard pin plating) or 641215-5 (gold plated pins) - DC connector Application Note Pins 1, 5 = ground Pin 3 = VCC Pins 2, 4 = no connection 6 Rev. 1.2, 2008-04-04 Application Note No. 155 BFP420 as a Low-Cost LNA for Global Positioning L1 Band (1575.42 MHz) Noise Figure, Plot. Center of Plot (x-axis) is 1575.42 MHz. 5RKGHDQG6FKZDU])6(.9 -DQ %)3VHWXSDV*36//1$ (871DPH 0DQXIDFWXUHU 2SHUDWLQJ&RQGLWLRQV 2SHUDWRU1DPH 7HVW6SHFLILFDWLRQ &RPPHQW 3&% %)39 ,QILQHRQ 9 9, P$9FH YROWV *HUDUG:HYHUV 'DYLG9HVVDO $QDO\]HU 5)$WW 5HI/YO G% G%P 5%: 0+] 9%: +] 5DQJH G% 5HI/YODXWR 21 0RGH 'LUHFW (15 +3$(15 0HDVXUHPHQW QGVWDJHFRUU 21 1RLVH)LJXUHG% 0+] 0+]',9 0+] $1BSORWBQIYVG Figure 2 Noise Figure Application Note 7 Rev. 1.2, 2008-04-04 Application Note No. 155 BFP420 as a Low-Cost LNA for Global Positioning L1 Band (1575.42 MHz) Noise Figure, Tabular Data Table 3 Noise Figure Frequency Noise Figure 1525.42 MHz 1.28 dB 1530.42 MHz 1.29 dB 1535.42 MHz 1.27 dB 1540.42 MHz 1.30 dB 1545.42 MHz 1.29 dB 1550.42 MHz 1.29 dB 1555.42 MHz 1.29 dB 1560.42 MHz 1.28 dB 1565.42 MHz 1.29 dB 1570.42 MHz 1.28 dB 1575.42 MHz 1.30 dB 1580.42 MHz 1.28 dB 1585.42 MHz 1.28 dB 1590.42 MHz 1.29 dB 1595.42 MHz 1.28 dB 1600.42 MHz 1.28 dB 1605.42 MHz 1.28 dB 1610.42 MHz 1.29 dB 1615.42 MHz 1.30 dB 1620.42 MHz 1.27 dB 1625.42 MHz 1.29 dB Application Note 8 Rev. 1.2, 2008-04-04 Application Note No. 155 BFP420 as a Low-Cost LNA for Global Positioning L1 Band (1575.42 MHz) Stability Factors K and B1 For unconditional stability, K > 1 and B1 > 0. (For plot, actual measured LNA s-parameters are imported into the Ansoft Serenade design environment; the software calculates and plots K and B1). Note red trace is K, blue trace is B1. $QVRIW&RUSRUDWLRQ±+DUPRQLFDY $FWXDO0HDVXUHG.DQG%9DOXHVIURPPHDVXUHG$PSOLILHU6SDUDPHWHUILOH '?*ZHYHUV?&DOFXODWH.B%B,PSRUW6SDU?&DOFXODWH.B%B,PSRUWVSDUFNW $1BSORWBVWDELOLW\B.B%YVG Figure 3 Plot of K(f) and B1(f) Application Note 9 Rev. 1.2, 2008-04-04 Application Note No. 155 BFP420 as a Low-Cost LNA for Global Positioning L1 Band (1575.42 MHz) LNA Gain Compression at 1575.42 MHz Input P1dB ≅ -15.9 dBm Output P1dB ≅ -2.7 dBm Table 4 Gain Compression at 1575.42 MHz Input Power, dBm Output Power, dBm Gain, dB -28 -13.8 14.2 -26 -11.8 14.2 -24 -9.9 14.1 -22 -7.9 14.1 -20 -6.1 13.9 -18 -4.2 13.8 -16 -2.7 13.3 -14 -1.5 12.5 -12 -0.5 11.5 Scanned Image of PCB, top of board Figure 4 Image of PC Board Input Return Loss, Log Mag Application Note 10 Rev. 1.2, 2008-04-04 Application Note No. 155 BFP420 as a Low-Cost LNA for Global Positioning L1 Band (1575.42 MHz) &+ 6 ORJ0$* G% 5()G% -DQ BG% 0+] 35P &RU 'HO 5()(5(1&(/,1(326,7,21 'LY &(17(50+] 63$10+] $1BSORWBLQSXWBUHWXUQBORVVYVG Figure 5 Plot of Input Return Loss Application Note 11 Rev. 1.2, 2008-04-04 Application Note No. 155 BFP420 as a Low-Cost LNA for Global Positioning L1 Band (1575.42 MHz) Input Return Loss, Smith Chart Reference Plane = PCB RF Output Connector &+ 6 8)6 B -DQ S) 0+] 35P &RU 'HO &(17(50+] 63$10+] $1BVPLWKBLQSXWBUHWXUQBORVVYVG Figure 6 Smith Chart of Input Return Loss Application Note 12 Rev. 1.2, 2008-04-04 Application Note No. 155 BFP420 as a Low-Cost LNA for Global Positioning L1 Band (1575.42 MHz) Forward Gain &+ 6 ORJ0$* G% 5()G% -DQ BG% 0+] 35P &RU 'HO $YJ 6PR &(17(50+] 63$10+] $1BSORWBIZBJDLQYVG Figure 7 Plot of Forward Gain Application Note 13 Rev. 1.2, 2008-04-04 Application Note No. 155 BFP420 as a Low-Cost LNA for Global Positioning L1 Band (1575.42 MHz) Reverse Isolation &+ 6 ORJ0$* G% 5()G% -DQ BG% 0+] 35P &RU 'HO $YJ 6PR 6&$/( G%GLY &(17(50+] 63$10+] $1BSORWBUHYHUVHBLVRODWLRQYVG Figure 8 Plot of Reverse Isolation Application Note 14 Rev. 1.2, 2008-04-04 Application Note No. 155 BFP420 as a Low-Cost LNA for Global Positioning L1 Band (1575.42 MHz) Output Return Loss, Log Mag &+ 6 ORJ0$* G% 5()G% -DQ BG% 0+] 35P &RU 'HO $YJ 6PR &(17(50+] 63$10+] $1BSORWBRXWSXWBUHWXUQBORVVYVG Figure 9 Plot of Output Return Loss Application Note 15 Rev. 1.2, 2008-04-04 Application Note No. 155 BFP420 as a Low-Cost LNA for Global Positioning L1 Band (1575.42 MHz) Output Return Loss, Smith Chart Reference Plane = PCB RF Output Connector &+ 6 8)6 B -DQ S) 0+] 35P &RU 'HO $YJ 6PR &(17(50+] 63$10+] $1BVPLWKBRXWSXWBUHWXUQBORVVYVG Figure 10 Smith Chart of Output Return Loss Application Note 16 Rev. 1.2, 2008-04-04 Application Note No. 155 BFP420 as a Low-Cost LNA for Global Positioning L1 Band (1575.42 MHz) Two-Tone Test Output Response of Amplifier to Two-Tone 3rd Order Intercept Test. Two Tones: f1 = 1574.920 MHz, f2 = 1575.920 MHz, -25 dBm each tone, tone spacing = 1 MHz. Input IP3 = -25 + (58.2 / 2) = +4.3 dBm $1BSORWBWZRBWRQHBUHVSRQVHYVG Figure 11 Plot of Tow-Tone Test, LNA response Application Note 17 Rev. 1.2, 2008-04-04