Application Note, Rev. 1.2, Oktober 2007 Application Note No. 126 BFP640F Low-Noise Silicon-Germanium Transistor as 5 -6 GHz Single-Stage Low Noise Amplifier (LNA), with reduced external component count and reduced gain at 2.4 GHz RF & Protection Devices Edition 2007-10-17 Published by Infineon Technologies AG 81726 München, Germany © Infineon Technologies AG 2010. 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. INFINEON TECHNOLOGIES HEREBY DISCLAIMS ANY AND ALL WARRANTIES AND LIABILITIES OF ANY KIND (INCLUDING WITHOUT LIMITATION WARRANTIES OF NON-INFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS OF ANY THIRD PARTY) WITH RESPECT TO ANY AND ALL INFORMATION GIVEN IN THIS APPLICATION NOTE. Information For further information on technology, delivery terms and conditions and prices please contact your nearest Infineon Technologies Office (www.infineon.com). Warnings Due to technical requirements components may contain dangerous substances. For information on the types in question please contact your nearest Infineon Technologies Office. Infineon Technologies Components may only be used in life-support devices or systems with the express written approval of Infineon Technologies, if a failure of such components can reasonably be expected to cause the failure of that life-support device or system, or to affect the safety or effectiveness of that device or system. 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. 126 Application Note No. 126 Revision History: 2007-10-17, Rev. 1.2 Previous Version: 2005-04-14, Rev. 1.1 Page Subjects (major changes since last revision) All Small changes in figure descriptions Application Note 3 Rev. 1.2, 2007-10-17 Application Note No. 126 BFP640F Low-Noise Silicon-Germanium Transistor as 5 -6 GHz Single-Stage 1 BFP640F Low-Noise Silicon-Germanium Transistor as 5 -6 GHz Single-Stage Low Noise Amplifier (LNA), with reduced external component count and reduced gain at 2.4 GHz Overview • • The Silicon-Germanium BFP640F in TSFP-4 package is shown in a modified 5 - 6 GHz LNA circuit derived from the BFP640 application shown in Applications Note AN082 (attached). This modified circuit is targeted for WLAN module manufacturers and reduces external component count to the absolute minimum. Note some performance is sacrificed to achieve reduced component count, most notably third-order intercept performance. Please also note, an attempt was made to reduce out-of-band gain, specifically to reduce gain at 2.4 GHz per customer request. In order to preserve input & output impedance match with reduced component count, a "trick" was used: DC blocking capacitors had their values increased such that they are used above their "self-resonant frequency" (SRF). C1 changes from 1.5 to 5.6 pF, C2 changes from 1.5 to 12 pF. Doing this makes these capacitors show some slight net inductive reactance in the 5 GHz frequency range, as opposed to these capacitors either appearing as a straight "short" or a capacitive reactance. The chip capacitors can be modeled as a series R-L-C with the capacitor's self-inductance being on the order of 0.5 nH. By using the chip's selfinductance, one can tailor the reactance of the chip capacitor by selecting the appropriate value of capacitance, and the R-L-C combination can be made to have resonance above the frequency of interest (normal case) or below the frequency of interest (done here in this "Trick"). Table 1 Comparison of Component Count for Original and Modified Circuits, for Single LNA Stage Component Type Number in Original Circuit Number in Modified Circuit (new) Comments Chip Capacitor 6 3 C3, C4, C6 eliminated Chip Resistor 3 3 Chip Inductor 3 1 • • L1, L3 eliminated 3 capacitors, 2 inductors have been eliminated, reducing external components from 12 pieces to 7 pieces. Please refer to schematic diagrams on page 4. Note gain at 2.4 GHz has been reduced from ≈ 15 dB to ≈ 8 dB (e.g. 7 dB gain reduction in 2.4 GHz range with this new, reduced parts count design). Applications • • • Wireless LAN (802.11a) Cordless Telephones (5.8 GHz) Other 5 -6 GHz systems Application Note 4 Rev. 1.2, 2007-10-17 Application Note No. 126 BFP640F Low-Noise Silicon-Germanium Transistor as 5 -6 GHz Single-Stage Summary Achieved ≅ 10 dB gain, 1.3 dB Noise Figure over the 4900 - 6000 MHz band, drawing 8.9 mA @ 3 V. Input 3rd Order Intercept = +8.7 dBm. Output P1dB = +6.9 dBm. Total external component count (L, C, R) has been reduced from 12 pieces to 7 pieces. Please note noise figure result does not extract PC board losses, if PCB loss were extracted, noise figure result would improve by approximately 0.2 - 0.3 dB (e.g. if loss is extracted, noise figure would be 1.1 to 1.3 dB). Cross Sectional Diagram of PC Board 7+,663$&,1*&5,7,&$/ 723/$<(5 LQFKPP ,17(51$/*5281'3/$1( LQFKPP" /$<(5)250(&+$1,&$/5,*,',7<2)3&%7+,&.1(66+(5(127 &5,7,&$/$6/21*$6727$/3&%7+,&.1(66'2(6127(;&((' ,1&+PP63(&,),&$7,21)25727$/3&%7+,&.1(66 ,1&+PPPP %27720/$<(5 $1B3&%YVG Figure 1 PCB - Cross Sectional Diagram Application Note 5 Rev. 1.2, 2007-10-17 Application Note No. 126 BFP640F Low-Noise Silicon-Germanium Transistor as 5 -6 GHz Single-Stage Summary of Data T = 25 °C, network analyzer source power = -30 dBm Table 2 Summary of Data Parameter Result Frequency Range Under 4.9 - 6 GHz DC Current 8.9 mA @ 3.0 V supply voltage (VCE = 2.7 V) Note power supply voltage is measured directly across PCB supply line and ground, to eliminate voltage drop across wire harness Gain 11.0 dB @ 4900 MHz 10.1 dB @ 5500 MHz 9.7 dB @ 6000 MHz Gain at 5150 MHz = 10.7 dB Noise Figure 1.3 dB @ 4900 MHz 1.4 dB @ 5500 MHz 1.5 dB @ 6000 MHz These values do NOT extract PCB losses, etc. resulting from FR4 board and passives used on PCB - these results are at input SMA connector Input P1dB -2.2 dBm @ 5500 MHz Output P1dB +6.9 dBm @ 5500 MHz rd Comments Input 3 Order Intercept +8.7 dBm @ 5150 MHz Output 3rd Order Intercept +19.4 dBm @ 5150 MHz Input Return Loss 9.3 dB @ 4900 MHz 11.6 dB @ 5500 MHz 14.0 dB @ 6000 MHz Output Return Loss 10.4 dB @ 4900 MHz 11.9 dB @ 5500 MHz 12.7 dB @ 6000 MHz Reverse Isolation 17.7 dB @ 4900 MHz 16.4 dB @ 5500 MHz 15.5 dB @ 6000 MHz Application Note 6 Figure 16 and Figure 17. IP3 could be improved by 6 to 10 dB by putting L1 and C3 back into the circuit. Rev. 1.2, 2007-10-17 Application Note No. 126 BFP640F Low-Noise Silicon-Germanium Transistor as 5 -6 GHz Single-Stage Schematic Diagram, Original Circuit 9 ,QGXFWRUVDUH0XUDWD/4306HULHVIRUPHUO\/43$ FDVHVL]H&DSDFLWRUVDQGUHVLVWRUVDUHFDVHVL]H 3&% 5HY& 3&%RDUG0DWHULDO 6WDQGDUG)5 5 . & & S) X) / Q+ - 5) ,1387 5 RKPV FF 9 - '&&RQQHFWRU , P$ & X) 5 RKPV & S) / Q+ 4 %)3)6L*H 7UDQVLVWRU & S) / Q+ & S) 1RWHEODFNUHFWDQJOHVDUHRKPWUDFHVRU WUDFNVRQWKH3ULQWHG&LUFXLW%RDUGWKHVH PDUNVDUH1276XUIDFH0RXQW&RPSRQHQWV - 5),1387 287387 ´;´PDUNLQGLFDWHVFRPSRQHQWVWR EHHOLPLQDWHGZLWKQHZFLUFXLW $1B6FKHPDWLFBRULJYVG Figure 2 Schematic Diagram Application Note 7 Rev. 1.2, 2007-10-17 Application Note No. 126 BFP640F Low-Noise Silicon-Germanium Transistor as 5 -6 GHz Single-Stage Schematic Diagram, NEW Circuit with Reduced Parts Count 9 ,QGXFWRUVDUH0XUDWD/4306HULHVIRUPHUO\/43$ FDVHVL]H&DSDFLWRUVDQGUHVLVWRUVDUHFDVHVL]H 3&% 5HY& 3&%RDUG0DWHULDO 6WDQGDUG)5 FF 9 - '&&RQQHFWRU , P$ 5 RKPV 5 RKPV 5 . - 5) ,1387 & S) / Q+ 4 %)3)6L*H 7UDQVLVWRU & S) & S) 1RWHEODFNUHFWDQJOHVDUHRKPWUDFHVRU WUDFNVRQWKH3ULQWHG&LUFXLW%RDUGWKHVH PDUNVDUH1276XUIDFH0RXQW&RPSRQHQWV - 5),1387 287387 $1B6FKHPDWLFBQHZYVG Figure 3 Schematic Diagram Application Note 8 Rev. 1.2, 2007-10-17 Application Note No. 126 BFP640F Low-Noise Silicon-Germanium Transistor as 5 -6 GHz Single-Stage Details on TSFP-4 Package (“Thin Small Flat Pack”). Dimensions in millimeters (mm). 0.2 ±0.05 3 1 1.2 ±0.05 0.2 ±0.05 4 0.55 ±0.04 2 0.2 ±0.05 10˚ MAX. 0.8 ±0.05 1.4 ±0.05 0.15 ±0.05 0.5 ±0.05 0.5 ±0.05 Figure 4 GPX01010 Package Details of TSFP-4 Recommended Soldering Footprint for TSFP-4 (dimensions in millimeters). Device package is to be oriented as shown in above drawing (e.g. orient long package dimension horizontally on this footprint). 0.9 0.45 0.35 0.5 0.5 HLGF1011 Figure 5 Package Footprint of TSFP-4 Application Note 9 Rev. 1.2, 2007-10-17 Application Note No. 126 BFP640F Low-Noise Silicon-Germanium Transistor as 5 -6 GHz Single-Stage Noise Figure, Plot, 4.5 GHz to 6.5 GHz. Center of Plot (x-axis) is 5.5 GHz. 5RKGH6FKZDU])6(. $SU 1RLVH)LJXUH (871DPH 0DQXIDFWXUHU 2SHUDWLQJ&RQGLWLRQV 2SHUDWRU1DPH 7HVW6SHFLILFDWLRQ &RPPHQW %)3)/RZ1RLVH$PSOLILHU*+]%DQG ,QILQHRQ7HFKQRORJLHV 9 9, P$7 & *HUDUG:HYHUV 5HGXFHG&RPSRQHQW&RXQW/:56'/1$3 2Q%)33&%5HY& 0DUFK $QDO\]HU 5)$WW 5HI/YO G% G%P 5%: 9%: 0+] +] 5DQJH G% 5HI/YODXWR 21 0HDVXUHPHQW QGVWDJHFRUU 21 0RGH 'LUHFW (15 +3$(15 1RLVH)LJXUHG% 0+] 0+]',9 0+] $1BSORWBQIYVG Figure 6 Noise Figure Application Note 10 Rev. 1.2, 2007-10-17 Application Note No. 126 BFP640F Low-Noise Silicon-Germanium Transistor as 5 -6 GHz Single-Stage Noise Figure, Tabular Data From Rhode & Schwarz FSEK3 + FSEM30 + System PreAmp Table 3 Noise Figure Frequency Noise Figure 4500 MHz 1.17 dB 4550 MHz 1.27 dB 4600 MHz 1.27 dB 4650 MHz 1.29 dB 4700 MHz 1.29 dB 4750 MHz 1.28 dB 4800 MHz 1.28 dB 4850 MHz 1.30 dB 4900 MHz 1.31 dB 4950 MHz 1.32 dB 5000 MHz 1.32 dB 5050 MHz 1.35 dB 5100 MHz 1.37 dB 5150 MHz 1.35 dB 5200 MHz 1.39 dB 5250 MHz 1.40 dB 5300 MHz 1.39 dB 5350 MHz 1.35 dB 5400 MHz 1.35 dB 5450 MHz 1.37 dB 5500 MHz 1.37 dB 5550 MHz 1.33 dB 5600 MHz 1.32 dB 5650 MHz 1.34 dB 5700 MHz 1.34 dB 5750 MHz 1.34 dB 5800 MHz 1.38 dB 5850 MHz 1.38 dB 5900 MHz 1.39 dB 5950 MHz 1.43 dB 6000 MHz 1.45 dB 6050 MHz 1.49 dB 6100 MHz 1.56 dB 6150 MHz 1.63 dB 6200 MHz 1.69 dB 6250 MHz 1.61 dB 6300 MHz 1.56 dB 6350 MHz 1.51 dB Application Note 11 Rev. 1.2, 2007-10-17 Application Note No. 126 BFP640F Low-Noise Silicon-Germanium Transistor as 5 -6 GHz Single-Stage Table 3 Noise Figure (cont’d) Frequency Noise Figure 6400 MHz 1.48 dB 6450 MHz 1.46 dB 6500 MHz 1.47 dB Application Note 12 Rev. 1.2, 2007-10-17 Application Note No. 126 BFP640F Low-Noise Silicon-Germanium Transistor as 5 -6 GHz Single-Stage Scanned Image of PC Board Figure 7 Image of PC Board Application Note 13 Rev. 1.2, 2007-10-17 Application Note No. 126 BFP640F Low-Noise Silicon-Germanium Transistor as 5 -6 GHz Single-Stage Scanned Image of PC Board, Close-In Shot Total PCB area used ≅ 40 mm² Figure 8 Image of PC Board, Close-In Shot Application Note 14 Rev. 1.2, 2007-10-17 Application Note No. 126 BFP640F Low-Noise Silicon-Germanium Transistor as 5 -6 GHz Single-Stage Stability Rohde and Schwarz ZVC Network Analyzer calculates and plots Stabilty Factor "K" in real time, from 5 MHz to 8 GHz. Note K>1 over entire range except at ≈ 260 MHz. Further work is needed to bring K>1 here. Suggest varying / tuning value of resistor R1 to improve K in 260 MHz range, or putting capacitor C6 back into the circuit, in order to improve "K" at low frequencies. &+ . 8 /,1 5H 8 5() 8 8 *+] * + ] *+] 8 *+] 8 *+] P8 0+] &$/ 2)6 8 &3/ 8 ),/ N 602 8 67$57 0+] 'DWH Figure 9 $35 *+] 6723 *+] $1BSORWBVWDELOLW\B.YVG Plot of K(f) Application Note 15 Rev. 1.2, 2007-10-17 Application Note No. 126 BFP640F Low-Noise Silicon-Germanium Transistor as 5 -6 GHz Single-Stage Gain Compression at 5500 MHz Amplifier is checked for 1 dB compression point at VCC = 3.0 V, IC = 8.9 mA (with VCE = 2.7 V). An Agilent power meter was used to ensure accurate power levels are measured (as opposed to using Vector Network Analyzer in "Power Sweep" mode). Input P1dB ≅ -2.2 dBm Output P1dB ≅ -2.2 dBm + (Gain - 1 dB) = -2.2 dBm + (10.1 - 1) dB = +6.9 dBm Table 4 Gain Compression Pin, dBm Pout, dBm Gain -11.0 -0.9 10.1 -10.0 +0.1 10.1 -9.0 +1.0 10.0 -8.0 +2.0 10.0 -7.0 +2.9 9.9 -6.0 +3.8 9.8 -5.0 +4.7 9.7 -4.0 +5.6 9.6 -3.0 +6.4 9.4 -2.0 +7.0 9.0 -1.0 +7.6 8.6 0.0 +8.1 8.1 Application Note 16 Rev. 1.2, 2007-10-17 Application Note No. 126 BFP640F Low-Noise Silicon-Germanium Transistor as 5 -6 GHz Single-Stage PLEASE NOTE - all plots are taken from Rohde And Schwarz ZVC Network Analyzer Input Return Loss, Log Mag 5 MHz to 8 GHz Sweep &+ 6 G% G% 0$* G% 5() G% G% *+] * + ] *+] G% *+] G% *+] G% *+] G% &$/ 2)6 G% &3/ ),/ N 602 G% 67$57 0+] 'DWH Figure 10 $35 *+] 6723 *+] $1BSORWBLQSXWBUHWXUQBORVVYVG Plot of Input Return Loss Application Note 17 Rev. 1.2, 2007-10-17 Application Note No. 126 BFP640F Low-Noise Silicon-Germanium Transistor as 5 -6 GHz Single-Stage Input Return Loss, Smith Chart Reference Plane = Input SMA Connector on PC Board 5 MHz to 8 GHz Sweep &+ 6 8 M *+] M *+] M *+] M *+] &$/ 2)6 &3/ ),/ N 602 67$57 0+] 'DWH Figure 11 $35 6723 *+] $1BVPLWKBLQSXWBUHWXUQBORVVYVG Smith Chart of Input Return Loss Application Note 18 Rev. 1.2, 2007-10-17 Application Note No. 126 BFP640F Low-Noise Silicon-Germanium Transistor as 5 -6 GHz Single-Stage Forward Gain 5 MHz to8 GHz Sweep &+ 6 G% G% 0$* G% 5() G% G% *+] * + ] *+] G% *+] G% *+] G% *+] &$/ G% 2)6 G% &3/ ),/ N 602 G% 67$57 0+] 'DWH Figure 12 $35 *+] 6723 *+] $1BSORWBIZBJDLQYVG Plot of Forward Gain Application Note 19 Rev. 1.2, 2007-10-17 Application Note No. 126 BFP640F Low-Noise Silicon-Germanium Transistor as 5 -6 GHz Single-Stage Reverse Isolation 5 MHz to 8 GHz Sweep &+ 6 G% G% 0$* G% 5() G% G% *+] * + ] *+] G% *+] G% *+] G% *+] G% &$/ 2)6 G% &3/ ),/ N 602 G% 67$57 0+] 'DWH Figure 13 $35 *+] 6723 *+] $1BSORWBUHYHUVHBLVRODWLRQYVG Plot of Reverse Isolation Application Note 20 Rev. 1.2, 2007-10-17 Application Note No. 126 BFP640F Low-Noise Silicon-Germanium Transistor as 5 -6 GHz Single-Stage Output Return Loss, Log Mag 5 MHz to 8 GHz Sweep &+ 6 G% G% 0$* G% 5() G% G% *+] * + ] *+] G% *+] G% *+] G% *+] &$/ G% 2)6 G% &3/ ),/ N 602 G% 67$57 0+] 'DWH Figure 14 $35 *+] 6723 *+] $1BSORWBRXWSXWBUHWXUQBORVVYVG Plot of Output Return Loss Application Note 21 Rev. 1.2, 2007-10-17 Application Note No. 126 BFP640F Low-Noise Silicon-Germanium Transistor as 5 -6 GHz Single-Stage Output Return Loss, Smith Chart Reference Plane = Output SMA Connector on PC Board 5 MHz to 8 GHz Sweep &+ 6 8 M *+] M *+] M *+] M *+] &$/ 2)6 &3/ ),/ N 602 67$57 0+] 'DWH Figure 15 $35 6723 *+] $1BVPLWKBRXWSXWBUHWXUQBORVVYVG Smith Chart of Output Return Loss Application Note 22 Rev. 1.2, 2007-10-17 Application Note No. 126 BFP640F Low-Noise Silicon-Germanium Transistor as 5 -6 GHz Single-Stage Input Stimulus for Amplifier Two-Tone Test f1 = 5150 MHz, f2 = 5151 MHz, -23 dBm each tone. $1BSORWBWZRBWRQHBLQSXWYVG Figure 16 Tow-Tone Test, Input Stimulus Application Note 23 Rev. 1.2, 2007-10-17 Application Note No. 126 BFP640F Low-Noise Silicon-Germanium Transistor as 5 -6 GHz Single-Stage LNA Response to Two-Tone Test Input IP3 = -23 + (63.3/2) = +8.7 dBm Output IP3 = +8.7 dBm + 10.7 dB gain = + 19.4 dBm $1BSORWBWZRBWRQHBUHVSRQVHYVG Figure 17 Tow-Tone Test, LNA Response Application Note 24 Rev. 1.2, 2007-10-17