Application Note No. 127

Application Note, Rev. 1.2, November 2007 Application Note No. 127 1.8 V Ultra Low Cost LNA for GPS, PHS, UMTS and 2.4 GHz ISM using BFP640F RF & Protection Devices

Edition 2007-11-28 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. 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. 127 Revision History: 2007-11-28, Rev. 1.2 Previous Version: 2005-05-04, Rev. 1.1 Page Subjects (major changes since last revision) All Small changes in figure descriptions Application Note 3 Rev. 1.2, 2007-11-28

1 1.8 V Ultra Low Cost LNA for GPS, PHS, UMTS and 2.4 GHz ISM using BFP640F Applications Global Positioning System (GPS) L1 frequency 1575.42 MHz 1900 MHz PHS 2.1 GHz UMTS 2.33 GHz Satellite Radio SDARS 2.4 GHz ISM Band, etc. Overview Silicon-Germanium HBT BFP640F transistor in TSFP-4 package is shown in modified LNA circuit suitable for 1575 MHz GPS, 1900 MHz PHS & 2.4 GHz ISM band applications, operating from a 1.8 V power supply. This circuit reduces external component count to the absolute minimum. Some performance is sacrificed to achieve reduced component count, e.g. third-order intercept performance. To maintain input impedance match with reduced component count, "trick" was employed: DC blocking capacitor at input (C1) had value increased such that it is used above "self-resonant frequency" (SRF). Doing so makes capacitor show slight net inductive reactance +jx above UHF, rather than capacitor appearing as a straight "short" or a capacitive reactance (-jx). Chip capacitors can be modeled as a series R-L-C with capacitor's self-inductance being on the order of 0.5 nh. By using chip's self-inductance, one can tailor reactance of chip capacitor by selecting the appropriate value of capacitance, and the R-L-C combination can be made to have resonance above frequency of interest (normal case) or below frequency of interest (done here in this "Trick"). Features No Chip Inductors / Chip Coils used in this circuit Circuit uses only 3 Capacitors, 3 Resistors for low Component Count and Low Cost Table 1 Summary Frequency MHz Gain db Noise Figure (NF)* db IIP 3 dbm 1575 15.2 0.9-3.4 1900 13.8 1.0-1.9 2140 13.0 1.0-2.7 2450 12.0 1.1 0.0 * Note that PCB loss is not extracted. If PCB loss were extracted, NF would be 0.1 to 0.2 db lower. Application Note 4 Rev. 1.2, 2007-11-28

Cross Sectional Diagram of PC Board Figure 1 PCB - Cross Sectional Diagram Schematic Diagram, with reduced Parts Count Note 0402 case size passives are used. Figure 2 Schematic Diagram Application Note 5 Rev. 1.2, 2007-11-28

Summary of Data T = 25 C, network analyzer source power -30 dbm Table 2 Summary of Data Parameter Result Comments Frequency Range 1.5 - >3 GHz Covers GPD, PHS, UMTS, SDARS, ISM DC Current (V CC = 1.8 V, V CE = 0.8 V) Gain Noise Figure Input P 1dB Output P 1dB Input 3 rd Order Intercept Output 3 rd Order Intercept Input Return Loss Output Return Loss Reverse Isolation 7.9 ma Power supply voltage measured directly across PCB supply line & ground, to eliminate voltage drop. 15.2 db @ 1575 MHz 13.8 db @ 1900 MHz 13.0 db @ 2140 MHz 12.0 db @ 2440 MHz 0.9 db @ 1575 MHz 1.0dB @ 1900MHz 1.0dB @ 2140MHz 1.1dB @ 2440MHz -0.1 dbm @ 1575 MHz -0.2 dbm @ 2440 MH -0.1 dbm @ 1575 MHz +0.2 dbm @ 2440 MH -3.4 db @ 1575 MHz -1.9 db @ 1900 MHz -2.7 db @ 2140 MHz 0.0dB @ 2440MHz +11.8 db @ 1575 MHz +11.9 db @ 1900 MHz +10.3 db @ 2140 MHz +12.0 db @ 2440 MHz 9.4 db @ 1575 MHz 10.5 db @ 1900 MHz 11.1 db @ 2140 MHz 11.9 db @ 2440 MHz 9.3 db @ 1575 MHz 10.3 db @ 1900 MHz 10.9 db @ 2140 MHz 11.7 db @ 2440 MHz 24.6 db @ 1575 MHz 23.1 db @ 1900 MHz 22.2 db @ 2140 MHz 21.2 db @ 2440 MHz < 1 db NF at GPS band PCB loss not extracted, these results are at input SMA connector IP 3 could be improved 6 to 10 db by adding in LF Trap at Input, add in 1 inductor, 1 capacitor Application Note 6 Rev. 1.2, 2007-11-28

Details on TSFP-4 Package ( Thin Small Flat Pack. ). Dimensions in millimeters (mm). 1.4 ±0.05 0.2 ±0.05 4 3 1 2 0.2 ±0.05 0.5 ±0.05 0.5 ±0.05 1.2 ±0.05 0.2 ±0.05 0.55 ±0.04 0.15 ±0.05 10 MAX. 0.8 ±0.05 GPX01010 Figure 3 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). 0.35 0.45 0.9 0.5 0.5 HLGF1011 Figure 4 Package Footprint of TSFP-4 Application Note 7 Rev. 1.2, 2007-11-28

Noise Figure, Plot, 1.5 GHz to 3.0 GHz. Center of Plot (x-axis) is 2.25 GHz. Figure 5 Noise Figure Application Note 8 Rev. 1.2, 2007-11-28

Noise Figure, Tabular Data From Rhode & Schwarz FSEK3 + FSEM30 + System PreAmp Table 3 Noise Figure Frequency Noise Figure 1500 MHz 0.91 db 1525 MHz 0.88 db 1550 MHz 0.90 db 1575 MHz 0.91 db 1600 MHz 0.89 db 1625 MHz 0.89 db 1650 MHz 0.90 db 1675 MHz 0.88 db 1700 MHz 0.90 db 1725 MHz 0.91 db 1750 MHz 0.97 db 1775 MHz 0.96 db 1800 MHz 0.97 db 1825 MHz 0.96 db 1850 MHz 0.98 db 1875 MHz 0.99 db 1900 MHz 0.99 db 1925 MHz 1.02 db 1950 MHz 1.03 db 1975 MHz 1.04 db 2000 MHz 1.05 db 2025 MHz 1.02 db 2050 MHz 1.04 db 2075 MHz 1.04 db 2100 MHz 1.04 db 2125 MHz 1.03 db 2150 MHz 1.05 db 2175 MHz 1.03 db 2200 MHz 1.03 db 2225 MHz 1.08 db 2250 MHz 1.06 db 2275 MHz 1.06 db 2300 MHz 1.07 db 2325 MHz 1.04 db 2350 MHz 1.05 db 2375 MHz 1.06 db 2400 MHz 1.04 db 2425 MHz 1.05 db Application Note 9 Rev. 1.2, 2007-11-28

Table 3 Noise Figure (cont d) Frequency Noise Figure 2450 MHz 1.08 db 2475 MHz 1.09 db 2500 MHz 1.05 db 2525 MHz 1.10 db 2550 MHz 1.07 db 2575 MHz 1.07 db 2600 MHz 1.07 db 2625 MHz 1.07 db 2650 MHz 1.12 db 2675 MHz 1.09 db 2700 MHz 1.09 db 2725 MHz 1.08 db 2750 MHz 1.08 db 2775 MHz 1.09 db 2800 MHz 1.11 db 2825 MHz 1.12 db 2850 MHz 1.12 db 2875 MHz 1.12 db 2900 MHz 1.09 db 2925 MHz 1.09 db 2950 MHz 1.11 db 2975 MHz 1.11 db 3000 MHz 1.10 db Application Note 10 Rev. 1.2, 2007-11-28

Scanned Image of PC Board Figure 6 Image of PC Board Application Note 11 Rev. 1.2, 2007-11-28

Scanned Image of PC Board, Close-In Shot Total PCB area used 35 mm² Figure 7 Image of PC Board, Close-In Shot Application Note 12 Rev. 1.2, 2007-11-28

Stability Rohde and Schwarz ZVC Network Analyzer calculates and plots Stability Factor "K" in real time, from 5 MHz to 8 GHz. Note K>1 from 870 MHz to 8 GHz; however K<1 in VHF - UHF range (e.g. 100-800 MHz). Further work needed to bring K>1 here. May need to add 1-2 components to achieve this. Figure 8 Plot of K(f) Application Note 13 Rev. 1.2, 2007-11-28

Gain Compression at 1575 MHz and 2440 MHz Amplifier is checked for 1 db compression point at V CC = 1.8 V, I C = 7.9 ma (with V CE = 0.8 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). 1575 MHz (GPS) Input P 1dB -14.3 dbm Output P 1dB -14.3 dbm + (Gain - 1 db) = -14.3 dbm + (15.2-1) db = -0.1 dbm Table 4 Gain Compression at 1575 MHz P in, dbm P out, dbm Gain -20.0-4.8 15.2-19.0-3.8 15.2-18.0-3.0 15.0-17.0-2.1 14.9-16.0-1.3 14.7-15.0-0.6 14.4-14.0 0.0 14.0-13.0 +0.5 13.5-12.0 +1.0 13.0-11.0 +1.4 12.4-10.0 +1.8 11.8 2440 MHz (2.4 GHz ISM Band) Input P 1dB -10.8 dbm Output P 1dB -10.8 dbm + (Gain - 1 db) = -10.8 dbm + (12.0-1) db = +0.2 dbm Table 5 Gain Compression at 2440 MHz P in, dbm P out, dbm Gain -20.0-8.0 12.0-19.0-7.0 12.0-18.0-6.1 11.9-17.0-5.2 11.8-16.0-4.2 11.8-15.0-3.2 11.8-14.0-2.3 11.7-13.0-1.4 11.6-12.0-0.6 11.4-11.0 +0.1 11.1-10.0 +0.8 10.8 Application Note 14 Rev. 1.2, 2007-11-28

PLEASE NOTE - all plots are taken from Rohde And Schwarz ZVC Network Analyzer, with T = 25 C, source power -30 dbm. Input Return Loss, Log Mag 5 MHz to 8 GHz Sweep Figure 9 Plot of Input Return Loss Application Note 15 Rev. 1.2, 2007-11-28

Input Return Loss, Smith Chart Reference Plane = Input SMA Connector on PC Board 5 MHz to 8 GHz Sweep Figure 10 Smith Chart of Input Return Loss Application Note 16 Rev. 1.2, 2007-11-28

Forward Gain 5 MHz to8 GHz Sweep Figure 11 Plot of Forward Gain Application Note 17 Rev. 1.2, 2007-11-28

Reverse Isolation 5 MHz to 8 GHz Sweep Figure 12 Plot of Reverse Isolation Application Note 18 Rev. 1.2, 2007-11-28

Output Return Loss, Log Mag 5 MHz to 8 GHz Sweep Figure 13 Plot of Output Return Loss Application Note 19 Rev. 1.2, 2007-11-28

Output Return Loss, Smith Chart Reference Plane = Output SMA Connector on PC Board 5 MHz to 8 GHz Sweep Figure 14 Smith Chart of Output Return Loss Application Note 20 Rev. 1.2, 2007-11-28

Two-Tone Test, GPS (1575 MHz) Input Stimulus for Amplifier Two-Tone Test. f 1 = 1574 MHz, f 2 = 1575 MHz, -25 dbm each tone. Figure 15 Tow-Tone Test, Input Stimulus @ 1575 MHz Application Note 21 Rev. 1.2, 2007-11-28

Two-Tone Test, GPS (1575 MHz) LNA Response to Two-Tone Test. Input IP 3 = -25 + (43.3 / 2) = -3.4 dbm. Output IP 3 = -3.4 dbm + 15.2 db gain = +11.9 dbm. Figure 16 Tow-Tone Test, LNA Response @ 1575 MHz Application Note 22 Rev. 1.2, 2007-11-28

Two-Tone Test, PHS (1900 MHz) Input Stimulus for Amplifier Two-Tone Test. f 1 = 1900 MHz, f 2 = 1901 MHz, -25 dbm each tone. Figure 17 Tow-Tone Test, Input Stimulus @ 1900 MHz Application Note 23 Rev. 1.2, 2007-11-28

Two-Tone Test, PHS (1900 MHz) LNA Response to Two-Tone Test. Input IP 3 = -25 + (46.2 / 2) = -1.9 dbm. Output IP 3 = -1.9 dbm + 13.8 db gain = +11.9 dbm. Figure 18 Tow-Tone Test, LNA Response @ 1900 MHz Application Note 24 Rev. 1.2, 2007-11-28

Two-Tone Test, UMTS (2.1 GHz Band) Input Stimulus for Amplifier Two-Tone Test. f 1 = 2140 MHz, f 2 = 2141 MHz, -25 dbm each tone. Figure 19 Tow-Tone Test, Input Stimulus @ 2.1 GHz Application Note 25 Rev. 1.2, 2007-11-28

Two-Tone Test, UMTS (2.1 GHz Band) LNA Response to Two-Tone Test. Input IP 3 = -25 + (44.6 / 2) = -2.7 dbm. Output IP 3 = -2.7 dbm + 13.0 db gain = +10.3 dbm. Figure 20 Tow-Tone Test, LNA Response @ 2.1 GHz Application Note 26 Rev. 1.2, 2007-11-28

Two-Tone Test, 2.4 GHz IMS Band Input Stimulus for Amplifier Two-Tone Test. f 1 = 2440 MHz, f 2 = 2441 MHz, -25 dbm each tone. Figure 21 Tow-Tone Test, Input Stimulus @ 2.4 GHz Application Note 27 Rev. 1.2, 2007-11-28

Two-Tone Test, 2.4 GHz ISM Band LNA Response to Two-Tone Test. Input IP 3 = -25 + (50.0 / 2) = 0.0 dbm. Output IP 3 = 0.0 dbm + 12.0 db gain = +12.0 dbm. Figure 22 Tow-Tone Test, LNA Response @ 2.4 GHz Application Note 28 Rev. 1.2, 2007-11-28