 |
|
| If you can't view the Datasheet, Please click here to try to view without PDF Reader . |
|
|
|
| If you can't view the Datasheet, Please click here to try to view without PDF Reader . |
|
|
| Datasheet File OCR Text: |
| AN1352 APPLICATION NOTE A LNA OPTIMIZED FOR HIGH IP3out AT 1.9GHz USING THE NPN Si START420 TRANSISTOR F. Caramagno - G. Privitera Data at 1.9GHz (3V, 20mA) Gain = 18dB, IP3out = 23dBm, NF = 1.9dB, RLin/out > 13dB 1. INTRODUCTION. START420 is a product of the START Family (ST Advanced Radio frequency Transistor). It is a high performance silicon bipolar transistor housed in the ultra miniature 4-lead SC-70 (SOT-343) surface mount plastic package. The amplifier is designed for use with 30mils thickness FR-4 printed circuit board material. The amplifier application circuit has been optimized to achieve a good compromise among IP3, noise figure and return loss at 1.9GHz, with Vce=2V and Ic=20mA. The amplifier has 18dB of Gain, 1.9dB of Noise Figure a Input and Output Return Loss >13dB and an output IP3 of +23dBm (1.9GHz, 3V, 20mA). 2. LNA DESIGN. Figure 1: Schematic Design J3 Vcc +3V 2 1 + R3 27 C8 1 R1 13K C2 10n C5 100p R2 18 C6 10n START420 C4 10n TrL2 Tr1 TrL1 TrL5 TrL6 L1 1.5n TrL4 C7 10p J2 RF_out J1 RF_in C3 100p C1 3.9p TrL3 June 2001 (Rev. 1) 1/6 AN1352 - APPLICATION NOTE This amplifier is realized with a microstrip line as matching elements and a small number of surfacemount components. A single pin (Vcc=3V) for voltage supply is used. A 1F bypass capacitor to filter the supply at the common Vcc node is also used. The transistor's base is connected to the power supply through a choke inductor (microstrip line TrL3) and the transistor's collector is connected to the voltage supply through a choke inductor (microstrip line TrL4). The collector's voltage is 2V. The input matching is realized with both a chip-capacitor (C1) and a 60ohm series transmission line of 15 electrical length (TrL1). The output matching is realized with both a chip-inductor (L1) and a 60ohm series transmission line of 16 electrical length (TrL2). Resistor (R2) is used to improve RF circuit stability. Figure 2: Demoboard Layout 21mm 40mm Table 1: Bill of Materials Component Value R1 R2 R3 C1 C2 C3 C4 C5 C6 C7 C8 L1 Tr1 TrL1 TrL2 TrL3 TrL4 TrL5 TrL6 J1 J2 J3 Substrate 2/6 Unit pF nF pF nF pF nF pF F nH Size 0603 0603 0603 0603 0603 0603 0603 0603 0603 0603 0603 0603 SOT-343 Comment 13 18 27 3.9 10 100 10 100 10 10 1 1.5 FR4 Start420 Inputmatch, w=1mm Outputmatch, w=1mm Dc-bias, w=0.3 Dc-bias, w=0.3 emitter-microstrip-line, w=0.7mm emitter-microstrip-line, w=0.7mm RF Connector; sma-f RF Connector; sma-f DC Connector h= 0.03 inch; Er=4.5 AN1352 - APPLICATION NOTE 3. LNA PERFORMANCE. The high intercept point START420 amplifier is biased at Vce=2V and Ic=20mA. The measured gain and noise figure is shown in figures 3 and 4. The optimum amplifier noise figure is 1.9dB and the associated gain between 1800MHz and 1900MHz is about 18dB. Measured input and output return loss are shown in figures 5 and 6. The Input Return Loss is about 18dB from 1800MHz through 1900MHz. Figure 3: Power Gain vs. Frequency dB 40 30 20 10 0 750 1000 1250 1500 1750 MHz 2000 2250 2500 Figure 4: Noise Figure vs. Frequency dB 3 2 1 750 1000 1250 MHz 1500 1750 2000 3/6 AN1352 - APPLICATION NOTE Figure 5: Input Return Loss vs. Frequency dB 0 -10 -20 -30 -40 750 1000 1250 1500 1750 2000 2250 2500 MHz Figure 6: Output Return Loss vs. Frequency dB 0 -10 -20 -30 -40 750 1000 1250 1500 1750 MHz 2000 2250 2500 Figure 7: In-band Third Order Intermodulation Product Distorsion 0 Output Power (dBm) 3 f -46 2f1- f2 f1 f2 2f2- f1 frequency 4/6 AN1352 - APPLICATION NOTE Figure 7 is a partial representation of the LNA output spectrum. f1=1900MHz and f2 =1901MHz are equal amplitude input test tones. For this LNA we use -18dBm input power in order to reach 0dBm of output power for each test tones. Other signals besides f1 and f2 are generated as a result of non-linear device behavior. The Output IP3 is calculated as follows: IM3 IP3out = ------------- + Pout 2 where IM3 (please refer figure 7) is the difference between one of two equal amplitude test tones present at the amplifier output, and the level of the highest 3rd -order distortion product. The IM3 measured is 46dB. So we have: IM3 46 IP 3out = ------------- + Pout = ----- + 0 = 23dB m 2 2 5/6 AN1352 - APPLICATION NOTE Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specification mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. The ST logo is a registered trademark of STMicroelectronics (c) 2001 STMicroelectronics - Printed in Italy - All rights reserved STMicroelectronics GROUP OF COMPANIES Australia - Brazil - China - Finland - France - Germany - Hong Kong - India - Italy - Japan - Malaysia - Malta - Morocco Singapore - Spain - Sweden - Switzerland - United Kingdom - U.S.A. http://w ww.st.com 6/6 |
Price & Availability of AN1352
 |
|
|
|
|
All Rights Reserved © IC-ON-LINE 2003 - 2022 |
| [Add Bookmark] [Contact Us] [Link exchange] [Privacy policy] |
|
Mirror Sites : [www.datasheet.hk]
[www.maxim4u.com] [www.ic-on-line.cn]
[www.ic-on-line.com] [www.ic-on-line.net]
[www.alldatasheet.com.cn]
[www.gdcy.com]
[www.gdcy.net] |