FM Radio Amplifier with Filter Using the 2SC347A Application Note Overview This application note explains about ON Semiconductor s 2SC347A which is used as a Low Noise Amplifier (LNA) for FM Radio. http://onsemi.com The 2SC347A is a silicon bipolar transistor best suited for high-frequency applications which is assembled in the 3-pin surface mount package of the high collector dissipation. For information about the performance, please refer to the datasheet of this product. Since the evaluation board is adjusted to achieve optimal performance in worldwide FM band, the product can provide 22. gain and 1.6 noise figure. A standard material FR4 is used for the printed circuit board (PCB). Please note that the losses of the PCB and the SMA connector are not excluded from the noise figure. Semiconductor Components Industries, LLC, 214 1 Publication Order Number: September 214- Rev. AND2SC347A_1/D
Summary of Data Ta = 2ºC, Input Power = -4 m, Zo = 7 Ω Parameter Symbol Condition Result Unit DC Voltage Vcc V DC Current Icc 12.6 ma f = 76 MHz 22.7 Power Gain Gp f = 9 MHz 23. f = 18 MHz 22. Noise Figure *Zo = Ω NF f = 76 MHz 2. f = 9 MHz 1.7 f = 18 MHz 1.6 f = 76 MHz 21. Input Return Loss RLin f = 9 MHz 18.3 f = 18 MHz 12. f = 76 MHz 12.6 Output Return Loss RLout f = 9 MHz 13.3 f = 18 MHz 1.1 f = 76 MHz 29. Isolation ISL f = 9 MHz 27.8 f = 18 MHz 26. Gain 1 Compression Input Power Pin1 f = 1 MHz -17 m Input 3rd order Intercept Point IIP3 f1 = 1 MHz f2 = 11 MHz Pin = -3m -8 m * Noise Figure includes the loss of PCB and SMA connector. 2
Circuit Design Vcc = V R1 R2 C8 C6 L C7 INPUT L1 C1 C2 R3 C3 L3 L4 OUTPUT R L2 TR1 C4 R6 R4 C Evaluation Board 3
Bill of Materials Item Symbol Value Manufacture Size Bip-Tr TR1 2SC347A ON Semiconductor SC-62 C1 22 pf Murata GRM1 1 C2 82 pf Murata GRM1 1 C3 22 pf Murata GRM1 1 Capacitor C4 2 pf Murata GRM1 1 C 1 pf Murata GRM1 1 C6 1 pf Murata GRM1 1 C7.1 uf ROHM MCH182CN 168 C8.1 uf ROHM MCH182CN 168 R1 39 kω Various 168 R2 39 Ω Various 1 Resistor R3 2.2 kω Various 1 R4 1 Ω Various 1 R 1 kω Various 1 R6 1 kω Various 1 L1 1 nh TDK MLG1S 1 L2 82 nh TOKO LL1-FH 1 Inductor L3 12 nh TOKO LL168-FS 168 L4 39 nh TDK MLG1S 1 L 1 nh TOKO LL168-FS 168 Material FR-4 2 x 16 mm 4
Measurement Results Power Gain 3 2 2 1 1 Isolation 2 2 3 3 4 4 1 1 2 1 1 2 Figure 1 Power Gain vs. Frequency Figure 2 Isolation vs. Frequency Input Return Loss 1 1 2 2 Output Return Loss 1 1 2 2 3 3 3 1 1 2 Figure 3 Input Return Loss vs. Frequency 3 1 1 2 Figure 4 Output Return Loss vs. Frequency S(3,3) 9 MHz S(4,4) 9 MHz freq 7 (7.MHz to to 11 11.MHz) MHz freq 7 (7.MHz to to 11 11.MHz) MHz Figure Smith Chart S11 Figure 6 Smith Chart S22
Measurement Results Zo = Ω 4 3. 4 2 S21 Noise Figure 3 2. 2 1. 1 S11,S21,S12,S22 2 4 6 S11 S12 S22. 8 6 7 8 9 1 11 12 1.1 1 1 1 1 Figure 7 Noise Figure vs. Frequency Pin = -3 m Figure 8 Wide Span 1 1 Output Power m 1 1 2 4 3 3 2 2 1 1 Input Power m Figure 9 Output Power vs. Input Power Figure 1 Input 3rd order Intercept Point 6
Gain 1 Compression Input Power (Pin1) Pin1 is measured the input power level when the power gain increase more 1 than that of linear range. Input 3rd order Intercept Point (IIP3) IIP3 is defined by the following equations. APPLICATIONS INFORMATION IIP3 = Pin + (IM3 / 2) (eq. 1) ON Semiconductor and the ON logo are registered trademarks of Semiconductor Components Industries, LLC (SCILLC) or its subsidiaries in the United States and/or other countries. SCILLC owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of SCILLC s product/patent coverage may be accessed at www.onsemi.com/site/pdf/patent-marking.pdf. SCILLC reserves the right to make changes without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitabilityof its products for any particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. Typical parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including Typicals must be validated for each customer application by customer s technical experts. SCILLC does not convey any license under its patent rights nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applicationsintended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner. 7