434MHz LNA for RKE Using the 2SC5490A Application Note http://onsemi.com Overview This application note explains about ON Semiconductor’s 2SC5490A which is used as a Low Noise Amplifier (LNA) for RKE (Remote Keyless Entry). The 2SC5490A is a silicon bipolar transistor best suited for high-frequency applications which is assembled in the 3-pin surface mount package. For information about the performance, please refer to the datasheet of this product. Since the evaluation board is adjusted to achieve optimal performance in RKE (434 MHz), the product can provide 14.6dB gain and 1.45dB 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, 2014 April, 2014 – Rev. 0 1/10 434MHz LNA for RKE Using the 2SC5490A ■Summary of Data Ta = 25 °C, Input Power = -40 dBm Parameter DC Voltage DC Current Power Gain Noise Figure Input Return Loss Output Return Loss Isolation Gain 1dB Compression Input Power Input 3rd Order Intercept Point Symbol Condition Result Unit Vcc 3.0 V Icc 1.96 mA Gp f = 434 MHz 14.6 dB NF f = 434 MHz 1.45 dB RLin f = 434 MHz 5.6 dB RLout f = 434 MHz 12.3 dB ISL f = 434 MHz 19.5 dB Pin1dB f = 434 MHz -20 dBm IIP3 f1 = 433 MHz f2 = 434 MHz -10 dBm Pin = -35 dBm 2/10 434MHz LNA for RKE Using the 2SC5490A ■Circuit Design Vcc = 3V C5 R1 R2 C4 L2 L1 OUTPUT INPUT L3 C1 C3 C2 TR1 L4 ■Evaluation Board 3/10 434MHz LNA for RKE Using the 2SC5490A ■Bill of Materials Item Symbol Value Manufacturer Size Bip-Tr TR1 2SC5490A ON Semiconductor SC81 C1 C2 10 pF 6 pF Murata GRM155 Murata GRM155 1005 1005 C3 4 pF Murata GRM155 1005 C4 150 pF Murata GRM155 1005 C5 0.1 uF Various 1608 R1 680 Ω Various 1005 R2 68 kΩ Various 1608 L1 22 nH TDK MLG1005S 1005 L2 10 nH TDK MLG1005S 1005 L3 39 nH TDK MLG1005S 1005 L4 2.2 nH TDK MLG1005S 1005 - FR4 - 19 x 12 mm Capacitor Resistor Inductor Material 4/10 434MHz LNA for RKE Using the 2SC5490A Power Gain ‐ dB ■Power Gain 20 18 16 14 12 10 8 6 4 2 0 0 200 400 600 Frequency ‐ MHz 800 1000 200 400 600 Frequency ‐ MHz 800 1000 Isolation ‐ dB ■Isolation 0 ‐5 ‐10 ‐15 ‐20 ‐25 ‐30 ‐35 ‐40 ‐45 ‐50 0 5/10 434MHz LNA for RKE Using the 2SC5490A ■Input Return Loss Input Return Loss ‐ dB 0 ‐5 ‐10 ‐15 ‐20 ‐25 ‐30 0 200 400 600 Frequency ‐ MHz 800 1000 200 400 600 Frequency ‐ MHz 800 1000 ■Output Return Loss Output Return Loss ‐ dB 0 ‐5 ‐10 ‐15 ‐20 ‐25 ‐30 0 6/10 434MHz LNA for RKE Using the 2SC5490A Noise Figure ‐ dB ■Noise Figure 5 4.5 4 3.5 3 2.5 2 1.5 1 0.5 0 300 350 400 450 500 Frequency ‐ MHz 550 600 S11,S21,S12,S22 ‐ dB ■S11, S21, S12, S22 Wide Span 20 10 0 ‐10 ‐20 ‐30 ‐40 ‐50 ‐60 ‐70 ‐80 S21 S11 S22 S12 10 100 1000 Frequency ‐ MHz 10000 7/10 434MHz LNA for RKE Using the 2SC5490A S(3,3) ■Smith Chart Input Return Loss 434 MHz fre400 q (400.0MHz 500.0MHz) MHz toto500 MHz S(4,4) ■Smith Chart Output Return Loss 434 MHz fre400 q (400.0MHz 500.0MHz) MHz toto500 MHz 8/10 434MHz LNA for RKE Using the 2SC5490A ■Gain 1dB Compression Point 0 Output Power ‐ dBm ‐5 ‐10 ‐15 ‐20 ‐25 ‐30 ‐45 ‐40 ‐35 ‐30 ‐25 ‐20 Input Power ‐ dBm ‐15 ‐10 ■Input 3rd Order Intercept Point f1 = 433 MHz, f2 = 434 MHz, Pin = -35 dBm 9/10 434MHz LNA for RKE Using the 2SC5490A ON Semiconductor and the ON logo are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). 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 suitability of 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 applications intended 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. 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