Application Note AM Radio Amplifier Module with Filter Using the 2SK3557 January 2014 Feature of AMAM-band Amplifier Module ・J-FET : 2SK3557 ・High Gain : Ga=9.6dB @1MHz (Zo=50Ω) ・Excellent Gain Flatness : ∆Ga1<0.3dB ・Low Gain Variation : ∆Ga2<1.1dB for VDD=3~8V ・High FM Suppression : <-80dB ・High Impedance at INPUT/OUTPUT Port AM-band Amplifier Module (Zo=50Ω) Parameter Frequency Unit AM-band FM-band [MHz] 0.52~1.71 76~108 VDD [V] 5 IDD [mA] 16.8 Ga [dB] 9.6 <-80 ΔGa1 *1 [dB] 0.28 - *2 ΔGa2 *1 *2 [dB] 1.05 - Input Impedance [Ω] High - Output Impedance [Ω] High - *1 : Ga Variation within AM-band *2 : Ga Variation for VDD=3~8V Block Diagram of AMAM-band Amplifier AM J-FET IN OUT Board of AMAM-band Amplifier Module 2SK3557 (J-FET) VDD=5V IN IN OUT OUT Circuits of AMAM-band Amplifier Module VDD=5V-16.8mA C7 L4 C2 IN C4 L1 L2 R3 C3 R6 L3 OUT C6 FET1 R2 R7 R1 C1 R4 R5 C5 Bill of Materials Item Symbol Value Manufacturer Size JFET FET1 2SK3557 ON Semiconductor SC59 Capacitor C1 10 pF TAIYOYUDEN 1005 C2 12 pF Murata GQM1882C1H120 1608 C3 120 pF TAIYOYUDEN 1005 C4,C5,C6,C7 0.1 uF ROHM MCH182CN104KK 1608 R1 22 kΩ Various 1608 R2 270 Ω Various 1608 R3 120 Ω Various 1608 R4 100 kΩ Various 1608 R5 10 Ω Various 1608 R6 150 Ω Various 1608 R7 100 kΩ Various 1608 L1,L2,L3 3.3 uH TDK NLV25T-3R3J-PF 2520 L4 330 uH TDK NLCV32T-331K-PF 3225 - FR4 JF-2A 25.4 X 12.7 mm Resistor Inductor Material Characteristics of Gain Zo=50Ω AM FM Ga = 9.6dB in AM-band (0.52~1.71MHz) Ga < -80dB in FM-band (76~108MHz) Ga=9.41dB @0.52MHz Ga=9.69dB @1.00MHz Ga=9.51dB @1.71MHz ∆Ga1=0.28dB within AM-band Gain vs VDD Zo=50Ω ∆Ga2＝1.05dB for VDD=3～8V Characteristics of Impedance S(2,2)__OUTPUT S(1,1)__INPUT Zo=50Ω VDD=5V freq (520.0kHz to 1.710MHz)