AM Radio Amplifier with Filter Using the 2SK3557

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)
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