User's Manual

63
300W FM AMPLIFIER MODULE MFF0031AR0
DESCRIPTION
The Amplifier Module MFF0031A was designed to amplify FM carriers in the 87 - 108MHz band, and is
able to provide an output of 300W CW. Besides it is provided with an RF Monitor output with a level of -
40dBc ±3dB. In order to obtain the desired gain, the amplifier is made up by two gain stages: the pilot stage
uses a MOSFET BLF244, the final stage a MOSFET SD2942. An input adaptation circuit allows to adapt
the module to various driving levels. The adjustment of the output is achieved by controlling the power level of
the input signal. For both stages of the module there is a control terminal allowing to instantaneously disable
the MOSFETs if needed. The output of the module is completed by an 9
th
order (4 cells) Low-pass Filter to
attenuate the harmonic level of the esable signal, and by two high-directivity directional couplers needed to
sample part of the Forward and Reflected Power for measuring their levels.
TECHNICAL CHARACTERISTICS
Frequency Range 87 - 108MHz RF Output Impedance 50Ω
Output Power 300W Bias Current BLF244 with Vdd = +28V: 300mA
Input Return Loss >10dB Bias Current SD2942 with Vdd = +50V: 80mA
Power Supply +50V Gain 33dB (with 3dB interstage attenuation)
RF Input Impedance 50Ω Efficiency 54%
MFF0031AR0 COMPONENT LIST
Part Name/Number Description Qty.
00135 47Ω 1/2W RESISTOR 1
00664 LM35DT THERMAL SENSOR 1
01003 0.5pF CERAMIC CAPACITOR 1
01092 100pF MULTITURN CHIP 1
01400 BYPASSING CAPACITOR 1
01403 BYPASSING CAPACITOR 4
02209 PANEL MOUNTING N CONNECTOR 1
02514 PANEL MOUNTING SMB R114553000 2
04315 LM7805 VOLTAGE REGULATOR 1
04321 LM7812 VOLTAGE REGULATOR 1
04340A LM317HVT VOLTAGVE REGULATOR 2
05742 COVER 1
07907 TO220 INSULATOR 4
07910 TO220 INSULATOR 4
DET1326R0P DET1326R0 HEAT SINK 1
SCA0129R0B SCA0129R0 FM AMPLIFIER BOX 1
SCH0371BR0 INTERFACE BOARD 1
SCH0426AR0 FM AMPLIFIER INTERFACE BOARD 1
SCH0427AR0 300W FM AMPLIFIER BOARD 1