400 Watt 80 Meter RF Amplifier

This Class E RF amplifier will deliver up to 400 watts of RF output, depending on the input voltage and tuning parameters (current). The amplifier uses inexpensive IXDD414 Driver ICs - one for every 2 MOSFETs. Transient Voltage Supressors (TVS devices) are used on the gates, drain bus and modulated DC input to the RF amplifier to protect the MOSFE
400 Watt 80 Meter RF Amplifier - schematic

Ts from damage due to accidental overvoltage. The carrier DC voltage should be between 40 volts and 50 volts, and no more than 135 volts at full positive peak modulation. The 8 MOSFET RF amplifier consists of two identical 4 MOSFET RF amplifier stages connected together in a single ended push pull configuration. Each amplifier stage (module) includes an RF driver (IXDD414 ICs), one IC for every 2 MOSFETs. The driver IC inputs are connected together to form a semi "bus", with a 100 ohm termination resistor connected to ground at each end of the driver bus, forming a 50 ohm termination. The drivers are connected to the VFO using 50 ohm coaxial cable. Each driver bus is driven out of phase with the other, so when one is "on" the other is "off". The outputs are also combined out of phase, giving the single ended, push pull configuration. TVS (TransZorb) devices are used on the drain and gate busses, and on the modulated DC input to each amplifier stage. Construction Notes: The shunt capacitors C-Shunt in the schematic are ATC (American Technical Ceramics) ATC100C series capacitors, 1000pF, 20% with MicroStrip (MS) termination. The MicroStrips are made from solid silver, and make it very easy to install and solder the capacitors into the circuit. The. 15uF RF bypass capacitors (C-Bypass) are made from 2 orange drop capacitors in parallel. 2 or 3 capacitors may be used in combination to obtain the desired capacitance value. The...

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