Linear Amplifier Module Powers 20 to 512 MHz (.PDF Download)

Sept. 28, 2017
Linear Amplifier Module Powers 20 to 512 MHz (.PDF Download)

Low-distortion modulated signals are required for communications systems, which is the forte of the RFM20-512-350-HSD power-amplifier (PA) module from RF and Microwave Power Technology LLC: It provides clean amplification of communications signals from 20 to 512 MHz.

The Class A/AB PA module delivers 350 W output power at 1-dB compression, with high gain and high efficiency. It also includes numerous monitoring and protection circuits to help a user achieve safe operation. The PA module is a good fit for commercial and military communications systems that require high gain to transform low-level input signals at typically −2.3 dBm into high-level output signals for transmit purposes.

The RFM20-512-350-HSD (see figure) achieves at least 54.7-dB gain and typically 57.7-dB gain across the full frequency range, with worst-case gain flatness of ±1.2 dB and typical gain flatness of ±0.6 dB. It operates on two power supplies, drawing maximum current of 3.5 A from a voltage supply of +24 to +28 V dc and a maximum of 15 A from a voltage supply of +46 to +50 V dc.

Not So Hot

The robust amplifier is built to take whatever excess heat its output stage generates, with a nickel-plated copper base for efficient thermal flow away from the active device. It is also generously equipped with control and monitoring functions for protection, such as output-stage current sensing, an alarm when the package base exceeds +60ºC, and an output disable function with a response time of better than 1 μs. When combined, for example, with a user’s own VSWR-monitoring circuitry, the amplifier can be quickly shut down in the event of impedance-mismatch conditions.