The RA55H4047M is a 55-watt RF MOSFET Amplifier Module for 12.5-volt mobile radios that operate in the 400- to 470-MHz range. The battery can be connected directly to the drain of the enhancement-mode MOSFET transistors. Without the gate voltage (VGG=0V), only a small leakage current flows into the drain and the RF input signal attenuates up to 60 dB. The output power and drain current increase as the gate voltage increases. With a gate voltage around 4V (minimum), output power and drain current increases substantially. The nominal output power becomes available at 4.5V (typical) and 5V (maximum). At VGG=5V, the typical gate current is 1 mA. This module is designed for non-linear FM modulation, but may also be used for linear modulation by setting the drain quiescent current with the gate voltage and controlling the output power with the input power.
The RA55H4047M is a silicon RF power module designed for 12.5‑V mobile radios operating in the 400‑470 MHz band. It delivers up to 55 W output power using three MOSFET stages and features low‑power gate control (1 mA typical) and a compact 66 × 21 × 9.88 mm package (code H2S). The module can be used for non‑linear FM modulation or linear AM modulation by adjusting gate voltage and input power.
The datasheet provides maximum ratings, electrical characteristics, typical performance curves, mechanical drawings, and detailed recommendations for construction, ESD protection, mounting, soldering, thermal design, and safety. It includes recommended screw torque (4.0‑6.0 kgf‑cm), heat‑sink thermal resistance (≈0.29 °C/W), and temperature limits to ensure reliable operation.
| Frequency Range | 400 – 470 MHz |
|---|---|
| Output Power | 55 W |
| Total Efficiency | 35 % |
| Gate Current (typ) | 1 mA |
| Package Code | H2S |
| Module Size | 66 × 21 × 9.88 mm |
| Operating Temperature Range | -30 °C to +110 °C |
| Storage Temperature Range | -40 °C to +110 °C |
| Recommended Screw Torque | 4.0 – 6.0 kgf‑cm |
M3 mounting screws should be tightened to a torque of 4.0 to 6.0 kgf‑cm.
The module case temperature should be kept below 90 °C, and preferably below 60 °C under standard conditions.