RF2131 optimal efficiency power amplifier circuit when powered by 4.8V power supply

As shown in the figure, this is the best efficiency power amplifier circuit of RF2131 when it is powered by 4.8V power supply. The radio frequency signal (RF) is input from pin 7, and is amplified by the preamplifier and the final power amplifier and output from pins 10, 11, 14, and 15. Pin 7 is directly coupled to the internal amplifier, so a DC-blocking coupling capacitor is added to pin 7; the input impedance of pin 7 is 50Ω, but the exact impedance value is determined by the internal inter-stage matching network connected to pin 3. The output pins 10, 11, 14, and 15 are connected inside the chip. Usually, pins 10, 11, 14, and 15 are connected together externally as signal outputs. Attention should be paid to symmetry, otherwise the circuit will be unstable. The output matching network matches the output impedance of the amplifier to obtain the maximum output power and efficiency; at the same time, these pins are also used as the power supply end of the final power amplifier, and bias current is provided to the final power amplifier through these pins. Pin 1 is connected to the power control pin (PC), and the voltage of this pin can be controlled to control the power supply power. At room temperature, when the voltage is low (0.5V or less), the amplifier is in the power-off state.