915MHz Power Amplifier RF2155 circuit diagram

  
As shown in FIG constituted by 915MHz RF2155 power amplifier application circuit. Radio frequency (RF) signal from the input pin 7, after the preamplifier, after the last stage
915MHz Power Amplifier RF2155 circuit diagram - schematic

power amplifier output is amplified by 11 feet. 7 feet and the internal amplifier is directly coupled, it is proposed in 7 feet plus a UHF blocking coupling capacitors. Since there are four possible gain settings, so a series with the input 6.8nH inductance. Final PA is a mismatch collector transistor output terminal 11 feet and 14 feet are connected inside the chip, 14 feet as the final stage amplifier power supply terminal, providing a bias current through these pins to the final amplifier. 14 feet as a secondary harmonic filter circuit, effectively shorting the second harmonic, using transmission lines as about 500mils inductance and 33pF capacitance of the filter (near Vcc may be placed at a tantalum capacitor). 8 feet to power control pin (PC), you can control the pin voltage to control the power supply. When the voltage is low (0V), the amplifier power supply is turned off; when the voltage is high (3V), the amplifier is in full power operation. 8-pin external UHF or HF filter capacitor. 15 and 16 feet for the RF power gain control terminal, control the output power gain of 8dB bit step and 16dB bit step, these feet high at least 2.7V, shall not exceed 3.3V, while an external UHF bypass capacitor.




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