I designed a two-stage cascaded amplifier circuit based on the QPA9121D, with an 8.2-ohm resistor placed at L9. I set the VPD to 1.8V, VCC to 5V, and VCC1 to 5V according to the datasheet. However, the final gain of the two-stage power amplifier is only around 35dB, and the P1dB is also around 18dBm. How can I adjust the circuit to achieve the output specified in the reference manual? I suspect the chip may not be operating in its normal state. How can I make sure the chip works properly?
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