RF Choke SRF
To reduce the Q factor, can I series a low value resitor with the choke?
Now I am working toward a 433MHz 8dBm power amplifier at 2.5V supply under CMOS process. And I am wondering about the optimum load impedance where largest power can be obtained. With some simulations, I found that the optimum load changes with the choke value changes. For example, choke 33nH with Zopt 38-j175 ohm,but choke 100nH with Zopt 166-j435 ohm. Even when the choke value reaches 1uH, the Zopt changes to 1666ohm. I don't know why this will happen.
Added after 5 minutes:
Still another question. Can we still use the equation of Zopt=VDD/(2*Po) under my condition?
If I can use it, the choke has to be as large as 150nH. Actually I get good performance with 33nH choke.
If I should not use this equation to determine the optimum load, which should I choose. Or just through simulation?