ADL5324 Datasheet

Question

Hi, 
 In the ADL5324 datasheet there are reference designs and layouts. 
 On page 19, figure 17, the layout for the 3500-3700MHz operation. There is a series inductor on the output, L2. 
 It is 4.7nH. 
 At 3500MHz, this gives a reactance of 103 ohms. 
 Considering the output impedance is 50 ohms, this will attenuate the output signal somewhat.... 
 Am I correct? 
 If so what value should this be? 
 Best regards, 
 Roger.

Jim · Accepted Answer

Hi Rog, 
 Analog devices does not offer a transistor based models for RF amplifiers. There may be some error between ADS and built matching circuits. I have noticed this at some of the higher frequencies. So that may be why you have a different value inductor. My trick when that happens, is to shift the frequency by the delta between the ADS freq and the freq the part is actually tuned to in real life. After 2nd simulation with the offset, I find the tuning is spot on. 
 Regards, 
 Jim B)

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ADL5324 Datasheet