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ADF7021 External Inductor VCO

Question asked by sss on Oct 26, 2017
Latest reply on Nov 6, 2017 by SteveH

Hi all,

 

How to select the the external inductor at Low RF frequency, 80 MHz ~ ?

 

For example,
VCO frequency is 80MHz *2*2 = 320MHz
Select inductor (Lext) is about 13nH ?
Is it correct ?

 

Datasheet say following,
"The second VCO, the external inductor VCO, uses an external inductor as part of its LC tank and supports the RF
operating band of 80 MHz to 650 MHz."

 

Figure 37. Direct RF Output vs. Total External Inductance
200~750MHz

 

AN-859,
Figure 6. ADF7020-1, ADF7021, and ADF7021-N Frequency vs. LEXT (L3) Using EVAL-ADF7020-1DBZx , EVAL-ADF7021DBZx, or EVAL-ADF7021-NDBZx Layout

 

Best regards,
sss

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