Hi,
I can't find decoupling capacitors in LMK03806's EVAL Board. Why?
For example, in the datasheet, i found that core current is 122 mA
In the EVAL Board, Vcc_core comes from the regulator via a ferrite bead which has 120 ohm at 100 MHz. The inductance of power supply is 120/(2*pi*0.1 GHz)=191 nH.
Cdecoupling must be greater than Power supply inductance/(impedance target)^2
Ztarget=voltage ripple/core current=300 mV/122 mA
finally, Cdecoupling= 32 nF.
The minimum number of capacitors n is equal to 2*Lparasitic/(Zt*trise).
trise in lmk03806 is 200 ps.
Is this approach of estimating decoupling capacitors incorrect?
If decoupling capacitors are not necessary as it is the case in LMK03806 EVAL Board, can someone, please, give me an explanation.
Thank you.
