nRF52805 PCB layout example

[Emmanuel JEZ]

Hi,

1 - I don't understand why on the PCB layout example the track that is connected the L2 inductor is 762µm thick while the thickness of the pcb is 0.8mm?

2 - To have an impedance of 50 ohms with this track width, isn't it necessary to have a PCB with a lower thickness (0.4mm)?

3 - What are the functions of components L1, L2 and C3? Is it just a low-pass filter?

4 - Can the L1, L2 and C3 components be replaced by this reference 2450FM07A0035 from Johanson technology?

Thank you in advance for your help.

Best regards

[ketiljo]

1 - I don't understand why on the PCB layout example the track that is connected the L2 inductor is 762µm thick while the thickness of the pcb is 0.8mm?

 The impedance at this point isn't 50 ohm. More important to keep it short than to control the impedance. 

 

2 - To have an impedance of 50 ohms with this track width, isn't it necessary to have a PCB with a lower thickness (0.4mm)?

 See #1

 

3 - What are the functions of components L1, L2 and C3? Is it just a low-pass filter?

 Impedance transformation to 50 ohm and low pass filtering 

 

4 - Can the L1, L2 and C3 components be replaced by this reference 2450FM07A0035 from Johanson technology?

 No, this is designed for a another device with different impedance .