CC2541: CC2541 : decoupling capacitor

sohn

Prodigy 40 points

Part Number: CC2541

Hello,

Most reference design schematic use different values of decoupling capacitors for each VDD.

I wonder what electrical characteristics have chosen that value.

Regards

over 6 years ago

0 Fredrik K over 6 years ago

TI__Guru** 106705 points

Hi Sohn,

As you can see, most of these are general purpose decoupling, 100 nF. Some are larger, 1 uF, due to decoupling large internal current consumers such as LDOs. The 220 pF is chosen due to RF frequency response.

Regards,
Fredrik

0 sohn over 6 years ago in reply to Fredrik K

Prodigy 40 points

Thank you for your answer.

Which part of the datasheet does it take to see that RF frequency response is different?

If there is no reference schematic, I wonder how can know the value.

Regards,

Sohn

0 Fredrik K over 6 years ago in reply to sohn

TI__Guru** 106705 points

Hi Sohn,

I am not sure I understand your last post. The figure in your original post was copied from a reference design for CC2541, right? The recommendation is to follow the reference design and use the same component values.

Regards,
Fredrik

0 sohn over 6 years ago in reply to Fredrik K

Prodigy 40 points

Hi Fredrik,

Thank you for your answer. It's helped a lot.

Regards,

Sohn

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CC2541: CC2541 : decoupling capacitor