CC2640R2F: Switching Between DC/DC and Global LDO

Lawrence Wong

Part Number: CC2640R2F

Customer current design have been using the DC/DC mode with a 10uH inductor between DCDC_SW and VDDR. From Customer:

It appears that the chip switches between these two modes for best efficiency, using Global LDO mode even though there is a inductor installed.

Customer question is – can they configure the chip to ONLY use Global LDO mode but leave the inductor installed on the board?

Question from me - Is there any benefit in doing this?

over 5 years ago

0 Vegard H over 5 years ago

TI__Expert 4560 points

If you read section 11.3 in the linked document, you can see how to force the Global LDO to be used instead of the DCDC. If you are not going to remove the inductor to save on BOM cost, then I don't see many benefits of not using the DCDC converter. Only using the GLDO will give you a higher power consumption.

Vegard

0 Lawrence Wong over 5 years ago in reply to Vegard H

TI__Genius 15770 points

Thanks. Also if the customer needs to, is it ok to dynamically switch between DC/DC and LDO? The need is to take sensitive measurement and the DC/DC switching noise has and an impact to the measurement.

Regards,

Lawrence

0 Simon J over 5 years ago in reply to Lawrence Wong

TI__Genius 11810 points

Hi Lawrence,

You need to reboot the device to be able to switch between DCDC and LDO, it's not possible to change run-time.

-Simon

0 TER over 5 years ago in reply to Simon J

TI__Guru**** 317180 points

" the DC/DC switching noise has and an impact to the measurement.": As far as I know we have not seen an impact on anything else than sensitivity (for poor layout boards) when using DCDC so it would be useful with more details here.

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CC2640R2F: Switching Between DC/DC and Global LDO