Qn9080 Internal DC-DC converter issue

[pavan252]

Hi

I am using Qn9080 for my application. As per data sheet i connected below circuit in my schematic.

pavan252_0-1606043517403.png

To enable internal DC-DC i connected as shown above but i am betting 0.6V after L1 inductor instead of 1.3V. Because of this low voltage i am unable to program my controller. VCC i am connecting as 3V.

By default the internal DC-DC converter will be enabled so it will convert high voltage of VCC to low voltage i.e 1.3V. But after assembling my PCB i am trying to program first time and the voltage at IDC is showing 3V but after L1 it's 0.6V. I am using the same values of inductors recommended in eval board. 

Please support.

Regards

Pavan.

[Sebastian_Del_Rio]

Hi Pavan, I hope you're doing well!

Could you please take a look at the Hardware Design Considerations application note for the QN908x?

Specifically, section 4.2 of this document, which describes the necessary connection, as well as steps to enable and disable this block.

Chapter 4.3 also contains some information about some of the external inductors and capacitors that we have verified for this part.

Please let me know if you need any more information.

Best regards,

Sebastián