TPS63061 schematic problems.

Hi Andres,

Do you have an input capacitor close to the TPS63061? It is not obvious in your schematic.
If yes, which value is it?

Regards,
Michael

Hello Michael,

Sorry, but I have not attached this part, there are some capacitors in Vin and a resistor (20k) in Vout:

Thanks a lot.

Andrés S.

Thanks Andres,

could you please post your layout of the TPS63061?

Regards,
Michael

Hi Michael, I have changed the design, and I have only this schematic and the Arduino yun and srf01 sensors, but it is normal connection:

And I have a lot of unusual problems, for example, if battery is connected and the button was switched on, it doesn't work, it only returns 5v and 30 mA (for example with a Arduino Leonardo it works fine because it need only 27mA), but if the battery is connected and the button was switched off, I wait X milliseconds and I switch on the button, the it works fine (in a protoboard).
Now, if I do the same process soldering the Arduino yun and 4 srf01 sensors, then it returns only 1.92V, and if I test the same board in the protoboard, it keep returns 1.92V (maybe it is a cable dimension problem), I have no idea that would be the problem. Could you help me with this new terms?

Thanks a lot.

Andrés

The C1 and C2 are polarized capacitors.

Hi Andres,

first you will have to use low ESL ceramic capacitors as recommended in the DS.

To help you i need to understand how your setup looks like.
Could you please post your layout or a picture how the TPS63061 is connected?

Thanks,
Michael

I am using non-recommended by Datasheet component in my design, the inductor is this: uk.farnell.com/.../1463478, and the rest of ceramic capacitors, I have used a tipical ceramical capacitor (with same value) in stock in my near electronic shop. Can it be the problem? Should I change it?
I can't post here the layout, it will be used in my thesis and it is not recommendable, sorry. Can I send you a Email with the layout?

C1 and C2 are no ceramic caps right? You should change them.

The Inductor you sent has value of 10uH. In your schematic is a 1uH value.
Please use an Inductor within the recommended values and proper current ratings.

You could send the layout to me: m-helmlinger@ti.com

Sorry, I have mistaken, the inductor is this one: es.farnell.com/.../1463503, in the first version there are C1 = 10.1uF as Ceramic and 100uF as Tantalium and C2= 0.1uF as Ceramic capacitor , and the new version has a C1= 22uF as Electrolitic capacitor, and C2 = 22uF or 0.1uF as electrolitic capacitor.

I will write you soonest.
Thanks a lot.

Ok. The inductor should be fine.

As recommended in the DS please use ceramic input capacitors at least 20uF and place them directly to the Device input.
You could use an electrolytic bulk capacitor in addition.

I will wait for your layout.

Regards

Hi Andres,
thanks for the layout files.

This design cannot work. You placed the passive components far away the device without following the guidelines in our Datasheet page 21.


I recommend to copy the Layout of the TPS63060EVM: www.ti.com/tool/TPS63060EVM-619


To get a general understanding of a good SMPS PCB layout you can have a look into this paper: www.ti.com/.../slyt614.pdf
It describes step by step a good PCB layout for a buck converter.

Regards,
Michael

Hello Michael,

Have you seen the Email? I am going to change the capacitor today, and I hope it works, Have you found any problem?

Thanks a lot.
Best regards.

Sorry, I have not watched your answer,
I am going to see this links.
Thanks a lot.