TPS61097-33 output voltage

Ali Tatari

I am using Tps61097 to boost 1.5v to 3.3v and I need Iout to be 30 mA but when I connect a load of 100 ohm at output the vout goes down to 2.5 v . I am using the components mentioned in the datasheet. Can someone please guide. Also i can't find the spice model for Tps61097.

over 13 years ago

0 Chris Glaser over 13 years ago

TI__Guru*** 142880 points

This is most likely caused by poor layout and/or an insufficient input supply. Is your input supply a lab supply or batteries, solar cell, etc? Try testing your board with a lab supply that can for sure supply the required current.

Also, you may have a non-optimal or poor layout. I recommend ordering the EVM and testing on its known good layout.

Can you post a picture of Vin, L, and Vout?

For spice models, please post to the analog elab forum.

0 Ali Tatari over 13 years ago in reply to Chris Glaser

Prodigy 250 points

I am using a arbitrary setup. On a copper plate I have put the components on proto board. i will send you the picture. I couldn't analog elab forum

0 Chris Glaser over 13 years ago in reply to Ali Tatari

TI__Guru*** 142880 points

The elab is here: http://e2e.ti.com/support/development_tools/analog_elab_and_tools/default.aspx

I'm not sure what you mean by arbitrary setup. I will await your picture of your layout.

0 Ali Tatari over 13 years ago in reply to Chris Glaser

Prodigy 250 points

no picture

0 Ali Tatari over 13 years ago in reply to Chris Glaser

Prodigy 250 points

At L

0 Ali Tatari over 13 years ago in reply to Chris Glaser

Prodigy 250 points

Vin and Vout are simple DC values at 1.5v and 2.5 v respectively.

0 Chris Glaser over 13 years ago in reply to Ali Tatari

TI__Guru*** 142880 points

Thank you for sending a picture of your setup.

Modern DC-DC converters switch with very fast frequencies and edge rates. Thus, the inductances/distances between the IC and its input and output caps and inductor must be minimized, as these are very high impedance at high frequencies. Extra wire creates a much larger loop area that frequently causes these kind of problems. You must build these circuits on a PCB where all the necessary components are close to the IC. A good idea is to follow/copy the layout of the EVM. Many times, customers deviate from this layout (even only slightly and they are still on the one PCB) and they have issues similar to yours. Layout is critical.

Please order the EVM to test this circuit.

0 Ali Tatari over 13 years ago in reply to Chris Glaser

Prodigy 250 points

I know breadboarding is not a good idea but what do you think about it...

0 Chris Glaser over 13 years ago in reply to Ali Tatari

TI__Guru*** 142880 points

I don't think it's a reliable way to test modern DC-DC converters at all.

0 Ali Tatari over 13 years ago in reply to Chris Glaser

Prodigy 250 points

I changed the setup and followed the layout given in data sheet and I was successfully able to meet my design requirements.

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TPS61097-33 output voltage