TPS54202: Not able to draw any current from the chip with a load resistor, but no load conditions are 3.3 VDC output

Joseph Zuniga

Part Number: TPS54202

Can you breadboard this chip? I tried breadboarding it with a breakout board with support circuitry and I am able to get the 3.3 VDC output. However when I put a load resistor on the output to draw 1.5 A, I am not able to draw any current at all.

over 8 years ago

0 JohnTucker over 8 years ago

TI__Guru**** 191445 points

What kind of breadboard? Does it use point to point wiring? Generally you will need a purpose built PCB with appropriate trace widths, copper fills and ground plane if you expect to draw any output current. See the datasheet figure 31 and the EVM users guide figures 15 and 16 for layout details.
www.ti.com/.../tps54202
www.ti.com/.../slvuap3

0 Joseph Zuniga over 8 years ago in reply to JohnTucker

Prodigy 30 points

I am using just a standard solderless breadboard. I notice that when connecting a load to the output and looking at the signal through an oscilloscope, the output voltage drops to around 300 mV. Connecting an ammeter, I am measuring no current. So drawing current really does depend on the layout of the IC and support circuitry format, corresponding to the suggestions in the datasheet?

0 JohnTucker over 8 years ago in reply to Joseph Zuniga

TI__Guru**** 191445 points

This topic comes up from time to time. While it may not be impossible to prototype a switching power supply on a breadboard, everyone who has posted here about it has had problems such as yours. You might want to consider acquiring an official EVM:

www.ti.com/.../tps54202evm-716

That PCB is known to work and you can modify it to your circuit requirements.

0 Joseph Zuniga over 8 years ago in reply to JohnTucker

Prodigy 30 points

Just curious, what are the wattage ratings on the output resistance network resistors on the EVM?

0 JohnTucker over 8 years ago in reply to Joseph Zuniga

TI__Guru**** 191445 points

Are you inquiring about the feedback resistor divider? We typically use 1% 0.1 W resistors.

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TPS54202: Not able to draw any current from the chip with a load resistor, but no load conditions are 3.3 VDC output