TPS65266 No Output when supplied with 5V

Haydn,

1. check R19: if the value correct- 51.3k ohm(do not solder a wrong resistor)? if the solder well? check pin 20 ROSC voltage, about 0.5V

2. check pin 21 AGND. If connect to GND well?

3. double check Inductor value. why need 47uH? I think 4.7uH is good.

if the issue can't be solved, send me PCB LAYOUT.

Let me know your feedback.

Jason Wang

Hi Jason,

Thanks for the quick reply.

I've checked all of the pins and I'm sure that they've been soldered well. I can't try with a 4.7uH inductor as I don't have any lying around.

I use a 3.3V plane on the top layer that I've removed for clarity. 

Here is my PCB layout:

Haydn,

From you layout, i think you didn't design DC/DC power before.

The layout is poor. The trace width for VIN, PGND, LX and input capacitor/oup capacitors GND trace are too narrow. Also, Cin should near Vin pin.

Please refer TPS65266 datasheet 32 layout guide, also you can find TI local FAE to guide you.

Jason Wang