TPS54428: For VIN=5V, Vout=3.3V

Lee, Sam

Part Number: TPS54428

Hi team,

I'm using webench simulation of TPS54428, but it's not avaible to simulate it from IOUT=2.2A (VIN=5V/ Vout=3.3V) in the webench.

So, TPS54428 can't support the following conditions?

VIN = 5V

VOUT=2.5V / IOUT = 2.5A (average)

Thanks,

Sam Lee

over 7 years ago

0 Gavin Wang (Zejing) over 7 years ago

TI__Expert 3480 points

1. Pls upload your webench design. Share your link.
2. What 's the meaning of " not avaible "? Vout drop or unstable or other abnormal ??
3. Pls clarify your question. Vin=5.5V, Vout=3.3V or 2.5V? Iout=2.2A or 2.5A? Which case do you want to ask?
4. What' s your application? Why do you need that low dropout case?

0 Lee, Sam over 7 years ago in reply to Gavin Wang (Zejing)

TI__Expert 6025 points

Hi Gavin,

Sorry. I correct the typo.

Noraml condition:

VIN=5V, VOUT=3.3V, IOUT=2.5A

The simulation result is as follows.

Thanks,

Sam Lee

0 Gavin Wang (Zejing) over 7 years ago in reply to Lee, Sam

TI__Expert 3480 points

What' s your application? Why do you need that low dropout case?

0 Lee, Sam over 7 years ago in reply to Gavin Wang (Zejing)

TI__Expert 6025 points

Garvin,

The application is printer. A customer selected the device arbitrarily but I'm checking if it can be used. If not, can you recommend some devices for the conition?

Thanks,
Sam Lee

0 Gavin Wang (Zejing) over 7 years ago in reply to Lee, Sam

TI__Expert 3480 points

It 's OK for VIN=5V, VOUT=3.3V, IOUT=2.5A.

But the webench only support D<0.65.

0 Lee, Sam over 7 years ago in reply to Gavin Wang (Zejing)

TI__Expert 6025 points

Gavin,

Thank you for your answer. I'd like to check one more.
Is it still okay for VIN=5V, VOUT=3.3V, IOUT=4A?

Thanks,
Sam Lee

0 Gavin Wang (Zejing) over 7 years ago in reply to Lee, Sam

TI__Expert 3480 points

Of course, it is 4A device.

0 Anthony Lang over 7 years ago in reply to Lee, Sam

TI__Expert 4875 points

Hi Sam,

If customer could accept the thermal and load transient performance, 5V to 3.3V /4A could be supported. For high duty or LDO mode operation, most of the inductor current( RMS=Iout) will be on HSFET. HSFET usually has bigger Rdson so the power dissipation will be higher due to more conduction loss. And large duty operation has worse load transient performance than small duty application due to DCAP2 control.

Power management

Power management forum

TPS54428: For VIN=5V, Vout=3.3V