LM5019: Voltage at Vfb is showing as 1.288V.

Charan Kumar Reddy K R

Part Number: LM5019

We are using LM5019 in one of our designs. Voltage at Vfb is showing as 1.288V and Output voltage measured is 3.462 V. Required output voltage is 3.3V.

Please let us know what could be the issue?

Schematics of LM5019.

R9 is replaced with 1 Ohm.

over 2 years ago

0 Andy Chen over 2 years ago

TI__Mastermind 27045 points

Hi Charan,

Pls download LM5019 Calculator to assist the circuit design:

https://www.ti.com/lit/zip/snvc056

improper ESR may cause output shift

B R

Andy

0 Charan Kumar Reddy K R over 2 years ago in reply to Andy Chen

Prodigy 80 points

Hi Andy,

Yes we have used the same calculator for the circuit design.

Still we are not getting the correct voltage values. What could be reason for measured Vfb out of range.

Regards,

Charan.

0 Andy Chen over 2 years ago in reply to Charan Kumar Reddy K R

TI__Mastermind 27045 points

Hi Charan

Is Vin=48V?

Can you upload PCB layout for checking?

B R

Andy

0 Charan Kumar Reddy K R over 2 years ago in reply to Andy Chen

Prodigy 80 points

Hi Andy,

Vin = 54V

Could you please share your mail ID to share Layout file.

Regards,

Charan.

0 Andy Chen over 2 years ago in reply to Charan Kumar Reddy K R

TI__Mastermind 27045 points

Hi Charan,

Let's talk about it in email andy.chen@ti.com, I will close this thread.

B R

Andy

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LM5019: Voltage at Vfb is showing as 1.288V.