LM3489: Kindly review the power supply section

Aswin S Dharman

Part Number: LM3489

Requirements: Designed for a variable input with (5-20v), but need a constant output of 5V,2A

Please find the below-attached schematics and let me know your valuable comments. If the chosen components are wrong for our application, kindly share the essential parts. Please do the review as soon as possible.

over 3 years ago

0 Gui He over 3 years ago

TI__Mastermind 27996 points

Hi Aswin

Do you have a ESR spec for the output capacitor C4& C3 ? That defines the operate frequency.

And also the part number or the RDSON for the PFET, which impact the current limit and the RADJ selection.

Thank you.

0 Aswin S Dharman over 3 years ago in reply to Gui He

Intellectual 350 points

RDSON for the PFET(PMDPB70XP,115) is 87mOhm maximum

Kindly share a detailed review report, and please ensure that it is apt for my application, which is mentioned above.

0 Gui He over 3 years ago in reply to Aswin S Dharman

TI__Mastermind 27996 points

And kindly share the ESR for output capacitor please.

0 Gui He over 3 years ago in reply to Aswin S Dharman

TI__Mastermind 27996 points

Also, LM3489 is a device works at hysteretic mode, The frequency will vary across the variable Vin. Is there any reason you choose this device? I would recommend you to use one fixed frequency PWM control device with a RT pin.

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LM3489: Kindly review the power supply section