WEBENCH® Tools/LMR14006: Power Supply Design

divyanshu bawa

Expert 1325 points

Part Number: LMR14006
Other Parts Discussed in Thread: LMR14020, TPS560430,

Tool/software: WEBENCH® Design Tools

Dear Sir,

I have a query to make a power supply design for my device, the requirements are as follows:

V(In) = 28v

V-max(in) = 33v

Iout-max = .6amp

V-out = 3.3v

We had made some design with respect to WE-BENCH, can u please look into the design and cross check these two designs. I made some changes with the package of resistor to 0402 of All circuits which are 0201 as per the actual design and changed 0201 package of RFBB to 0603 (RFbb) only in LMR14020.

Please look into thisLMR14006X.pdf LMR14020.pdf

over 6 years ago

0 Praveen Badiger over 6 years ago

TI__Expert 8365 points

Hi Divyanshu,

We didn't observe the resistor with 0201 packages in the actual design. Could you please share the actual design with us using 'Share Design' option.
However please note, you can select the resistor with the required package in alternate part selection. The package size does not affect the electrical characteristics of the circuit. The change in the package size will only affect on PCB and thermal behavior. Any change in the component selection will update the WEBENCH design and same is being validated by WEBENCH.

Thanks & Regards,
Praveen B

0 Andy Chen over 6 years ago

TI__Mastermind 34745 points

Hi,

100pF Cff cap on LMR14020 circuit should be OK.

There is no limitation on resistor package size as long as power rating is OK.

You may also try latest TPS560430 which has smaller solution size.

0 divyanshu bawa over 6 years ago in reply to Andy Chen

Expert 1325 points

I have uploaded power supply design please look into this and reviews the design with there proper package of components.

0 Praveen Badiger over 6 years ago in reply to divyanshu bawa

TI__Expert 8365 points

Hi Divyanshu,

The above design shared by you does not have any information. Could you please share the WEBENCH design link using 'Share Design' option as shown below.

0 divyanshu bawa over 6 years ago in reply to Praveen Badiger

Expert 1325 points

6457.LMR14006X.pdfhi

Please look for LMR14006XDDRC Design first. I am attaching you the pdf file for the same. Please look into this

0 divyanshu bawa over 6 years ago in reply to divyanshu bawa

Expert 1325 points

waiting for your reply

thanks

0 Andy Chen over 6 years ago in reply to divyanshu bawa

TI__Mastermind 34745 points

Hi,

Below my comments on LMR14006X circuit:

1. Ton is 100ns for 33V to 3.3V at 1.1MHz, there is no enough margin as LMR14006 Ton-min typical is 95ns, average switching freq will drop a little if Ton-min is hit. or you can use TPS560430 with Ton-min 60ns.
2. D1 can be 40V diode for lower cost.
3. other design is OK.

0 divyanshu bawa over 6 years ago in reply to Andy Chen

Expert 1325 points

Thanks for your reply. I do have other query with another power supply which is as below : There are few changes i did with the package of resistor and Capacitor please look into this.

CFF is 0603 package but in actual it was 0201

Rbb is 0603 Package but in actual it was 0201.

Please check for the noise into the Pcb as there layout will changed due to bigger components..

Waiting for your early reply3034.LMR14020.pdf

0 divyanshu bawa over 6 years ago in reply to divyanshu bawa

Expert 1325 points

Hi Andy

Please look for the 2nd design also. I am waiting from your side to confirm the design.

Thanks

0 Andy Chen over 6 years ago in reply to divyanshu bawa

TI__Mastermind 34745 points

Hi,

It's OK to use 0201 size device on Cff or feedback. Cff cap voltage rating should be >16V.

For LMR14020 design, pls change Cff cap from 270pF to 150pF, all other external components are OK.

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WEBENCH® Tools/LMR14006: Power Supply Design