LM25066: asked recommendation in layout for 4 Rsense

Tim Lu

Part Number: LM25066

Dear Sir:

I have read https://e2e.ti.com/blogs_/b/powerhouse/archive/2014/10/30/choosing-the-right-sense-resistor-layout but it does not mention what I want. Please give me some advise.

Below is a part of circuit. Because of Power dissipation ,we parallel 4 Rsense in application.

And layout will be as below (yellow lines are sense wire+- for R sense)

Because the limit in space.

1.Can all the sense+ wire connect together and sense- wire connect together too,and do not effect to hotswap's current sense and current limit?

2.Or can I put more RCL1 ,RCL2 ( in circuit is PR9,10) ,a pair per short pin for convenience in layout?

sincerely

Tim

over 3 years ago

0 Praveen GD over 3 years ago

TI__Guru 57737 points

Hi Tim,

We recommend you to follow kelvin connections for current sense lines SNS+ and SNS-

Yes you have to connect all the positive Sense lines and all the negative lines respectively as shown below

Please follow layout guide lines at the end of datasheet.

0 6351228 over 3 years ago in reply to Praveen GD

Prodigy 70 points

Hi guys,

If we use 4pcs or more shunt resistor for LM25066 current sense, will you suggest to draw 1 short pin near per shunt resistor to reduce ESL, total 4pcs or more?

Thanks.

Maguire

0 Praveen GD over 3 years ago in reply to 6351228

TI__Guru 57737 points

Hi Maguire,

Can you please share any graphical representation of how you plan to implement the current sense ? It would help me understand your question more clearly.

0 6351228 over 3 years ago in reply to Praveen GD

Prodigy 70 points

Hi,

Please see the following picture.

0 Praveen GD over 3 years ago in reply to 6351228

TI__Guru 57737 points

Hi Maguire,

I have asked for a graphic of your intended layout because I wanted to understand your below explanation and question more clearly. Can you also elaborate your below statement ?

'If we use 4pcs or more shunt resistor for LM25066 current sense, will you suggest to draw 1 short pin near per shunt resistor to reduce ESL, total 4pcs or more?'

0 6351228 over 3 years ago in reply to Praveen GD

Prodigy 70 points

Hi Praveen,

Sorry, should be 4 pair short pin, not 4pcs short pin.

There are 4 pair short pin for 4 current sense resistors, respectively.

The layout is as the following picture.

Please review and comment kindly.

0 6351228 over 3 years ago in reply to 6351228

Prodigy 70 points

0 6351228 over 3 years ago in reply to 6351228

Prodigy 70 points

0 Praveen GD over 3 years ago in reply to 6351228

TI__Guru 57737 points

Hi Maguire,

The layout of current sensing looks good to me. You have followed proper Kelvin sensing connections.

By the way, I am not very aware of the SHORTPIN used in your schematic. Looks like the two pins of the SHORTPIN have the same potential and so you are using to to tap the signal from the sense resistor.

Do you have any other questions. If not, can we close this thread?

0 6351228 over 3 years ago in reply to Praveen GD

Prodigy 70 points

Thanks, Praveen.

The SHORTPIN have a shape in manufacture layer, and the shape can short two pin of SHORTPIN. Do not worry about it.

I do not have any question.

Please close the thread. Thanks.

0 6351228 over 3 years ago in reply to 6351228

Prodigy 70 points

Where is "This resolved my issue" bottom?

Thanks.

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LM25066: asked recommendation in layout for 4 Rsense