LM5060-Q1: Difference observed between calculated Idsth value and Practical measurement

Rajkumar Selvavinayagam

Part Number: LM5060-Q1
Other Parts Discussed in Thread: LM5060, TPS1663

Tool/software:

Hi,

As per the datasheet we have designed Idsth to 6.4A and it is verified in PSpice simulation

But in actual PCB the MOSFET switches OFF at 5.3A instead of 6.4A.

Please let me know why there is a difference.

Below are the calculations

Here is the schematics

Thanks,

Raj

0 Rakesh 11 months ago

Hi Raj,

LM5060 is not the right choice for accurate OCP. As you see in your calculation table, Idsth varies from 2.7A to 9.8A

Please go with TPS1663

BR,

Rakesh

0 Rajkumar Selvavinayagam 11 months ago in reply to Rakesh

Hi Rakesh,

Got it, Thanks for your immediate response.

But there is a wide variation between manual calculation and TI design calculator.

Want to confirm my calculations are correct?

Thanks,

Raj

0 Rakesh 11 months ago in reply to Rajkumar Selvavinayagam

can you share the filled up design calculator and your calculation sheet to check

0 Rajkumar Selvavinayagam 11 months ago in reply to Rakesh

Hi Rakesh,

I could provide only the screenshots for your reference.

VDSTH FORMULA =((O15*(O17-(O18/O19))+O16))/1000

IDSTH FORMULA =O20/O14

Thanks,

Raj

0 Rakesh 11 months ago in reply to Rajkumar Selvavinayagam

Please share source files.

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