MPM3683-7 current limiting

I’m looking at the Over-Current Protection section of the datasheet, and it gives both a formula for computing Rcs and a table of Rcs values for typical applications (Table 2). However, plugging in the numbers from the table into the formula doesn’t give the same results that are listed in the table. For example, if I use the values in the third row of the table (Vin=12V, Vout=1.8V, Rcs=16.2k, Fs=1MHz), I end up with a current limit of 10.8A instead of 10. Using the formula, I find I’d need Rcs=20.9k (round to 21k if we’re using standard 1% values) in order to get a current limit of 10A, instead of the 16.2k that the table suggests.

My guess is that there’s either an error in one of the given parameters (e.g. Vocp, Gcs) or the values in the table were computed incorrectly. I’d appreciate it if anyone can shed some light on this.

Hello Stephen.harvey.

I will look into this and get back to you as soon as possible.

Thank you,
Vinh Tran

Hello Stephen.harvey.

The value you have solved for is correct. However, the table on the DS is what is seen in internal testing to work best for those typical application values. The equation will help you get close to the limit.

Thank you,
Vinh Tran

Thanks for the response. So if I’m understanding correctly, the equation is an approximation, and the only way to get exact values is through testing?