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LM5069: About the effect of SENSE pin on overcurrent detection

Kaji@PAN
Mastermind 7795 points
Part Number: LM5069

Hello,

I would like to ask you a question about LM5069-1.
I set the overcurrent detection constants below.
RSNS=18mΩ (variation 0.5%)
R1=47Ω (variation 1%)
R2=10Ω (variation 1%)
However, the datasheet states that 23uA is flowing through the SENSE pin, causing an offset across R2.
How should the influence of this 23uA be reflected in Rsns,eff in equation (3)?
Please tell me the calculation formula that reflects this.
Also, 23uA is TYP, but is there any information on MIN and MAX?

Best regards,

  • +1
    TI__Guru** 105361 points

    Hi Kaji,

    The 23uA of current causes a drop of 230uA (=0.23mV) across R2. The current limit threshold voltage VCL is 55 mV. So, 0.23mV drop causes just 0.4% accuracy impact on current limit threshold which is negligible. 

    Best Regards,

    Rakesh