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Original question:

TPS7A85: Shottky Diode for reverse current protection

TPS7A85: Reverse Current Diode Selection

Eric Fu51
Prodigy 90 points
Part Number: TPS7A85

Hi,

I want to follow up on another thread:

[Resolved] TPS7A85: Shottky Diode for reverse current protection - Power management forum - Power management - TI E2E support forums

In the thread, it mentioned to size the diode to 1/2CV^2. I agree that this will be the power dissipated in the diode. My question is that the diode suggested has a forward voltage drop much larger than 0.3V (which is absolute max voltage difference between VIN and OUT (see below)). Wouldn't the IC be damaged? Shouldn't the diode be less than 0.3V? Thoughts?

  • 0
    TI__Mastermind 23361 points

    Hi Eric, 

    Having a diode with a small turn-on voltage is preferred. If the diode turn-on voltage is higher than internal ESD, it defeats the purpose of having the diode for protection. Depending on which IC you are looking at, the internal ESD voltage could change and maybe slightly higher than the 0.3V limit, so I would suggest having a diode with 0.3V turn-on voltage or less.

    Regards, 
    Jason Song