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LM5069: Part not latching off as intended

Part Number: LM5069

I'm using LM5069-1 in a design of mine. When testing out a dead short on the output, the part correctly detects a short circuit and turns off the mosfet. After waiting the typical insertion delay time of 11ms, the part then restarts itself. I have verified that i'm using the correct part (IC package has SNAB on it). I read from other posts that if the OUT pin on the LM5069 goes below -1V, it can reset the part. So I tried placing replacing my TVS SMAJ58A with schottky diode SL310A-TP on the output, but it can't clamp the voltage to -1V (it looks like it's at -5V). 

1) Can this part be used for 25A loads? It seems that even for schottky diodes, the forward voltage will likely exceed 1V when its forward current is 25A (50-100A when the circuit breaker or short circuit protection is engaged). Are there other ways to avoid having the VOUT pin go below -1V other than the schottky diode method?

2) Is there something else wrong with my implementation that would cause the part to restart itself even though it should latch off? 

Below is my schematic. I am using the UVLO pin as an EN signal.

Test with the schottky diode:

Zoomed in on short circuit trip. Note that the source voltage clamps at about -5V.

  • I wanted to add one more image from the testing. This is zoomed in when the LM5069 restarts and tries to turn the mosfet on. It ultimately fails as a short (as seen by the gate and source voltages tracking one another).

  • Hi Brandon,

    Sorry for the delay.

    LM5069 can be used in 25 A applications.

    You can use this additional Schottky diode and a resistance to limit the negative voltage at the OUT pin during short-circuit. This may help in entering into the insertion delay. 

    Schematic looks fine. Please add this above circuit.

    Please note that the latch-off part will retry for one time after the short-circuit fault. This is an expected behavior. Please refer to the below screenshots. 

    Please click on "This resolved my issue" if this post answers your query.