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Part Number: ISOW7842
On a couple of different designs we have trouble with the ISOW7842.The isolated voltage sometimes when starting up goes to 7V instead of the set 3.3V and the circuit get really hot.
Any idea what can cause this?
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In reply to Koteshwar Rao:
Here's a snap shot of the coupling.5V input, Load on 3.3V (iso side) is around 70mA.
At some point it looked as if we got less problem when we increased the slew rate on the power supply (supplying 5V) and we thought problem was solved but then it started to arise again (even with a slow power on ramp).
So currently we are clueless.
In reply to Per Bengtzohn:
We have tested with current limit set to 2A upto 20AWe have tested with slew rate of 20us/V downto (upto?) 20ms/VWe have also tested with more capacitance on input (5V side) upto 800µF
We haven't been able to see any correlations with these setups and the the latch-up problem.
When we get the problem (always from "cold-start") it usually there for a couple of restarts but when it starts to work its hard (impossible?) to get the fault back.
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