Hello,
I'm using the LM22670 to charge two supercapacitors and after this supply a circuit (5V/1A).
I have almost 50 units working well, but 3 units got burn.
Below you can see the images of the 3 burned IC's:
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I'm using a 124k resistor to set the frequency to aprox. 300kHz and the SOA is above 35V. I'm using at the maximum 27V input to supply this circuit.
As you can see in the images, the pin 7 has disappeared, I couldn't find this lead, it can be vaporated itself?
In theese burned IC's the pins 8 and 6 are short circuited, The protection circuit and another componentes are intact.
The capacitors are directly connected in the output of switched inductor. The circuit charges two series supercapacitors (MAL222091001E3) to 5V.
My idea is use the protection against short circuit that limits the current to charge my supercapacitors.
My questions are the following:
1) My application of the LM22670 will have a high risk of failures when I'm producing 1000units of this circuit?
2) Why I got theese failures desbribed?
If needed more documents of this project, please tell me an email and I'll sent the project, because I can't publish here.
Thanks a lot.
