Replacing LM2595T-ADJ with LM2575T-ADJ

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#1
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Hallo there,

Does anybody knows to give me an answer?:

I have a pcb which I use to program PLDs, the problem is that for an unknown for me (at this time) reason the Vreg using an LM2595T-ADJ is damaged. The problem is that the LM2595T-ADJ has an internal short circuit. I have to fix the problem quickly because on Monday I have to send at my customer about 100pcs PLDs. I found in a drawer an LM2575T-ADJ.

The switcher input voltage is 20V, and the output I don't know because it's damaged now.

After reading the two datasheets I show that there is a diferance at the pins of the 2 chips (I can fix it), at the switching frequency, and at the suggested passive electronics.

So If I replace the 2595 with the 2575 (bewareing the pins), the Cs and L, without replacing R1 and R2 (used for adjusting the output voltage), will the circuit plays well. Is there something I miss? Is there something you suggest me?

Thank you very much, because it is very serious for me.

Michael.

User of:
IAR Embedded Workbench C/C++ Compiler
Altium Designer

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If you can verify the two resistor values that set the output of the regulator (between Gnd and output) you will know the final regulated output voltage.
Take a look at the data sheet page 11 for National's LM2595 this explains this resistive ratio quite well.

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Ok, thanks for your reply.

Michael.

User of:
IAR Embedded Workbench C/C++ Compiler
Altium Designer