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LP8758-E0: LP8758-E0 : Is it possible to apply voltage distribution to the BUCK FB input at the default setting?

KANG KYU LEE
Prodigy 30 points
Part Number: LP8758-E0

Hello. I have a question.

The LP8758-E0 looks good for my FPGA power supply.

I need a total of four power rails : 1.2V, 1.8V, 2.5V, 3.3V.

But the LP8758-E0 is set to 1V, 1.2V, 1.8V, 2.5V.

The LP8758-E0 uses OTP, so the default power is determined unless I modify it.

I want to get the power I want when I turn it on.
But our company is so small that we don't need large quantity.
I haven't asked you, but I think it would be necessary to meet the minimum quantity to change OTP.

So I'm trying to change the voltage by hardware without any modification, so can I use the power feedback signal to divide the voltage?

According to the datasheet ... VOUT0: 1000mV.
If I design this as a circuit it looks like this ...

If I want to output 3.3V to VOUT0, can I change it as follows?

Then please check.
Thanks.

KYU.

  • 0
    TI__Mastermind 39031 points

    Hi, KYU,

      It's not recommended to use external resistors divider to change its output voltage, since the feedback pins FB_Bx of the device to the respective sense pins on the load. The sense lines are very susceptible to noise. They must be kept away from noisy signals such as PGND_Bxx, VIN_Bx, and SW_Bx, as well as high bandwidth signals such as the I2C. To avoid both capacities as well as inductive coupling; it's necessary to keep the sense lines short and direct and run the lines in a quiet layer; If possible, isolate them from noisy signals by a voltage or ground plane.