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LT3045-1 Set Capacitor

Category: Hardware
Product Number: LT3045-1

Hi,

I am using the LT3045-1 to post-regulate the output of a switching regulator.

On page 18 and 19 of the datasheet of LT3045-1 I saw that using a ceramic capacitor at the SET pin can cause significant output noise due to piezoelectric response.

However, on LT3045-1’s DC2593A demo board, I saw that a ceramic capacitor is used at SET pin.

Is there a reason why ceramic capacitor is used here even though it causes high output noise?

When I check the tantalum capacitor alternatives, I saw that their life time is so short (1000 hours - 2000 hours).

The film capacitors are way too big compared to ceramic ones of the same capacitance.

And the electrolytic ones have high 1/f noise as stated on the LT3045-1 datasheet.

Do you think feedthrough capacitors could be a good alternative instead of these ones?

Thank you very much for your help.

Best regards.

  • Hello,

    This is only in the case of high vibration environment. The ceramic capacitor should stabilize voltage across the set pin. Snip below is from page 20 of the datasheet. Please refer. The demoboard is designed to utilize every function that the IC offers. If the ceramic capacitor is not needed, you can just remove it manually. It just gives the option on what to put in the demoboard that is essential to the design.

    Regards,
    Jhun