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I'm going to make a PIC programmer, so currently I'm acquiring parts that I'll need. And here's the one part that I can't get:

C2 - 22uF / 16V tantalum or 47uf / 6.3V tantalum
This is a high speed capacitor and should be a tantalum type.

That's what it says in the tutorial.

So my question is: Can I replace this tantalum capacitor with \$22\mu F\$ / higher voltage or \$47\mu F/ 10V\$ or something like this? I'm confused because in tutorial they are using \$47\mu F/6.3V\$ as replacement ...

How do I know how many farads I need ?

Thanks

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I would guess that \$22\mu F\$ is the minimum capacitance that the application can use.

Part characteristics can differ as their voltage rating increases, so be careful not to go 'too' high. (Don't put a 100V capacitor where there once was a 16V part). I would wager that if you can get something between \$22 \mu F\$ and \$47 \mu F\$ in 25V, you'll be fine.

You may also be able to use multilayer ceramic capacitors in parallel to get \$ 22\mu F\$ - just don't use electrolytic. Electrolytic capacitors are not 'high speed' due to their intrinsic parasitic characteristics.

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  • \$\begingroup\$ I have good news for you, even 100uF ceramics is not hard to get nowadays :-) So no longer need to parallel. Also, if one use ceramic instead of tantalum, it's generally safe use lower value (like 10uF), but one need to check datasheet. \$\endgroup\$
    – BarsMonster
    Jul 15, 2011 at 14:46
  • \$\begingroup\$ True, but soldering those huge-value ceramic capacitors is a problematic operation. Bad thermal management of the assembly process and board flex can easily break them, leaving you with a non-fusible heat source on your board (usually connected to a power supply rail) which can make a nice fire. Hand-soldering? Forgetaboutit... \$\endgroup\$
    – Adam Lawrence
    Jul 15, 2011 at 16:21
  • \$\begingroup\$ Cannot confirm your bad experience - I handsoldered like 50 of 22 & several 66 uF ceramic caps (1206 case, bigger for 66), and none of them was damaged. I solder at 250C. \$\endgroup\$
    – BarsMonster
    Jul 15, 2011 at 17:45
  • \$\begingroup\$ Consider yourself fortunate. \$\endgroup\$
    – Adam Lawrence
    Jul 15, 2011 at 18:22
  • \$\begingroup\$ Thank you for you answer. I'll look in my local store for capacitor between 22μF and 47μF and the closest to 16V. If I can't find it, I'll use ceramic ones ;) Just one question: are multilayer ceramic capacitors subgroup of ceramic ones, or are all ceramic capacitors multilayer ? \$\endgroup\$
    – xx77aBs
    Jul 16, 2011 at 12:23

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