subsitute capacitors in charge pump?

[justDIY]

I'm drawing up a circuit using the LM2682 doubling inverter, and the datasheet shows using 3.3uF solid tant capacitors, which are polarized.

The vendor I like to buy from is kinda pricey on solid tant and I already have 4.7uf ceramics on order for another project, so I was hoping I could use those? The datasheet claims larger caps are fine, the caveat is increased design space and cost, with the benefit being lower ripple and internal resistance.

My question; I know it's not good to put polarized caps in where non-polar is specified, but is the reverse also true?

 

[RadioRon]

Usually going the other way is fine. The bigger issue that you sometimes come across is ESR, and in some other cases capacitance that varies with voltage, such as in some ceramics. I don't see any big problems with going with ceramic in your charge pump. Obviously there will be differences in breakdown behavior at their limit voltages between ceramic and tantalum and I'm not expert on all those, but if you are working well within the limits of the part you choose, the ceramic is typically going to have a lower ESR which should be a bit better for your application. Shouldn't it? Another area to watch for is piezo microphonic effects in ceramic but that's only a big deal in the most extremely sensitive audio circuits or in loop filters for synthesizers.