kenasw@btinternet.com wrote:
> I downloaded the datasheet for MAX232A (from farnell) and it seems
> that I need 5x0.1uF capacitors to make this chip happy. I was just
> wondering if I should choose electrolytic type capacitors or will
> anything do, since 0.1u is 100n, which is small even when it is not
> electrolytic.

Ceramics have much better characteristics, and at that capacitance and
voltage they are readily and cheaply available.  I don't know of any
electrolytic that is only 100nF, at least not in the 10s of volts range.

Even better, I would use 1uF ceramics.  These are now readily available and
about as cheap as 100nF.  Some of the MAX232 type chips work with 100nF, and
some require at least 1uF.  I haven't seen any variant that doesn't work
with 1uF.  This will also give you a stronger and cleaner + and - voltage
drive.

For example, I used 1uF ceramics on the RSLink RS-232 converter
(http://www.embedinc.com/products).  This allows using whatever the best
deal of the week is in MAX232 chips.  The current batch uses a TI chip,
which requires 1uF minimum if I remember right.


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