Alan B. Pearce wrote:
>>I also dont under stand the caps, they call for 1uF for the 232
>>and .1uF for the 232A. One would think there would be a range of
>>cap values, perhaps with a tradeoff curve to indicate maybe less
>>ouput drive capability or something. They sure seem to have
>>minimalist data sheets :)
>
>Not quite what I was on about. If you check the 3232 data sheet you will find
>that different caps are specified for single voltage working, and variable
>voltage working. For variable voltage one cap is 0.1uF min, and the other three
>are 0.47uF min. For operating at fixed 3 Volt, all caps are 0.1uF min. For 5
>volt fixed supply, one cap is 0.047uF minimum, and the other three are 0.33uF
>min. Go figure - but the way I read the data sheet, it only guarantees to swing
>the output +/-6 Volts.
>

AFAIK, the "minimum" cap sizes usable are mainly determined by the
channel resistance of the switches and probably more importantly, the
frequency of the internal oscillator. If you measure it, the 232A,
using .1 uF caps, probably runs much faster than 232, using 1 uF.
I can't comment about the cap selection described above [???]

Also, these devices are simply voltage "doublers", so 5v --> +/-10v
and 3v --> +/-6v.

Lastly, larger caps will help prevent output droop. Especially,
if you try to suck some juice out of these things to run some
peripheral analog cktry, the voltage will droop considerably as
the load is increased. The older 232 is maybe a little better for
this. Neither is very good for this.

- DanM