max232 external capacitors

[patingin]

hi guys! does anyone know how to compute for the value of the external capacitors of max232? i know it is in the datasheet but how it was computed?

 

[Hero999]

It uses a circuit known as a charge pump to generate a higher voltage from the power supply.

The capacitor values depend on many factors, here's an article which discusses how to calculate them.
http://powerelectronics.com/passive_components_packaging_interconnects/capacitors/power_calculating_chargepump_circuits/

 

[Kevin Weddle]

The capacitors have to be able to deliver the required voltage to the load, which requires a capacitance that will charge to the voltage within the charge time and maintain the voltage until the next charging time.