The ST3232BDR has two receivers and two drivers,  and a dual charge-pump circuit. The device meets the  requirements of TIA/EIA-232-F and provides the electrical  interface between an asynchronous communication controller and  the serial-port connector. The charge pump and four small external  capacitors allow operation from a single 3.0V to 5.5V supply.  The device operates at data signaling rates up to 250kbit/s and a  maximum of 35V/μs driver output slew rate.