The µPD4721 is a high-breakdown voltage silicon gate CMOS line driver/receiver based on the EIA/TIA-232-E standard. The internal DC/DC converter can switch between multiple voltages, realizing the allowing it to operate with a single +3.3 V or +5 V power supply. It also provides standby function.
This IC incorporates 2 driver circuits and 2 receiver circuits. An RS-232 interface circuit can be easily configured by connecting 5 capacitors externally.

FEATURES
• Conforms to EIA/TIA-232-E (former name, RS-232C) standards
• Selectable +3.3 V/+5 V single power supply (selected by VCHA pin)
• By setting the standby pin to a low level (standby mode), circuit current can be reduced. At such times, the driver output is in a high-impedance state.