RS-232 interface IC for mixed-voltage serial links
The Texas Instruments MAX3232IDBG4 is a full-duplex RS-232 transceiver that handles the level translation between a UART's logic-level signals and the ±5V to ±15V swing required by the RS-232 bus.
The 3V to 5.5V supply range means this part works on a 3.3V rail without a separate 5V supply, simplifying the power tree on mixed-voltage boards. At 3.3V the charge-pump still generates the RS-232 bus voltages, so it is a drop-in for modern low-voltage designs. Receiver hysteresis is specified at 300 mV, which provides noise immunity on the incoming RS-232 lines without external schmitt-trigger buffers. That matters when the cable runs through a noisy electrical cabinet.
The base product number is MAX3232, which covers a family of pin-compatible options if you need a different package or temperature grade down the line.