It handles serial communication at 250 kbps, which is adequate for legacy UART links, terminal interfaces, and industrial control panels that don't need the higher rates of newer transceivers.
Supply voltage and 3.3 V compatibility
At 3.3 V the transceiver meets RS-232 output levels without a charge pump boost issue — the internal charge pump generates the necessary ±5.5 V swing from the single supply. This makes the MAX3222CDBRE4 a direct fit for 3.3 V MCU UARTs that need to talk to legacy DB9 ports or industrial equipment still running ±12 V signaling.
Receiver hysteresis and noise margin
The 300 mV receiver hysteresis provides built-in noise rejection on the incoming RS-232 lines. In a factory floor or motor-drive environment where cable runs pick up common-mode noise, that hysteresis prevents the receiver from chattering on a marginal signal.