The SN65C3222 and SN75C3222 consist of two line drivers, two line receivers, and a dual charge-pump circuit with ±15-kV ESD protection pin to pin (serial-port connection pins, including GND). The devices provide 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-V to 5.5-V supply. The devices operate at data signaling rates up to 1 Mbit/s and a driver output slew rate of 24 V/µs to 150 V/µs.
The SN65C3222 and SN75C3222 can be placed in the power-down mode by setting PWRDOWN\ low, which draws only 1 µA from the power supply. When the devices are powered down, the receivers remain active while the drivers are placed in the high-impedance state. Also, during power down, the onboard charge pump is disabled, V+ is lowered to VCC, and V is raised toward GND. Receiver outputs also can be placed in the high-impedance state by setting EN\ high.