Exar SP3221E Intelligent RS-232 Transceiver is intended for portable or battery-powered applications such as embedded computers, data logging devices, medical diagnostics, and remote sensors. This Exar device uses an internal high-efficiency, charge-pump power supply that requires only four 0.1µA capacitors. This charge pump and Exar's driver architecture allow the SP3221E to deliver compliant RS-232 performance from a single power supply ranging from +3.0V to +5.5V. The AUTO ON-LINE® feature allows the device to automatically "wake-up" during a shutdown state when an RS-232 cable is connected and a connected peripheral is turned on. Otherwise, the device automatically shuts itself down, drawing less than 1µA.