GENERAL DESCRIPTION
two shutdown modes and a diagnostic loop-back mode. Modes may be selected at any time by changing the logic state of the three MODE pins. The Exar charge pumps deliver true RS-232 driver output voltages from a single power supply at either 3.3V or 5V. The SP336E requires only four 0.1μF capacitors for charge pump. A slew rate control pin configures driver outputs for either high data rate or slew-controlled data rates. Slewcontrolled outputs minimize problems with reflections and ringing on long or un-terminated cables. All RS485 receivers or transceivers feature high impedance which allow up to 256 transceivers on a shared bus. When configured in RS-485/RS-422 mode, each driver may be individually enabled or put into tri-state, simplifying use on shared buses or bidirectional communication. All receivers have advanced failsafe protection to prevent oscillation when inputs are unconnected. In RS-232 mode each receiver input has a 5k ohm pull-down to ground. Differential Receivers will default to output logic 1 if inputs are floating, shorted or open but terminated.
Exar Corporation
