GENERAL DESCRIPTION
Integrated cable termination and four configuration modes allow all three protocols to be used interchangeably over a single cable or connector with no additional switching components. Full operation requires only four external charge pump capacitors. A dedicated diagnostic loopback mode is also provided. The high speed drivers operate up to 20Mbps in RS485/422 modes, and up to 1Mbps in RS-232 mode. All drivers can be slew limited to 250kbps in any mode to minimize electromagnetic interference (EMI). All transmitter outputs and receiver inputs feature robust electrostatic discharge (ESD) protection to ±15kV IEC-61000-4-2 Air Gap, ±8kV IEC-61000-4-2 Contact, and ±15kV Human Body Model (HBM). Each receiver output has full fail-safe protection to avoid system lockup, oscillation, or indeterminate states by defaulting to logic-high output level when the inputs are open, shorted, or terminated but undriven. No external biasing resistors are required. The RS-232 receiver inputs include a 5k pull-down to ground.
Exar Corporation
