GENERAL DESCRIPTION
Full operation requires only four external charge pump capacitors. In RS-485 mode the HALF/FULL pin configures the transceiver as either half or full duplex. All drivers can be slew limited to 250kbps in any mode to minimize electromagnetic interference (EMI) by setting the dedicated SLEW pin low. All transmitter outputs and receiver inputs feature robust electrostatic discharge (ESD) protection to ±15kV IEC 61000-4-2 Airgap, ±15kV Human Body Model (HBM) and ±8kV IEC 61000-4-2 Contact. 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 when in RS-232 mode. The RS-485/422 receiver inputs are high impedance (>96k), allowing up to 256 devices on a single communication bus (1/8th unit load). The SP330 operates from a single power supply, either 3.3V or 5V, with low idle current.
Exar Corporation
