Exar offers the SP330 featuring a low-voltage logic interface
The SP330 is an advanced multiprotocol transceiver supporting RS-232, RS-485, and RS-422 serial standards and featuring a variable low voltage logic interface, down to 1.65 V. Full operation requires only four external charge pump capacitors. The RS-485/RS-232 mode pin selects RS-485 mode when high, and RS-232 mode when low. In RS-485 mode the HALF/FULL pin configures the transceiver as either half or full duplex. The high speed drivers operate up to 20 Mbps in RS-485/422 modes, and up to 1 Mbps in RS-232 mode. All drivers can be slew limited to 250 kbps 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 ±15 kV IEC 61000-4-2 Airgap, ±15 kV Human Body Model (HBM) and ±8 kV 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 SP330 operates from a single power supply, either 3.3 V or 5 V, with low idle current. The shutdown mode consumes less than 1 µA in low-power standby operation with RS-232 receivers enabled.