Exar introduces their low-power, 18 V-tolerant RS-485/RS-422 +3.3 V transceivers
The XR3070-78X family of high performance RS-485/422 devices is designed for improved performance in noisy industrial environments and increased tolerance to system faults. The analog bus pins can withstand direct shorts up to ±18 V, and are protected against ESD events up to ±15k V. The differential high-output driver delivers 10% higher SNR than standard RS-485/422 devices, affording additional noise margin or extended cable lengths. The receivers include full fail-safe circuitry, guaranteeing a logic-high receiver output when the receiver inputs are open, shorted, or undriven. The receiver input impedance is at minimum 96 kΩ (1/8 unit load), allowing up to 256 devices on the bus while preserving the full signal margin. The drivers are protected by short-circuit detection as well as thermal shutdown, and maintain high impedance in shutdown or when powered off. The XR3070-75X drivers are slew limited for reduced EMI and error-free communication over long or un-terminated data cables. The devices with DE and RE pins include hot swap circuitry to prevent false transitions on the bus during power-up or live insertion, and can enter a 1 nA low current shutdown mode for extreme power savings. The transceivers draw less than 600 μA from a +3.3 V supply, and typically only 300 μA when idling with the receivers active.