XR3070-78X Series of High-Performance RS-485/422 Devices


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.

Features and Benefits
  • 10% higher SNR (Signal-to-Noise Ratio) compared to other RS-485 devices (1.65 V vs. 1.5 V)
  • ±18 V fault tolerance on analog bus pins
  • Enhanced receiver fail-safe protection for open, shorted, or terminated but idle data lines
  • Hot-swap glitch protection on DE and RE pins
  • Driver short-circuit current limit and thermal shutdown for overload protection
  • 1/8 unit load allows up to 256 devices on bus
  • Robust ESD (Electrostatic discharge) protection: ±15k V IEC 61000-4-2 air gap discharge, ± 8k V IEC 61000-4-2 contact discharge, ±15k V human body model, ± 4k V human body model on non-bus pins, +3.0 V to +3.6 V operation (3.3 V ± 10%) and 300 μA idle current, 1 nA shutdown current

XR3070-78X Series

Manufacturer Part Number Description Available Quantity Datasheets
XR3070XID-F IC TXRX RS485/422 250KBPS 14SOIC 196
XR3071XID-F IC TXRX RS485/422 250KBPS 8SOIC 196
XR3072XID-F IC TXRX RS485/422 250KBPS 8SOIC 147
XR3073XID-F IC TXRX RS485/422 1MBPS 14SOIC 196
XR3074XID-F IC TXRX RS485/422 1MBPS 8SOIC 186
XR3075XID-F IC TXRX RS485/422 1MBPS 8SOIC 196
XR3076XID-F IC TXRX RS485/422 20MBPS 14SOIC 196
XR3077XID-F IC TXRX RS485/422 20MBPS 8SOIC 196
XR3078XID-F IC TXRX RS485/422 20MBPS 8SOIC 196