3peak Interface Chips

RS-485 supports multi-point (up to 32 nodes) half-duplex or full-duplex communication with differential signaling. RS-422 is point-to-point (1 driver, up to 10 receivers) full-duplex only. Both use differential signaling for noise immunity. RS-485 is more common for industrial networks, while RS-422 is used for longer point-to-point links. 3peak offers transceivers for both standards.

RS-485 for multi-node networks, RS-422 for point-to-point. Check specific product for half/full duplex support.

Standard RS-485 allows 32 unit loads (32 nodes with standard receivers). The TPT485 features 1/8 unit load receiver input impedance, allowing up to 256 transceivers on the same bus. For even larger networks, use repeaters to extend the bus. Each repeater creates a new bus segment supporting another 256 nodes.

256 nodes max with TPT485. Use repeaters for larger networks or longer distances.

Maximum cable length depends on data rate: At 100kbps: up to 1200m, At 1Mbps: up to 100m, At 10Mbps: up to 10m. Use twisted-pair cable (Cat5e or similar) for best noise immunity. Terminate both ends of the bus with 120Ω resistors. Use proper grounding to avoid ground loops. For longer distances, use repeaters or reduce data rate.

Shorter distance at higher speeds. Use twisted pair and proper termination.

Fail-safe ensures defined receiver output when the bus is idle, open, or shorted. Without fail-safe, noise can cause false triggering. TPT485 includes integrated fail-safe that forces receiver output high (logic 1) for: Open bus (no active driver), Shorted bus (A=B), Idle bus (no differential voltage). This eliminates the need for external biasing resistors.

TPT485 has internal fail-safe. No external biasing resistors needed.

The TPT485 features ±18kV HBM ESD protection on bus pins, sufficient for most applications. For additional protection in harsh environments: Use TVS diodes on bus lines, Add series resistors to limit current, Use isolated transceivers for high-voltage environments, Implement proper PCB layout with guard rings. 3peak also offers higher protection variants for extreme environments.

TPT485 has 18kV ESD protection built-in. Add TVS diodes for extreme environments.