50051R

Overview

The FTT-10A Free Topology Twisted Pair Transceiver, model 50051R, is a transformer-isolated communication module designed for LONWORKS networks. It supports differential Manchester coding at a transmission speed of 78 kbps over twisted pair wiring up to 500 meters in free topology or 2700 meters in doubly terminated bus topologies. The device automatically detects input clock frequencies of 5, 10, or 20 MHz and operates on a +5VDC supply with maximum currents of 5mA in receive mode and 20mA in transmit mode. Electrical isolation between the network and the device provides 1000Vrms protection for 60 seconds and 277Vrms continuous operation. The encapsulated plastic shell measures approximately 17.8mm by 7.2mm by 13.7mm.

Feature Summary

• Supports polarity insensitive free topology wiring including star, bus, and loop configurations
• Provides electrical isolation for grounded I/O devices within link power network segments
• Includes physical layer repeater functionality for expanding network distance and node count
• Compatible with Echelon's LPT-10 Link Power Transceiver for mixed segment interfacing

Applications

• LONWORKS control systems requiring transformer-isolated twisted pair communication
• Smart building automation and industrial IoT installations using BACnet or LON protocols
• Network expansion projects utilizing physical layer repeaters to extend wire distances
• Low profile applications such as DIN pack mounting where compact dimensions are required

Procurement Notes

Verify that the specific order corresponds to the RoHS compliant 50051R variant rather than the legacy leaded 50051 version. Confirm compatibility with the target Neuron Chip clock rates, as the transceiver does not support 1.25MHz or 2.5MHz operations. Ensure the application design accounts for the requirement of one terminator in free topology or two terminators in bus topology configurations.

Selection Notes

Select this component when designing LONWORKS nodes that require robust electrical isolation from the twisted pair network. It serves as a direct replacement for the older FTT-10 transceiver in most published applications, excluding repeater designs. Consider its automatic clock detection capabilities if the system utilizes varying Neuron Chip clock speeds. Verify that the operating temperature range of -40°C to +85°C meets the environmental requirements of the deployment site.

Part Context

This transceiver is part of the Echelon FTT-10A series, which facilitates the integration of LONWORKS technology into various control systems. The 50051R designation specifically identifies the RoHS compliant manufacturing version of the module. It is engineered to simplify installation by eliminating strict bus topology wiring constraints, thereby reducing system deployment time and costs.

Replacement Considerations

The FTT-10A (50051R) is the designated replacement for the FTT-10 transceiver. Note that some PC board modifications may be necessary due to mechanical differences between the two models. The FTT-10A does not support 1.25MHz or 2.5MHz Neuron Chip clock operations.