RS-485EVALBOARD3

RS-485 Port Protection Evaluation Board 3 Introduction This evaluation board serves as an aid in evaluating circuit protection on RS-485 serial device port solutions using Bourns® TBU® High-Speed Protectors (HSPs), FLAT® Gas Discharge Tube (GDT) Surge Arrestors and Transient Voltage Suppressor (TVS) products designed to meet the required industry standards on RS-485 port interfaces. The recommended Bourns® TBU® HSP solution offers enhanced performance features over competing technologies, which can help the design engineer to increase the surge and transient protection level on RS-485 ports, placing the entire circuit protection solution into a smaller PCB area. Bourns has developed an RS-485 evaluation board (measuring 53.5 mm x 25.3 mm x 0.85 mm) manufactured using an FR4 PCB with nickel gold plating on the top and bottom sides. J1 J2 GND GND MOV1 A GDT1 GDT3 TISP1 TBU® HSP 1 TVS1 GDT5 B MOV2 TVS2 GDT2 GDT4 TISP2 A TVS3 B TBU® HSP 2 GND GND Figure 1 RS-485 Evaluation Board 3 Schematic Figure 2 RS-485 Evaluation Board 3 Top Side Layout* Table 1 RS-485 Evaluation Board 3 Bill of Materials How to Connect the Evaluation Board for Test Set-up • Connect J1A and J1B to the exposed lines. • Connect J2A and J2B to the RS-485 IC device. *The default configuration of this board uses two GDTs w/ FLAT® technology (GDT3 and GDT4) and one TVS diode (TVS3). The board allows different configurations: • Two Model 2017 GDTs w/FLAT® technology (GDT3 and GDT4) may be replaced by a) two MOVs (MOV1 and MOV2) or b) two Model 2031 GDTs (GDT1 and GDT2) or c) two SMD package TISP® devices (TISP1 and TISP2) or d) a dual line Model 2030 GDT (GDT5). • One SOT23 TVS diode (TVS3) may be replaced with two SMB TVS diodes (TVS1, TVS2). No. Part Number Qty. Description Reference 1 TBU-CA085-300-WH 2 TBU® Single Bidirectional Line 850 V 300 mA TBU® HSP 1, TBU® HSP 2 2 2017-09-SMH-RPLF 2 GDT w/FLAT® Technology 90 V GDT3, GDT4 3 CDSOT23-SM712 1 Dual Bidirectional Line TVS 12 V SOT23 TVS1, TVS2 9/17 • K1701 RS-485 Port Protection Evaluation Board 3 Performance Graphs RS-485 Port Protection Evaluation Board 3 80 Ω TBU-CA085-300-WH Line 1 CDSOT23-SM712 RS-485 Interface 2017-09-SMH-RPLF 2017-09-SMH-RPLF 80 Ω TBU-CA085-300-WH Line 2 Surge Generator 1.2/50 µs, 2 kV Figure 3 RS-485 Port Protection Reference For more information on implementing advanced circuit protection technologies for RS-485 ports, please review Bourns’ RS-485 Protection Solution: http://www.bourns.com/rs485 For further technical support and for complete circuit protection solutions, please visit www.bourns.com Figure 4 Surge Test 2 kV (1.2/50 µs, REXT = 80 Ohms) COPYRIGHT© 2017 • BOURNS, INC. • 9/17 • e/K1701 “TBU” is a registered trademark of Bourns, Inc. in the U.S. and other countries, except Japan. All references to TBU® in this document for use in Japan shall be deemed to be replaced with Bourns® TBU™. “Bourns” and “FLAT” are registered trademarks of Bourns, Inc. in the U.S. and other countries. 9/17 • K1701