TBU-CA065-300-WH_11

RS-485 Port Protection Evaluation Board 2 Introduction This evaluation board serves as an aid in evaluating circuit protection on RS-485 serial device port solutions using Bourns® TBU® High-Speed Protector (HSP), MOV and TVS products 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 & transient protection level on RS-485 ports and place the entire circuit protection solution into a smaller PCB area. Bourns has developed a RS-485 evaluation board (measuring 50 mm x 25 mm x 1.2 mm) manufactured using FR4 PCB with nickel gold plating on top and bottom sides. 2 1 Line A Unprotected 1 40 mils trace 1 2 Protected 1 1 Load A II 2 1 J1 MOV1 2 GDT1 1 3 TBU® HSP 1 I 3 TVS1 2 TVS3 2 NU TVS5 3 TISP1 II J3 I 1 2 GDT3 2 2 2 2 II 3 I NU MOV2 1 1 2 GDT2 1 TBU® HSP 2 2 TVS2 1 TVS4 1 II I TISP2 1 2 J2 Line B Unprotected 40 mils trace Protected Load B J4 Figure 1 RS-485 Evaluation Board 2 Schematic How to Connect the Evaluation Board for Test Set-up • Connect J1 and J2 to the exposed lines. • Connect J3 and J4 to the RS-485 IC device. Figure 2 * In addition to the two TBU® HSPs, the default configuration of this board uses two MOVs (MOV1, MOV2) and a single TVS diode array (TVS5). The board allows different configurations: • 2 MOVs (MOV1 and MOV2) may be replaced by a) 2 single 2031 GDTs (GDT1 and GDT2) or b) a dual 2030 GDT (GDT3, not yet released) • 1 TVS diode array (TVS3) may be replaced with a) 2 SMB TVS diodes (TVS1, TVS2) or b) 2 SOT23 TVS diodes (TVS3, TVS4) or c) 2 SOT23-5 thyristor devices (TISP1, TISP2) RS-485 Evaluation Board 2 Top Side Layout* Table 1 RS-485 Evaluation Board 2 Bill of Materials No. 1 2 3 Part Number TBU-CA065-300-WH MOV-10D201K CDSOT23-SM712 Qty. 2 2 2 Description TBU® Single Bidirectional Line 650 V 300 mA Single Line 10 mm MOV 200 V Dual Bidirectional Line 7 V / 12 V Reference TBU® HSP 1, TBU® HSP 2 MOV1, MOV2 TVS5 11/11 • FU1107 RS-485 Port Protection Evaluation Board 2 Performance Graphs Run T T Trig? PreVu T T Trig? Ch1 Max 545 V 1 4 Ch1 Min -390 V Ch4 Max 11.3 mA Ch4 Min -2.55 A Ch1 500 V Ch4 5.00 A Ω M 10.0 ns T 20.40 % Ch1 Max 329 V 1 4 Ch1 Min -20.5 V Ch4 Max 1.98 A Ch4 Min -81.1 mA Ch1 200 V Ch4 1.00 A Ω M 400 ns T 31.60 % A Ch1 -380 V A Ch1 116 V Ch 1: input voltage / surge / fault to TBU® HSP Ch 4: TBU® HSP current The ohm unit following the current units shown for Channel 4 (i.e. AOhm) indicates that a 50 ohm termination was used internal to the oscilloscope Ch 1: input voltage / surge / fault to TBU® HSP Ch 4: TBU® HSP current The ohm unit following the current units shown for Channel 4 (i.e. AOhm) indicates that a 50 ohm termination was used internal to the oscilloscope Figure 3 ESD +8 KV Contact Discharge (IEC-61000-4-2) Figure 4 Surge 1.2/50 5 KV Run T T Trig’d Run T T Trig’d Ch1 Max 124.4 V 1 4 Ch4 Max 365.4 mA Ch4 Min -322.4 mA 1 4 Ch1 Max 28.3 V Ch4 Max 451.8 mA Ch4 Min -395.7 mA Ch1 100 V Ch4 200 mA Ω M 4.00 ms T 20.20 % A Line 116 V Ch1 20.0 V Ch4 200 mA Ω M 4.00 ms T 20.20 % A Line 116 V Ch 1: input voltage / surge / fault to TBU® HSP Ch 4: TBU® HSP current The ohm unit following the current units shown for Channel 4 (i.e. AOhm) indicates that a 50 ohm termination was used internal to the oscilloscope Ch 1: input voltage / surge / fault to TBU® HSP Ch 4: TBU® HSP current The ohm unit following the current units shown for Channel 4 (i.e. AOhm) indicates that a 50 ohm termination was used internal to the oscilloscope Figure 5 120 Vrms Figure 6 28 Vrms Reference For more information on implementing advanced circuit protection technologies for RS-485 ports, please review the Bourns RS-485 application note: http://www.bourns.com/data/global/pdfs/Bourns_RS-485_AppNote.pdf For further technical support and for complete circuit protection solutions, please visit www.bourns.com 11/11 • FU1107 “TBU” is a registered trademark of Bourns, Inc. in the U.S., Taiwan and European Community. “Bourns” is a registered trademark of Bourns, Inc. in the U.S. and other countries. COPYRIGHT© 2011 • BOURNS, INC. • 11/11 • e/FU1107