TBU-CA065-200-WH_1111 Datasheet, PDF (1/2 Pages) Bourns Electronic Solutions – RS-485 Port Protection

RS-485 Port Protection
Evaluation Board 1
Introduction
This Evaluation Board serves as an aid in
evaluating circuit protection on RS-485
serial device ports, using two Bourns®
TBU® High-Speed Protectors (HSP), two
fast-acting GDTs and two TVS diodes to
meet the required industry standards on
RS-485 port interfaces. The recommended
Bourns® TBU® device solution, with a
low capacitance GDT, offers enhanced
high-speed performance features over
competing technologies, which can help
the design engineer increase the surge and
transient protection level on RS-485 ports
and place the entire circuit protection
solution into a smaller reduced PCB
area. Bourns has developed an RS-485
Evaluation Board (measuring 45 mm x
21 mm x 1.2 mm) manufactured using FR4
PCB with nickel gold plating on the top
and bottom sides.
1
IN1
1
GND
1
IN2
Figure 1
TBU® HSP 1
1
2
GDT1
TVS1
3
GDT3
GDT2
TVS2
1
2
TBU® HSP 2
RS-485 Evaluation Board Schematic
TVS3
1
3
2
2
3
1
TVS4
1
OUT1
TVS5
1
3
1
GND
2
1
OUT2
How to Connect the Evaluation
Board for Test Set-up
• Connect IN1 and IN2 to the
exposed lines.
• Connect OUT1 and OUT2 to the
RS-485 IC device.
* The default configuration of this board uses 2 GDTs
(GDT1, GDT2) and discrete SMB TVS diodes
(TVS1,TVS2). The board allows different configurations:
• 2 single 2031 GDTs (GDT1 and GDT2) may be
replaced by a dual 2030 GDT (GDT3, not yet released)
• 2 SMB TVS diodes (TVS1 and TVS2) may be
replaced with a) 2 SOT23 TVS diodes (TVS3, TVS4)
or b) a single TVS diode array (TVS5)
Figure 2 RS-485 Evaluation Board Top Side Layout*
Table 1
RS-485 Evaluation Board Bill of Materials
No. Part Number Qty.
Description
Reference
1 TBU-CA065-200-WH 2 TBU® Single Bidirectional Line 650 V 200 mA TBU® HSP 1, TBU® HSP 2
2 2031-23T-SM-RPLF 2
Single Line Fast-acting GDT 650 V
GDT1, GDT2
3
SMBJ12CA
2 Single Bidirectional Line TVS 12 V SMB
TVS1, TVS2
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