udhay_cit
Full Member level 6
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I'm designing a RS-485 communication device for CE & UL standard certifications. My test standard is ±2KV (IEC61000-4-5). We have In-house lab test facility with ESD, EFT, Signal line surge generator, etc., For my various protection circuit, I can't able to pass the test more then ±1.5KV. Please review my circuit & share your commands.
The attached waveforms & test run procedures are below..,
2kv_sig_pos (2kv signal surge positive)
04.gdt_bu_2k (bourns GDT parallel with surge generator)[measured across A & GND point]
05.gdt_bk_2k (brightkings GDT parallel with surge generator)[measured across A & GND point]
06.gdt_bu_tvs_2kv1 (bourns GDT & SMAJ6.5CA TVS diode parallel with surge generator)[measured across A & GND point]
07.gdt_bk_tvs_2kv1 (brightkings GDT & SMAJ6.5CA TVS diode parallel with surge generator)[measured across A & GND point]
08.gdt_bk_tvs_2kv_ab (brightkings GDT & SMAJ6.5CA TVS diode parallel with surge generator)[measured across A & B point (differential)]
09.gdt_bk_res_tvs_2kv_ab (brightkings GDT, 10ohms resistor(between GDT & TVS) SMAJ6.5CA TVS diode parallel with surge generator)[measured across A & B point (differential)]
As per bourns "RS-485 PORT PROTECTION EVALUATION BOARD1" design notes, I changed my design as GDT, TBU(series), TVS. But this configuration also doesn't help me. The waveform similar to GDT+Resistor+TVS configuration.
Measurement tools are,
Oscilloscope (Agilent DSO-X 3014A, 100MHz)
Active differential probe (Pintek DP-150 PRO)
Surge generator (EMC Partner TRANSIENT 3000)
RS-485 Transceiver (MAX485)
GDT ( Bourns 2030-23T & brightking 2RL230M-6)
TVS (Vishay SMAJ6.5CA)
Regards
Udhay
The attached waveforms & test run procedures are below..,
2kv_sig_pos (2kv signal surge positive)
04.gdt_bu_2k (bourns GDT parallel with surge generator)[measured across A & GND point]
05.gdt_bk_2k (brightkings GDT parallel with surge generator)[measured across A & GND point]
06.gdt_bu_tvs_2kv1 (bourns GDT & SMAJ6.5CA TVS diode parallel with surge generator)[measured across A & GND point]
07.gdt_bk_tvs_2kv1 (brightkings GDT & SMAJ6.5CA TVS diode parallel with surge generator)[measured across A & GND point]
08.gdt_bk_tvs_2kv_ab (brightkings GDT & SMAJ6.5CA TVS diode parallel with surge generator)[measured across A & B point (differential)]
09.gdt_bk_res_tvs_2kv_ab (brightkings GDT, 10ohms resistor(between GDT & TVS) SMAJ6.5CA TVS diode parallel with surge generator)[measured across A & B point (differential)]
As per bourns "RS-485 PORT PROTECTION EVALUATION BOARD1" design notes, I changed my design as GDT, TBU(series), TVS. But this configuration also doesn't help me. The waveform similar to GDT+Resistor+TVS configuration.
Measurement tools are,
Oscilloscope (Agilent DSO-X 3014A, 100MHz)
Active differential probe (Pintek DP-150 PRO)
Surge generator (EMC Partner TRANSIENT 3000)
RS-485 Transceiver (MAX485)
GDT ( Bourns 2030-23T & brightking 2RL230M-6)
TVS (Vishay SMAJ6.5CA)
Regards
Udhay
Attachments
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2kv_sig_pos.png21.1 KB · Views: 248
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04.gdt_bu_2kv.png22.3 KB · Views: 221
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05.gdt_bk_2kv.png23.2 KB · Views: 202
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06.gdt_bu_tvs_2kv1.png24 KB · Views: 192
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07.gdt_bk_tvs_2kv.png24.1 KB · Views: 221
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08.gdt_bk_tvs_2kv_ab.png22.2 KB · Views: 204
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09.gdt_bk_res_tvs_2kv_ab.png23.7 KB · Views: 395
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Bourns_FU1106_RS-485_Evalboard_DesignNote_1.pdf392.5 KB · Views: 142
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2R-6-SERIES_141202.pdf204.4 KB · Views: 155
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2030-xxT-SM.pdf317 KB · Views: 165
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MODBUS.PNG64.8 KB · Views: 2,944
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20151001_185916.jpg576.3 KB · Views: 506