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TVS intefering with rs232

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nsypid

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Hi iam using bidirectional TVS to protect rs232 line from overvoltage. the voltage breakdown is 16.7V. The problem is rs232 communication isn't working. When i desolder the TVS, the communication is working. Did i pick the wrong TVS ? iam using SMCJ15CA from bourns and the rs232 transceivers is max3232cdr.
 

Can you post the schematic that you have used.
 

I'm sorry, there might have been slight miscommunication with my friend. The problem is not with rs232 line but with 3.3V UART line. here is the schematic YS TVS Trouble.JPG
The TVS is written on the schematic. The line is directly connected to Freescale K60 microcontrollers.
 

Could be capacitance of TVS that is causing problems. SMCJ5.0 has around 5nF. Try to use SMAJ5.0 (1,5nF) or some low capaticance TVS (PESD5Z series,...). I think there is no need to use 1500W TVS on TTL line, could be something with lower power rating.
 

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