RS-485 Surge Protection , any as SM712?

[carpenter]

I need cheaply solve surge protection RS-485.
My first idea will use 2x 200V varistor + 2x TBU-CA065-300-WH + SM712
see https://www.bourns.com/data/global/pdfs/Bourns_RS-485_Serial_PortNote.pdf#search="0038194856

unfortunately product of bourns is expensive
https://de.farnell.com/bourns/tbu-c...bu-650v-450ma/dp/1833394?Ntt=TBU-CA065-300-WH
https://de.farnell.com/semtech/sm712/diode-tvs-asy-rs485-7-12v-sot23/dp/2059024

Can you advise a cheaper alternative?
First of all, I wonder whether it is to get something like SM712 and SM712 itself cheaper than Farnell

 

[schmitt trigger]

Littelfuse also has a very extensive line of protectors, including varistors, TVS and Sidactors.

https://www.littelfuse.com/

 

[dick_freebird]

Your alternatives and expense depend on just what kind
of "surge" you're needing to suppress, and to what clipped
level. Overkill = over$. Underkill = field failure ($ later).
Do you have an actual I, V, t understanding of the threat
sufficient to do component selection?

 

[ArticCynda]

Littelfuse also has a very extensive line of protectors, including varistors, TVS and Sidactors.

https://www.littelfuse.com/

They do provide free samples though: https://www.littelfuse.com/order-sample.aspx

 

[schmitt trigger]

Your alternatives and expense depend on just what kind
of "surge" you're needing to suppress, and to what clipped
level. Overkill = over$. Underkill = field failure ($ later).
Do you have an actual I, V, t understanding of the threat
sufficient to do component selection?

Well put Dick.

Transient (surge) protection is both black magic and science.
The engineer who can really understand it and design the correct surge protection for the actual application and electrical environmental conditions, is worth his weight in gold.

 

[ArticCynda]

Transient (surge) protection is both black magic and science.
The engineer who can really understand it and design the correct surge protection for the actual application and electrical environmental conditions, is worth his weight in gold.

Can you recommend good literature on this topic?

 

[schmitt trigger]

The IEEE has a lot of excellent standards, start here:

https://www.techstreet.com/searches...18944&sort_direction=&sort_order=&per_page=50

They are not free, however.

 

[bking]

Some other info:
https://www.mouser.com/catalog/specsheets/bourns2030.pdf
https://www.analog.com/static/imported-files/circuit_notes/CN0313.pdf
**broken link removed**

And an older thread from here:
https://www.edaboard.com/threads/204010/

 

[grittinjames]

You can use a small value polyfuse and a TVS,
Also will get some idea from below TI s aplication notes\
https://www.ti.com/lit/an/slla292a/slla292a.pdf