Inexpensive ESD-resistant 485 chips

[P. Short]

Does anyone have any suggestions for an ESD-resistant RS485 chip in a DIP8 package, particularly a low-power 5V version? The mouser parts that I've found so far (75LBC182) are pretty expensive ($2.40 in unit quantities).

[mrpackethead]

Im using the 75176's, but in a SOIC package.. I can't remember if there is a dip package, or what the esd specs are sorry.. but they are well under a $1.00 even in small qntys..

[P. Short]

Those aren't what I'm looking for...the basic 75176 draws large amounts of current (up to 70 mA in some versions, even when disabled), and are not characterized for any ESD resistance.

[RJ]

I was using these : ST485EBN

They are ESD resistant and allowed 256 recievers on a line (very low load on the buss) and that is the two reasons I used them. They appear to have stop making them and they are in short supply and the cost have skyrocketed.

If you move fast you can get some here but hang on to your wallet. They are expensive now. ;) like over $3!!!!

http://www.newark.com/89K1009/semiconductors-integrated-circuits/product.us0?sku=stmicroelectronics-st485ebn&_requestid=215164

I had to settle to move to the ST485BN which is not ESD resistant and only allows up to 64 transceivers on the bus. it is about $1.25 in quanitity.

I also would be interested in a ESD resistant cheap option that allows at least 64 devices on the bus.

RJ

[P. Short]

Thanks, RJ. I've used those parts in the past, and have a few left over. They cost $1.02 each when I bought 10 of them in July of 2006. Mouser has them labelled as obsolete, and the closest sub that I could find was the 75LBC182 that I mentioned above. I wonder why the availability has gone down (and hence the price goes up).

[RJ]

I believe because ST obsoleted them. I guess they were not selling. Well we know we used some but I just guess we are not a big enough bunch to keep them on the production line. LOL

I really worry more of the DIP stuff will go this way in the coming years. Might make it harder on the less techinical of us doing DIY.

[mrpackethead]

I really worry more of the DIP stuff will go this way in the coming years. Might make it harder on the less techinical of us doing DIY.

Nothing more a truer word than this.. Through hole stuff is destined for the museum. of course the coming years, also opens a world of new possibility's. You can run with it, or you can let it run you over. The best part is no-ones forcing you to do anything, its entirely your choice.

[mrpackethead]

Phil, are you looking for a RX/TX or just a RX device? I saw a technique used once that did'nt use a specific rs485 device, but used a differential amplifer, for a receiver.. Those can have extrememly low load on the line, and theres op-amps out there that use nearly zero power.. Not sure about the ESD..

Just chucking an idea out, that might work..

[mrpackethead]

Intersil ISL8483E

RS-485/RS-422 Transceivers, Esd Protected to 15kV, Half Duplex, 250kbps, Slew Rate Limited, 5V, With Rx/tx Enables And Low Power SHDN

Price comes down to ~$1.10 at 50up quantitys. And its still in a DIP package..

[P. Short]

It's a tempting part, even if it's not listed as ROHS compliant; the slew-rate limiting feature is nice. Where are you seeing those prices, though? The prices are much higher at mouser and digikey.

[scorpia]

Guys,

i had been doing a search on ebay, i come across the Sp485EE. seems to be reasonably cheap. not sure if its clear out stock or what but theres a few on there.

not sure if these are any good for what your after.

i got mine 20 for $9 delivered to aust.

you might need to search for SP485* oterhwise let me know if you cant find em and ill find an item number.

Peter