Go Down

Topic: High Speed optocoupler (Read 1 time) previous topic - next topic

Tom30

Sep 05, 2014, 12:14 pm Last Edit: Sep 05, 2014, 02:47 pm by Tom30 Reason: 1
Hi,
I like to galvanic isolate a rs485 shield from an Arduino.
There for I need 3 optocoupler in between the TX RX and Ctrl line
Can someone recommend me a common fast optocoupler  ?

Appreciate in advance the answer,

Tom

CrossRoads

Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

Pelleplutt

Could you use ADM2482 or similar.
6,5to 9.5$ at DigiKey, as always cheaper from China

Pelle

CrossRoads

Seems kind of pricey. For $3.30 you can have a 30nS delay part.
TLP117(F)
http://www.digikey.com/product-detail/en/TLP117(F)/TLP117(F)-ND/2178278

15nS, 30nS, either way is <1 clock cycle delay.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

Pelleplutt

<<There for I need 3 optocoupler in between the TX RX and Ctrl line>>

Well, 3x 3.33$ + some parts around.

Pelle

CrossRoads

That's a valid way to look at it also.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

Pelleplutt


mart256

#7
Sep 05, 2014, 06:40 pm Last Edit: Sep 05, 2014, 06:52 pm by mart256 Reason: 1
Triple channel Isolator for Tx-Rx lines for 4 USD.
ISO7321 is for bidirectional communication, although Ctrl line goes only in one direction (I suppose you need from master to slaves, then that should work).
Lines A and C for bidirectional communication, line B for Ctrl line.

Datasheet http://www.ti.com/lit/ds/symlink/iso7231c.pdf

Piece http://www.digikey.com/product-detail/en/ISO7231CDW/296-22960-5-ND/1770136

CrossRoads

That looks like a great part. Too bad it's SMD only, need a DIP adapter to play with it on a protoboard.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

Go Up