Linear Opto Isolator

[pikstart]

Hi! I am looking for a linear opto isolator chip with at least 4 channels.

I know the IL300, HCNR200 and the like but as my project involves 8 analog inputs to a PIC mcu, my main concern is to make the analog front end as compact as possible. Making 8 circuits based on the above chips will be bulky and costly. Are there other alternatives?

Thanks for reading and perhaps replying.

Ioannis

 

[crutschow]

It would help if we new what type of circuit this is and what type of isolation you need.

 

[Mikebits]

If a linear opto chip is your requirement, I think the best you can hope for is a dual channel.

http://www.clare.com/home/pdfs.nsf/www/LOC210_R4_0.pdf/$file/LOC210_R4_0.pdf

Not sure why the link is not clickable ?

 

[dknguyen]

HCPL-7800 and HCPL-7800A are the only "self-contained" analog isolators I have found.

 

[pikstart]

Thanks for the replies. Please have a look at this link:
**broken link removed**

I wish it could be more clear to see the opto chips. That is what I need!

My project is defferent though. I have sensors (0-10 and 4-20mA) that are in a water pump station and want to read the values and send them over a radio modem to the main console station. I prefer the sensors are galvanic isolated.

I have in mind the chips proposed here, but the above link I think rules in matter of size and maybe cost.

Thanks again,
Ioannis

 

[Ubergeek63]

why not just change it to a PWM and isolate that? it is expensive to get good linear isolation, but then I am usually looking for 5KV+ isolation.

it is really easy since you are reading it with a micro anyhow. just send a fixed frequency ramp into one input of a comparator and your unknown into the other and feed that into a transmitter (there are some links that will take that directly). If you absolutely must, use a 555 for the ramp and use the micro to take out the RC nonlinearity.

 

[jbeng]

You didn't say what kind of freq response you need, so I presume it's pretty lo freq or DC. If so, you might be able to use these Vactrols ... **broken link removed**

You can get them here ... <Newark Electronics>

Jeff

 

[pikstart]

Thanks for the ideas. I will check them. I liked the vactrols very much. Are they available in Europe?

Ioannis

 

[audioguru]

Newark is American but was purchased by Farnell of Europe. Farnell is in many countries. Go to their website and click on the flag of your country.

 

[pikstart]

Thank you uncle $crooge!

Ioannis