Using AFE4490 with phototransistor

Mathieu Hingant

Other Parts Discussed in Thread: AFE4490SPO2EVM, AFE4490, AFE4400

Hello,

I am currently evaluating the AFE4490SPO2EVM and want to try it out with a phototransistor instead of a photodiode.

Does anybody could help me figure out how to connect a phototransistor to the INN and INP inputs of the AFE4490 chip? On the contrary of using a photodiode, it will require some additional components I believe but I am having some hard time figuring out what is required since I am not that familiar with phototransistor.

Thank you!

over 12 years ago

0 Kevin Wen over 12 years ago

TI__Intellectual 2235 points

Hi Hingant,

phototransistor and photodiode should have same working mechanism, but larger current. Would you mind to provide more information about the phototransistor you are using, like the datasheet? It will help to configure out whether additional components are needed or not.

Kevin

0 Mathieu Hingant over 12 years ago in reply to Kevin Wen

Prodigy 50 points

Hi Kevin,

The phototransistor I am trying to use is the following http://www.njr.com/products/press2013/NJL5501R.html.
Unfortunately I cannot seem to find the datasheet on internet. Which parameters are you interested in?

But if you say that the difference should only be having a larger current: does this means that you should just be able to connect his emitter and collector pins to INN and INP on the AFE4490? Or should it be connected in common-collector configuration for example?

Thanks