Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

Optocoupler "dark current" increases with age or temperarature?

Status
Not open for further replies.
T

treez

Guest
Hello,
Does the “dark current” of the TCLT1003 optocoupler increase as the opto ages or gets hot?…if so, by how much? (the datasheet doesn’t say)

TCLT 1003 datasheet
https://www.vishay.com/docs/83515/tclt1000.pdf

We are using the opto with the opto-transistor in common emitter connection, and it acts as a switch to turn ON/OFF a PFET……We are worried that if there is leakage current (dark current) going through the transistor when it should be off, then our PFET will get turned ON when it should not be ON.
 

Optocouplers are very sensitive to temperature. With the one you use you need to increase the LED current as high as you can and put low emitter resistor. You select the value by the gain of the optocoupler.
The safer way is to use optocoupler with outside connection to the transistor base. Connect the base to ground via 100K or other value that cancels the leakage current of the transistor, this way you can save current on the LED.
 
  • Like
Reactions: treez

    T

    Points: 2
    Helpful Answer Positive Rating
ok thanks, I know they are very temperature sensitive, but is the dark current temp. sensitive?
 

Look at fig 9 on the datasheet, it will tell you how much.
 
  • Like
Reactions: treez

    T

    Points: 2
    Helpful Answer Positive Rating
Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top