photocoupler base pin

[snaoz]

HI

going trough this photocoupler data sheet LTV-4N35, i can't find any information about Pin-6, the output transistor base pin. why is information like the BETA not mentioned if they have provided a pin for the base ?

**broken link removed**

 

[Audioguru]

The datasheet shows a graph that shows a reduction in sensitivity when a base-emitter resistor is added.
But there is a mistake because TWO lines are marked 100k. So one line is probably 10k or the other line is 1M.

 

[snaoz]

The datasheet shows a graph that shows a reduction in sensitivity when a base-emitter resistor is added.
But there is a mistake because TWO lines are marked 100k. So one line is probably 10k or the other line is 1M.

I dont get it, why is there a base pin in the first place ?

 

[D.A.(Tony)Stewart]

I dont get it, why is there a base pin in the first place ?

You don't need nor should use the base, but it is there for testability and for those who know how to use it for an attenuator input control in isolated regulators.

The CTR is the product of hFE, PD sensitivity [mA/mW], IR LED efficacy mW/mA, which is guaranteed to be unity gain at room temp, new, but will reduce with aging from IR lumen maintenance (but not spec'd) and reduce with higher temp (is spec'd)

 

[snaoz]

attenuator... does it mean that pin 6 like audiguru mentioned is to make the phototranaistor less sensitive to the light signal it gets from the LED ????