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LM193 Low Level Output Current (Iol)

Other Parts Discussed in Thread: LM193

The LM193 electrical characteristic sheet on page 5 has a specification of 6mA for the Iol.  It has the test conditions of Vol=1.5v and Vid=-1V for 25C.

In the Vol specification right above it there is a 0.15 to 0.4V for the Vol for Iol of 4mA, Vid=-1 and 25C.  Looking at the typical curves on page 8 figure 3 it shows under typically the Vol vs Iol for 125C, 25C, and -55C.

My question is what does the min 6mA Iol mean in the electrical characteristics sheet?  I guess it could mean it's possible to 1.5V Vol for as little as 6mA, but non of the other figures or spec's support that (that I can tell).

Thanks,

John

  • John,

    The 4mA VOL will always be in the saturated (resistive) region of the curve.

    The vertical section where the output NPN is a current source will happen at 6mA or higher. 

    In the data sheet curve this happen at 20mA (which is higher than the 6mA minimum)

  • Ron,

    Thanks for the response.  Let me make sure I understand for my application.  I have an application that will require 8-9 mA sink current.  Based on my understanding of your answer, the LM193 might go into current source mode at 6mA and my output voltage would go to the voltage that is dependent on 6mA and my output load.

    Is my understanding correct?

    Thank you!

    -John

  • John,

    Yes, you are correct.

    Most devices will support your 8-9mA need. However there may be a batch of parts that don't have enough current sink.

    To be safe you could parallel outputs or add a transistor at the output to boost the current drive.