SN754410 destroyed?

Thread Starter

hcccs

Joined Nov 16, 2009
8
How easy is it to destroy a SN754410. I've connected one with 5V on pin 1 & 16, 12V on 8 and grounded pins 4, 5, 12 & 13. With this setup with no input on 2, 7, 10 & 15 there should be no output at all but I measure 11.8V on pins 3, 6, 11 & 14. That leads me to believe I've somehow destroyed the IC. I've tried with 2 other ICs and they react the same way. Have I overlooked something?
 

Thread Starter

hcccs

Joined Nov 16, 2009
8
AlbertHall,
When I connect 2 & 7 to ground the outputs 3 & 6 show 0.57V which seems OK. So, that was it?
 

Thread Starter

hcccs

Joined Nov 16, 2009
8
I think now I need a couple of pull-down resistors`on the input pins. Calculating from specs they should be around 50k. Does it sound right?
 

AlbertHall

Joined Jun 4, 2014
9,025
From the datasheet, the input voltage for logic '0' should be less than 0.8V and the input current is 10uA max so the pull down resistor should be less than 80k. I wouldn't go higher than half that and, for certainty, less than that, say 20k.
 
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