Uln2003a

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alanjackson13

Joined Jan 14, 2012
2
I'm driving a 5V 30KHZ square wave through a ULN2003A via a pic output.
The problem is the output of my ULN2003 switches from 5v down to 0.7v not 0V.
Can any one tell me how to get it down to 0v. I am using 10k pull up resistors on the output
 

#12

Joined Nov 30, 2010
18,224
It is inherent that a saturated bipolar transistor will still have a few tenths of a volt across it. The ULN2003 uses a saturated Darlington pair and that makes it worse. If you want to get closer to zero, you must change to a MOSFET output, and I don't know a part number for that right now.
 

#12

Joined Nov 30, 2010
18,224
That might work. Depends on the maximum current required. Half an amp with a 5 volt gate would make this one insufficient at 1.6 ohms D-S.
 

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