What is the required input voltage (V_I(ON)) for ULN2001A?

[kevindarmstadt]

For the ULN2002, ULN2003, and ULN2004 the datasheet gives detailed information depending on the continuous collector current, but no such info is given for the ULN2001.

[Peter BENSCH]

Welcome, @kevindarmstadt​, to the community!

There is a simple reason for this: the ULN2001 is a simple multichannel bipolar Darlington transistor, whereas ULN2002...2004 each have a series resistor at the base.

The ULN2001 is therefore driven like an npn transistor, except that it has two base-emitter junctions in series, as is usual with Darlington.

You will find the differences in fig 1 on page 3 of the data sheet.

Does it answer your question?

Regards

/Peter