Electronic – Level shifting: from 0-3.5V range to -2/1.5 range

level-shifting

I have a signal (digital) which has output levels of 0V (logic 0) and 3.5V (logic 1).

I would like to know if it is possible to shift it between -2V (logic 0) and 1.5V (logic 1).

I found here on stackexchange and on google various example, but they all assume positive levels (0-5 or 0-3.3) and I don't really understand how to make them work in my case.

Thanks for all the help

EDIT after a couple of questions:

  • I have available easily on board: -2V, 0V, 1.5V, 5V
  • I am sending the signal to a CMOS logic gate

EDIT 2:
Just to add a bit more to my question:

if you look at this thread
Level shifting a +/- 2.5V signal to 0 – 5V

the first answer provides a very nice circuit to do level shifting.

My problem is that I do not understand how to modify the circuit to fit my needs (see above).

In particular, I am quite puzzled by the supply value of the OpAmp. It looks to me I should use +1.5 and -2, but then I get lost in understanding what is going on.

Best Answer

schematic

simulate this circuit – Schematic created using CircuitLab

The LM358, being a single supply op amp, saturates in the negative direction within a few mVs of the negative supply rail.