I intend on driving 24VDC relays with darlington arrays of the ULN200X series. Since the darlingtons will be driven by a 3.3VDC outputs I am hesitating on whether I should choose ULN2003 or ULN2001.
As mentioned in the datasheet ULN2001 works with: general purpose, DTL, TTL, PMOS, CMOS. However it does not mention the voltage levels. On the other hand ULN2003 works with 5V TTL, CMOS. The only difference between the two would be a series resistor:
Since the resistor is not existent in the ULN2001, would this mean that driving it with 3.3VDC would be much easier than in the ULN2003 case?
Each relay draws ~20mA. According to the electrical characteristics, "VI(ON)" of max 2.4V is sufficient for 200mA loads, in the case of ULN2003. I guess this means that ULN2003 should be ok with 3.3VDC but I still wanna make the better choice between the two.
The MCU I use is stm32 with general purpose I/Os which are TTL and CMOS compliant according to the datasheet.
Advise on alternative components regarding this application is most welcome.