Are ATMEGA32L and ULN2003A Logic Levels Compatible?

[j777]

I'm working on a project that uses an ATMEGA32L uC (3.3V supply) and requires a couple high current outputs. To accommodate the requirement of the outputs I'd like to use a ULN2003A darlington transistor array but my concern is that the logic levels of the ATMEGA32L and ULN2003A aren't completely compatible (VOH in particular). Since I'm just a beginner, would somebody mind commenting on the compatibility between the outputs of the ATMEGA32L (3.3V supply) and the inputs of the ULN2003A?


Datasheets:
http://www.atmel.com/dyn/resources/prod_documents/doc2503.pdf"
http://www-s.ti.com/sc/ds/uln2003a.pdf"


Thanks

 

[Averagesupernova]

The 2003 I believe has a 2.2K series resistor on each input. I didn't look at the data sheet, I'm going off of memory. It is most certainly made to work off of 0 or 5 volt logic levels. However, depending on what you have hanging on the output of the 2003, the 3.3 volt input may work just fine. The thing that could be a problem is the output transistor may not be turned on all the way and dissipate more power than it normally would due to the voltage drop across it. It really depends on your specific application.

 

[ravenprp]

for reaching out for help with your project! The compatibility between the ATMEGA32L and the ULN2003A depends on the specific voltage levels and thresholds of each component. In general, it is important to ensure that the input voltage levels of the ULN2003A are within the allowable range for the output voltage levels of the ATMEGA32L. Looking at the datasheets for both components, it appears that the ATMEGA32L has a minimum output voltage of 2.4V and a maximum output voltage of 2.9V when operating at a 3.3V supply. The ULN2003A has a minimum input voltage of 3V and a maximum input voltage of 5.5V. This means that the output voltage levels of the ATMEGA32L may not meet the minimum input voltage requirement of the ULN2003A.

However, there are a few options for addressing this issue. One option is to use a level shifter to convert the output voltage levels of the ATMEGA32L to meet the input voltage requirements of the ULN2003A. Another option is to use a different transistor array with compatible voltage levels. It is also possible to adjust the output voltage levels of the ATMEGA32L using a voltage regulator or resistor network. Ultimately, it will depend on the specific requirements and limitations of your project. I would recommend consulting with a more experienced individual or doing some additional research to determine the best solution for your particular situation. Good luck with your project!