L298/L297 Circuit

Thread Starter


Joined Sep 25, 2007
I just finished making the L298/L297 Circuit for a Bipolar 2-Phase stepper motor... But before hooking it up with my microcontroller circuit i want to check n make sure the circuit is working fine... How do i check it and what should be the voltages on the output of the L298 and what should be the voltages on the Clock,Enable,CW/CCW and Reset pins of the L297...

I connected the chips to 5V and the Vdd of L298 to 30V and I am getting around 6V on the above mentioned pins of the L297 (It would be safe to connect it to a uC?) and on two outputs of L298 I am getting 0V and 17V on the other two...
Why 17V? Should it be this way...?
Secondly i wanted to know which wires of the stepper motor would go into the four outputs? Does the order matter... as when i change the configuration the voltages on the output change....



Joined Jul 17, 2007
Well, if you don't have a load hooked up to the L298, you're going to see some pretty high voltages. The L298 wants to see a voltage across the sense resistors. You put those in, right?

Did you download the datasheets for those IC's? If not, STMicroelectronics has them on their site:

Most of your questions will be answered by reading the datasheets carefully. You'll need to do that anyway.

Check the datasheet for your stepper motor(s) - they're not hard to find - unless they're real oddballs.

Reading the documentation beats the heck out of letting the smoke out of your omponents ;)


Joined Jul 17, 2007
Here's the circuit.. Is something wrong or missing?
What should be the output on the four outputs of the L298?
Follow my instructions above.

Look at page 8 in the L298 datasheet.

Most of the battle is just knowing where to look for the documentation.

Work on that aspect - it'll help you a lot.