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L293D Motor driver

Vendor's Description: 

This chip enables you to take 4 outputs and turn them into 2 that can be reversed.

Note that the chip can get quite warm, but it is designed for that. 



You can control 2 motors in both directions instead of 4 in only one direction. 



There is a 1.5V voltage drop within the L293D driver chip.

If you run both motors and servos on the same circuit, your servos will allways get 1.5V more than the motors - and typically you would want it the other way around! 

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Everyone's got a favorite chip, but have a look at the SN754410. http://focus.ti.com/docs/prod/folders/print/sn754410.html.

The L293 has 1A drive, but no clamping diodes while the L293D has 600mA drive with clamping diodes. The SN gets you both 1A and diodes, and they're a tad cheaper at Digikey or Mouser (in the US at least). And they're otherwise pin-compatible, so you don't even have to change your designs.



I think the manual indicates that diodes inside the SN754410 are for ESD protection not for kickback protection by the motor's inductance. Use it for kickback protection is not gauranteed.




You are right. We had a discussion about this in another thread recently.

"And they're otherwise pin-compatible, so you don't even have to change your designs."

Wow, thanks, Elliot, that is very, very interesting for us who tend to use standard boards. Thank you very much! 

/ Frits 


I'm going to wire up my motor driver (on a breadboard of course I want to learn which pins do what) and I have a couple questions. According to the datasheet (http://www.rev-ed.co.uk/docs/L293D.pdf) it looks like I know the following pins:

  • Pin 8 supplies volatage to the chip (I'm using 5volts)
  • Pin 2 connects the picaxe pin to motor 1
  • Pin 3 and 4 connect to motor 1

Is the above true? If so what is Pin 1 (Enable 1) and Pin 16 (VSS Logic Supply Voltage)

I know it would be easier to use the project board, but I'm an overachiever ;) I want to understand things more than I need to. Once I figure it out I'll document it so I won't have to ask again.

As usual I figured it out after I posted. I looked at the datasheet for the 28x project board and it had specs for the motor driver. http://www.rev-ed.co.uk/docs/AXE020.pdf

Bottom of page 4 shows the pins for the motor driver.

Is this only for picaxe or can it be used with other applications? 


Of course it can be used with anything, it is just a motor driver, has nothing to do with Picaxe!