hi,
i want to control movement of my robot through motor driver ic. when i am using l293dne(texas instruments) its not working at all but when i am using l293d(st) its perfectly working. can you tell me why this problem is arising.

 

Welcome to AAC!
The most likely answer is that the TI chip is dead. Are you sure it isn't a fake?

 

but i tested with two chips.how can both r dead.those are new one.

 

What clues can you find in the datasheet about the differences?
As near as I can tell the DNE suffix just tells you it is the higher current model in the PDIP package and is ROHS compliant.
Who did you buy the parts from? Unscrupulous vendors sell plastic packages with empty leadframes to unsuspecting hobbyists all the time.

 

L293DNE datasheet i didn't get. all i get L293D datasheet.but for testing when i used to rotate 5v motor,those are rotating but 12 v is not rotating.i got these ics from local eletronics shop

 

TI datasheet is here:

http://www.mouser.com/ds/2/405/l293d-441879.pdf

As you can see the DNE suffix is just about packaging.

 

i saw it already.if both st and ti datasheet are same.then why its not able to rotate.what problem it has..

 

I don't know. Unless you can provide pictures of the packages or convince us you bought them from a reliable supplier my assumption is you have counterfeit parts or parts with an empty leadframe and no silicon inside.

 

Sometimes the "D" at the end of the part number means there are back-EMF diodes on the driver outputs.

 

Sometimes the "D" at the end of the part number means there are back-EMF diodes on the driver outputs.

Not in this case. The D in the suffix is a higher current part, IIRC 600 mA.
In any case he is asking about the difference between STMicro L293D, and TI L293DNE. The additional NE just specifies the PDIP package that is Lead Freee and ROHS 2006 compliant. It doesn't explain why the ST parts work and the TI parts don't.

 

Not in this case. The D in the suffix is a higher current part, IIRC 600 mA.

A look at the data sheet for the STMicro L293D shows prtotection diodes in the output. The data sheet for the TI L293DNE says:
"Output diodes are internal in L293D."

So... both parts seem to have the output protection diodes. So much for my theory for what the difference might be.