MAS3:
Are those sidepods functional ?
Very unlikely.
If the body is metal, you can use that for heat dissipation.
But if you connect it directly, then you have GND on the body of your car and need to remind that.
actully the car is sort of plastic but the sidepods has a hole so i can make them functional which means, so they won't just be for the shape of the car but to give a bit of cooling for the IC
The sidepods only work if you are making some speed.
That will not be optimal so keep looking for a way to cool stuff.
Connect 4 pins to GND and make sure that you have an as large as possible surface around the pins.
That way that GND surface doubles as a radiator (sort of).
OP, I may have missed it, but I didn't see anyone asking you how much current your motors draw. ???
MAS3:
Do you read datasheets ?
...
Directly next to that on the left side, the datasheet tells you the device can handle 600 mA.
Earlier you were asking about H bridge drivers for over 1 A.
...
Not sure what the previous post is about, but it doesn't answer my question, and which should have been the VERY FIRST thing that OP found out about. You can't get anywheres if you don't know how much current the motors draw. 12V motors - could be 250 mA or 5A, etc.
Has anyone ever tried a heatsink on top of the IC, like this one ?
I would suspect it would have to be attached with heatsink glue. I have not tried it, but looks like it would be a lot of help if the IC is getting to hot.
Yeah, they sell several heatsinks for these sort of chips.
http://www.google.com/search?hl=en&site=imghp&tbm=isch&source=hp&biw=1028&bih=849&q=dip16+heatsink
They help somewhat, but you can't expect miracles with an L293D. Being a bipolar device, there is a typical 1V to 1.5V drop across the output transistors [see the datasheet], so "worst case" for 4 channels would be
Pd = 4 * (1V to 1.5V) * 0.6A = 2.4W to 3W,
and even with the better heatsink cited, the temperature rise would be on the order of
(2.4 to 3W ) * 46ºC/W = 110ºC to 138ºC. Pretty darn hot. Varies, of course, with fewer channels and less current.
@oric_dan:
OP has a lot of threads going on at the moment, and they all come to a certain point where he seems to just gather some stuff together and is trying to make it work without understanding a bit.
So he asks questions but always without enough information.
There is an other thread where he asked about controlling a > 1 A motor for his model car and the next day he started this thread.
He has told he does read datasheets but doesn't understand all of it.
I guess English isn't his first language too, complicating things.
But i've never seen him asking questions about things he doesn't understand in datasheets.
He does ask after buying parts, putting them together and gets stuck after that.
If it takes over 3 days to understand, he just gives up to start over with an other approach or part for the same project.
It is very hard to help OP because of all of this, and i really tried.
OK, to answer the original question "L293D overheated but not burned !! what's the solution "
Don't touch it if it is to hot !
It is very hard to help OP because of all of this, and i really tried.
Ok, I understand, hadn't seen the other threads. I just noted the most fundamental info was missing in "this" thread, :-(.
jackwp:
OK, to answer the original question "L293D overheated but not burned !! what's the solution "Don't touch it if it is to hot !
I've seen smoke come from a few chips, but only ever seen one chip actually "catch fire", and it was an L293D. The plastic end of the chip literally popped off, and flames literally erupted. It's still one of my favorite memories, ;-).
@oric,
I remember once about 40 years ago, using TTL , I wired something wrong, and as I leaned over to check the wiring, it EXPLODED, one piece of the IC shot by my head. I was thankful that it did not hit my eye. LOL
So - don't touch it, Don't even get close.
I see some people will pigiback these ICs for more current. I never tried it.
jackwp:
I see some people will pigiback these ICs for more current. I never tried it.
I always thought these guys were being a little bit silly,
oric,
Yea, what they say there is a bit unbelievable, I think stacking would not double the power ability, but maybe add around 40%.
Do you know of an ic that does not have such a heat problem (afordable) ?
MAS3:
@oric_dan:OP has a lot of threads going on at the moment, and they all come to a certain point where he seems to just gather some stuff together and is trying to make it work without understanding a bit.
So he asks questions but always without enough information.
There is an other thread where he asked about controlling a > 1 A motor for his model car and the next day he started this thread.He has told he does read datasheets but doesn't understand all of it.
I guess English isn't his first language too, complicating things.
But i've never seen him asking questions about things he doesn't understand in datasheets.
He does ask after buying parts, putting them together and gets stuck after that.
If it takes over 3 days to understand, he just gives up to start over with an other approach or part for the same project.It is very hard to help OP because of all of this, and i really tried.
actully starting from a higher level made me learn a lot 
and with ur help guys i am getting better everyday and understanding more about this world
jackwp:
oric,
Yea, what they say there is a bit unbelievable, I think stacking would not double the power ability, but maybe add around 40%.
Do you know of an ic that does not have such a heat problem (afordable) ?
There are a lot of MOSFET h-bridges that do a lot better, both integrated chips and descrete arrangements. Pololu has some pretty good boards.
firashelou:
actully starting from a higher level made me learn a lot
Do you know how much current your motors actually draw?
oric_dan:
firashelou:
actully starting from a higher level made me learn a lotDo you know how much current your motors actually draw?
not but i know the voltage 12V
it was an old RC car, the set of battery used in it is 700mA and 12V
but the circuit has 2 motors, first for traction and second for steering so ...
hey guys,
i am thinking about put a piece of metal like the one i have on the motor, for heat sink, wired to pins for heat sink and putting the chip in the sidepods so i can gain more cooling from the small air entering the sidepods when i am up with the speed
what do you think about this solution which you were talking about in a couple of posts ?
A real sidepod is made to direct an airflow.
Such airflow cannot exist if there is only an entry, there has to be some exit too.
Is this the case with your model car ?
The heat conduction doesn't have much up with wiring.
It needs a surface to be mechanical connected with, and the surface of the pins that touches the heat sink should be as large as possible.
So be sure those center pins of your l293d make a tight and as large as possible mechanical connection to your heat sinking material.