Piggybacking SN754410's

Adafruit Ethernet, Motor, Proto, Wave, Datalogger, GPS Shields - etc!

Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.
Locked
motorman12
 
Posts: 18
Joined: Mon Oct 31, 2011 4:03 pm

Piggybacking SN754410's

Post by motorman12 »

Hello everybody,

In a sense this thread is a continuation of this: http://forums.adafruit.com/viewtopic.php?f=31&t=23830

Anyways after that whole project it turns out the piggybacked L293D's I used were unable to reliably handle the current of the motors I chose. They could hold the load of the motors for a little while, but after a few minutes they would nearly burn to the touch. I would like to be able to hold the load for at least 15 minutes, and thus was wondering about Piggybacking SN754410's. Is there any reason not to do this? Sorry I am still a novice with all this electronics business.

I had to rush the project before to make some presentation deadlines, but it is a lot more laid back now so I can take my time and get everything right.

From this thread: http://forums.adafruit.com/viewtopic.ph ... 5&p=111117 I can see that the support guys are familiar with heatsinking the chips as well.

If piggybacking the SN754410's is okay, it would also be extremely helpful if you could provide me a decent heat dissipation solution as well :D

User avatar
adafruit_support_bill
 
Posts: 88087
Joined: Sat Feb 07, 2009 10:11 am

Re: Piggybacking SN754410's

Post by adafruit_support_bill »

You can piggyback the SN754410's just like the L293D's. If you are pushing them hard, a heatsink is a good idea too.

Aavid makes a clip-on heatsink for DIP packages. When piggybacked, you can only attach the heatsink to the top chip (and you need to attach it prior to soldering the chips together). But the way it is designed, part of the clip will be between the top & bottom chip so it will help dissipate heat from the bottom chip too. Also add some thermal paste to all mating surfaces for best performance.

motorman12
 
Posts: 18
Joined: Mon Oct 31, 2011 4:03 pm

Re: Piggybacking SN754410's

Post by motorman12 »

So something like this:

http://parts.digikey.com/1/parts/988336 ... 0000g.html

Also (this is a stupid question), when you say apply thermal paste to all mating surfaces, do you mean anywhere the clip-on sink comes in contact with the SN754410? I was thinking I'd use this stuff: http://search.digikey.com/us/en/product ... ND/2268500

User avatar
adafruit_support_bill
 
Posts: 88087
Joined: Sat Feb 07, 2009 10:11 am

Re: Piggybacking SN754410's

Post by adafruit_support_bill »

Yes on all counts. :D
A little of that grease goes a long way. If you use too much it will make a mess when you squeeze it all together.

Some small spring-clamps or alligator clips are handy to hold everything together while you solder.

Locked
Please be positive and constructive with your questions and comments.

Return to “Arduino Shields from Adafruit”