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Bad Overheating problems with L6474 , Help!

Question asked by kenny.larry on Sep 5, 2014
Latest reply on Oct 15, 2014 by Enrico Poli
I'm finding that the L6474 runs terribly hot even at 1.4 amps . Its on a decent PCB with 20 plates thru tholes a small heatsink (1" x 1") on the back and it will rise to 110 C in less than 2 minutes . It is the power36 package too.  My PS voltage is 42 volts.

 My charge pump voltage is about 8 volts. And it doesn't matter much whether i power the logic externally with a 3.3 volt regulator or not.

 I've put a lot of effort into designing this small controller , but at this rate i may have to move to a better chip.
 I've used the L6207 in the past and it ran very cool at 2amps/phase and 45 volts.  It was the larger 24 powerDip

 Why would ST make this chip so small and have mosfets with a high on resistance ?  A larger chip would have been alot better. I can't even imagine using the L6474H with the tiny TSSOP package.  
 If ST made this chip in a much larger package with wider pin spacing , i'm sure customers. would be happier. The motor a chip rated at 3 amps and 45 volts is quite big. Why does the chip have to be microscopic ?


 
 

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