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Temperature of MIC29300 is very high.

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diepvu1805

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Hi all,
I am using MIC29300-5.0BU in my design. But I have a issue with temperature of MIC29300.
When I supply 12VDC to Vin and the load is very low (100mA). MIC29300 is very hot although I used PCB heat sink for TAB (package TO263) with size: 12x12mm.
But when I used Vin 6VDC. I haven't meet that. Temperature of MIC29300 is low.
In the my other board, I use MIC29302BU and Vin 12VDC but temperature is low.
I don't explain that.
Could you help me, please?
Thank,
 

dick_freebird

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Pdiss=(VIN-VOUT)*IIN so you have roughly 7X the power
dissipation in the 12V case. So expect 7X the temp rise.

Board as heat sink is only as good as your airflow.
 

mtwieg

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That's just how linear regulators are. The formula dick posted is correct. Another way to look at it is in terms of efficiency. With linear regulators, efficiency=Vout/Vin. If you're stuck with a given Vin and Vout, and you want higher efficiency than that, then you need a switching supply.
 

raylay

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That's just how linear regulators are. The formula dick posted is correct. Another way to look at it is in terms of efficiency. With linear regulators, efficiency=Vout/Vin. If you're stuck with a given Vin and Vout, and you want higher efficiency than that, then you need a switching supply.
The LDO low efficent,let more power convert to heat. if you let 12V to 5V, better use DCDC.
 

diepvu1805

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Thank you for helping me. I thinhk, I should use the switching solution.
 

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