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Major Mistake in my design

Question asked by cavanagh.brian.001 on Mar 29, 2016
Hi, I attached my schematic to help in my discussion.  I made a huge mistake by selecting a Linear Regulator U200: (12Vin - 5Vout).  Roughly I'm drawing about 1.5Amps, therefore my power dissipated across the IC is (12 - 5)(1.5) = 10Watts.  Yes, it overheats and always trips.

The main input voltage to J200 is 5 - 42.  It connects to an LM25118 12Volt output regulator.  I made the decision to use the 12V design because I do need a 12 volt output on my board.  I'm using this same 12V output to feed U200 and U203.  

I would like to replace U200 with perhaps a switching regulator to help with the power dissipation.  

Other ideas are certainly welcome.  Designing to allow for unforeseen current draw is ok. I'm at the second spin on this board and clearly my customer is not happy.