[Need suggestion for high output current DCDC] LTC3839

Question

To whom may it concern. 
 
 Hi i'm looking for the DCDC that meet these specification below. 
 Input voltage=12V, Output voltage=0.85V, Output current=33A, efficiency >0.9. 
 
 Q1-1. I found LTC3839 could be the option. I checked EVB - DC1632A but its output voltage is 1.5V. 
 Which part should i change the output voltage from 1.5V to 0.85V? 
 
 Q1-2. 
 What would be the efficiency if i change the output voltage of EVB - DC1632A from 1.5V to 0.85? 
 
 Q2. Is there better DCDC in efficiency wise under the condition i mentioned above?

Thank you!

MarkusHP · Answer

Hello, 
 answer for Q1-1 can be found in the datasheet resp. manual of the demoboard. If I answer your questions here you probably won't read it and this is something we both should avoid. Please come back with questions when you do not understand or found the answer in the datasheet. 
 Q2: As the LTC3839 asks for an experienced designer(controller with external FETs, many components to choose and layout carefully) I would recommend the LTM4650 to you, as this part is much easier to use and design time is much shorter. Efficiency might not be better, but there are other parameters in a DC/DC design which are key as well. And from your questions I think an integrated module is a better solution for you. 
 kind regards 
 Markus