LTC3728's Parallel Operation

Question

Hello, I am considering the LTC3728. Is it possible to configure a parallel output using the LTC3728? I would like to use it in the configuration shown below. 5V&rArr;1.8V/20A Best Regards,

mike.shriver · Accepted Answer

Hello, 
 Yes, the LTC3728 can be configured for a single output, dual phase converter. The data sheet does not show examples, but this has been done before. When paralleling phases, make these connections: 
 
 Tie VOUT1 to VOUT2 
 Tie the VOSENSE1 pin to the VOSENSE2 pin 
 Tie the ITH1 pin to the ITH2 pin 
 Tie the RUN/SS1 pin to the RUN/SS2 pin 
 
 An example is shown below:

If the 5V input will drop below ~4.7V during normal operation then tie the VIN and INTVCC pins together and tie the combined pins to the 5V input with a 1Ω or 2.2Ω resistor. Since INTVCC supplies the gate drive voltage for the top and bottom MOSFETs, this will ensure the MOSFETs have a sufficient gate drive voltage. 
 More recent dual phase / dual outputs parts to consider are the LTC3850, LTC3855, LTC3869, LTC3875, LTC3838/-1/-2 and others. Single output dual phase controllers to consider are the LTC3856 and LTC3839. 
 Best regards, 
 Mike

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LTC3728's Parallel Operation

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