Modification Instruction R-Ref01-HB

Infineon has recently released the new M1H series of SiC Mosfets. With this generation, Infineon recommends a different gate-source drive voltage than that used with their other series or those used by other manufacturers. The recommended turn-off voltage is zero volts, and the turn-on voltage is close to +18V.

The absolute maximum gate drive voltage limits are -7/+23V.

The standard R-REF01-HB design could be used to evaluate these transistors using the included +15/-3V DC/DC converter (R12P21503D). However, the M1H transistors would not operate when fully enhanced. So, although the existing layout would work, compared to the recommended +18V gate-source voltage, there would be significantly more conduction losses.

RECOM’s DC/DC power supplies are very flexible. Instead of using the +15 /-3V asymmetric outputs, you can use the same DC/DC converter to generate a single-ended 18V supply. However, as the R-Ref01-HB was designed to work with a dual supply, you would need to make some minor modifications to the board.

1. Open the box with the R-Ref01-HB and take out two of the R12P21503D DC/DC converters from the DC/DC converters included in the kit.
   (Alternately, you can also use two R12P209D instead that are not included in R-Ref01-HB kit)
   
   
   
   Fig. 1: Select the right converters



2. Snip off the Gnd pin on the +15V/-3V side of the converters.
   Make sure that the pin is cut as short as possible. The pin should not make contact with the uppermost PCB pad of the R-Ref01-HB.
   (Note: If you make your own PCB layout using these converters, it is not compulsory to remove this pin - just leave it disconnected (NC) in the layout)



Fig. 2: Remove GND pins



3. Insert the converters into the R-Ref01-HB PCB.
   
   
   
   Fig. 3: Mount the converters



4. Solder the pads on the bottom side of the PCB, leaving the middle GND pad unsoldered for now.
   
   
   
   Fig. 4: Solder converters



5. The next stage is to make a ...