CAB650M17HM3 Gate Resistance

pj8761

Hello,

Is the CAB650M17HM3 rated to be operated with zero external gate resistance (assuming SOA limits arent breached)?

I'm asking as the datasheet switching energy losses for the module are specified using an external on/off resistance of 1.5 Ohms, whereas for the CAS380M17HM3 the datasheet switching energies are given for 0 external gate resistance. Figures 15 and 16 in the CAB650M17HM3 datasheet show switching energy losses down the 0 external gate resistance so if it is rated to work down to this resistance why is 1.5 Ohms used for the headline switching energy loss values?

Thanks

AustinC

Hi pj8761,

Yes, the CAB650M17HM3 can be operated with 0 Ω external gate resistance. As you mentioned, it's necessary to ensure the module operates within its safe operating areas, so the RG must be tuned across all operating parameters (junction temperature range, peak current, bus voltage variation, etc.) to not exceed 1,700 V from drain-to-source. On our dynamic test characterization system, an external gate resistance of 1.5 Ω provided the most aggressive switching speed that we could tolerate with our system's parasitic inductance at these operating conditions: 1200 V bus, TVJ = 175°C, 1300 A. If your system has lower stray inductance or your operating parameters are lower, you will be able to decrease the external gate resistance, increase switching speeds, and lower switching losses.

Best Regards,

Austin

pj8761

Thanks for the quick reply, Austin - Clears things up for me nicely.