Hello, we are using the UCC21710 (and UCC21737, but basically it should be the same for this question) with very small resistors for turning on and off - around 0.1 to 0.4 Ohm. As the internal turn on and turn off MOSFETs are given with a resistance within that range (off 0.3 and on 0.6), we would like to know if those resistances are quite similar from piece to piece of if they have a high variance - which we would have to consider then.
Thanks for your Support!
Hi Johannes,
Thank you for posting to E2E.
The variance of internal resistances of the gate driver are provided in the datasheet electrical characteristics specifications. This variance considers both temperature and part to part variation. ROUTH is the impedance of the pull up PMOS FET and ROUTL is the impedance of the pull down NMOS. The output structure of the UCC217xx family has a hybrid structure for the internal pull up which is made up of the PMOS fet spec'd for ROUTH and also has a the NMOS spec'd for ROUTL in parallel. More details on the hybrid structure can be found in section 8.3.2 Driver Stage (page 24) in the uCC21710 datasheet.
For an idea on the temperature dependencies you can take a look at figures 6-4 and 6-5 in the UCC21710 datasheet (page 12) which is the output source and sink current of one typical device across temperature which current output is dependent on the internal resistance.
Best regards,
Andy Robles
