Gate driver datasheet mentions about VOLL and VOH with test conditions Iol=100mA


I am testing this using this setup by calculating value (ron of pmos is 7.05 ohms) of load to be placed, Is this the right test setup to check this parameter/ what is the functional meaning of this?

I am also testing peak pullup and pull down current which i got approximately proper result and mentioned in datasheet(dc and transient analysis) LM5102 figure 6.Test setup

Test setup waveforms

  • \$\begingroup\$ for excitement, insert 5 nanoHenry inductors GND and VDD pins of the gate driver. This begins to indicate the real-world behavior and waveforms. Also insert 10,000 picoFarad capacitor (the well-channel capacitance of the FETs) between GND and VDD. Enjoy the ringing. And reduce the pulsewidth to 100 nanosecond, with period of 200 nanosecond. \$\endgroup\$ – analogsystemsrf Aug 4 at 23:43

No, you should replace R1 with a constant current source of 100mA. If the direction of current is toward ground then use a value of 100mA for the \$V_{OH}\$ test and -100mA for the \$V_{OL}\$ test.

Your calculation of Ron from the datasheet parameters is not likely to be very close to the actual Rds in the simulation, and remember that this resistance is not a simple constant value.

The basic meaning of the \$V_{OL}\$ specification is: How low (in voltage) can the driver pull the output pin while sinking 100mA? The maximum value given is the worst-case, or highest possible voltage that can appear when the driver is trying to pull the output pin low. Likewise, the \$V_{OH}\$ specification tells you how high can the driver pull the output pin while sourcing 100mA. However, this datasheet doesn't specify the actual voltage for \$V_{OH}\$ but rather the difference between the actual output voltage and its ideal value (either \$V_{DD}\$ or \$V_{HB}\$).

  • \$\begingroup\$ Does Rd (0.8 ohm) dynamic resistance specify Ron of the PMOS / NMOS ? \$\endgroup\$ – Adithya Pai Aug 4 at 13:35
  • \$\begingroup\$ It's not clear from the small datasheet excerpt what the value of "Ron" means or exactly how it was measured. But you should notice that there is almost a 2:1 ratio from the typical value to the maximum value, which means there is probably a 3:1 or 4:1 ratio from the minimum to maximum possible values. If you want to test a given sample of the device you shouldn't expect anything except that Ron is less than 1.5 ohms. \$\endgroup\$ – Elliot Alderson Aug 4 at 15:24
  • \$\begingroup\$ Since I need source and sink current for which is 1.8A and 1.6A for which I have altered Kp value of PMOS and NMOS. What parameters does effect Voh and Vol \$\endgroup\$ – Adithya Pai Aug 5 at 16:40
  • \$\begingroup\$ That depends on what sort of simulation model you are using. There are several different models and each has its corresponding set of equations and model parameters. I don't understand the big picture here...I thought you were testing a commercial device. \$\endgroup\$ – Elliot Alderson Aug 5 at 17:27

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