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DRV8306EVM: Enable Pin Locking Problem

Part Number: DRV8306EVM
Other Parts Discussed in Thread: DRV8306

I have Been trying to use the DRV8306 Evaluation module, Initially the development board which was ordered worked very good. I was able to run a BLDC motor with Hall sensor Both Single Ended and Differential upto RPM of about 90,000. All the Features were correctly. The Problem which i encountered was with the enable pin of the DRV8306 IC. According the Datasheet of DRV8306 and Start Guide of DRV8306EVM.It is Clearly mentioned that for the driver IC to be Enabled the enable Pin must be left Either Floating or Should be Pulled up using a suitable Pullup resistor. Now The Problem is that the 3 Evaluation module which i had ordered have a dedicated switch for enabling or Disabling a the IC. For Disabling the IC it is Connected directly to ground, But for enabling the schematic and PCB file shows a 10K pullup resistor but this resistor is not populated on all the 3 modules. Now to find out why this was done i Soldered a 10K pullup Resistor and tried to test it again. The Problem is that the DVDD supply LED which was glowing directly earlier is not glowing. When i switch the toggle switch back and forth the dvdd supply LED glow. If was trying to figure out that the dvdd supply which is generated by the internal buck converter in the IC is not able to enable the IC. I request to please mention this thing in datasheet as I desgined my own board for prototyping and i had pulled up the enable pin using the dvdd generated by IC and Since i pulled up the Enable pin Usign the resistor the Board was not working because the IC was Disabled. After Desoldering the pullup resitsor in my board everything worked fine.

  • Hello Nikhil,

    Yes, you're exactly right. If the part is disabled then DVDD goes down so any circuit relying on that source will not  function. This is shown in the datasheet snippet below.

    As such, we'll be changing the text in the user guide because it does not accurately cover the problem situation where R1 is populated. Thanks for pointing this out to us.

    Best,

    -Cole