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UCC27210: UCC27210 Output Pulses are inconsistent

Part Number: UCC27210
Other Parts Discussed in Thread: LM5101

Hi Team, 

I am facing issue with UCC27210 driver output pulses. Below is the schematic.

Vbatt = 12Vdc typical 
Vgate = 10.5V dc

I tried by reducing the switching frequency till 50Hz. This behavior is consistent. If I replaced the driver with other sample then performance is different.

Also Increased the driver supply voltage till 15V & HI till 5.9V still no improvement in performance. 

Please check below waveform at 50Hz, where yellow signal is input & Blue is driver output. This is for low side FET.

Please, let me know if anything is missing in design. 


  • Boot strap capacitor value is 0.22uF. In bridge total 12 MOSFETs (3 In parallel). Remaining are optional. 

  • Hello Vaibhav,

    Just to confirm, you are seeing missing pulses on the low-side? Do you see issues on the high-side as well? I suspect that the missing pulses are a result of VDD dropping below the UVLO threshold. Can you capture the VDD line (Vgate) so we can see what is occurring there? I see you already tried increasing VDD to 15V, which should have helped if the UVLO is the issue, but let us check to be sure. 


    Alex Mazany

  • Yes, the missing pulses on the low side. In 50% driver samples, no low side pulses at all. Same behavior (missing pulses or no pulses) at high side also.

    No glitch or noise or voltage drop on VDD line. I will share the waveform soon. But I don't see any concern.  

    One more observation is that, this behavior is temperature dependent. If I increase the ambient temperature then frequency of missing pulse increases. I am trying to heat the driver using hot air gun. 

  • Hello Vaibhav,

    Please do share the waveforms. Could you also provide a zoomed-in capture of a normal and a missed pulse, including the VDD if possible? That should help us see what is going on better. In addition, have you seen this issue on multiple units? If so, we can likely rule out any device damage.


    Alex M.

  • This issue observed in all devices & all driver IC. Instead of spending time to resolve this issue, which looks like from driver batch. We used LM5101 driver & all devices working fine as expected. 
    We ordered 1000 samples of UCC27210, which is not useful for us anymore. 

  • Hello Vaibhav,

    I'm glad to hear that the LM5101 is working for you. If you decide to pursue the UCC27210 again, feel free to continue this thread.


    Alex M.