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DRV8703-Q1EVM: SO Output Pin Spike

ReedKacz
Expert 3657 points
Part Number: DRV8703-Q1EVM
Other Parts Discussed in Thread: DRV8703-Q1,

Hi Team,

As I was working with the DRV8703-Q1EVM, the sense amplifier output showed a large spike a few microseconds after the PWM goes high. I was able to remove this spike by disconnecting R37, which is the connection from the amplifier output on the DRV8703-Q1 to the MSP430.

Could you please explain why this spike exists and why it goes away with the removal of R37?

See below for an oscilloscope plot with R37 installed first:

(note the large spike does not line up with a current spike.)

See below for a correct plot once R37 was removed:

(note the spike here lines up with the current spike as expected)

Thanks!

Reed Kaczmarek

Analog Field Applications 

  • 0
    TI__Genius 14487 points

    Hi Reed,

    I tested our EVM on the bench and it appears to be related to the MSP430 rather than the DRV8703-Q1 device. When I reduce the VM supply on the EVM below the UVLO limit, the spike still exists, even though our UVLO protection completely disables the DRV8703-Q1.

    The scope shots below shows that the spike does not depend on duty cycle

    When I hold the MSP430 in reset using the button on the EVM and toggle the EN pin externally, the spike on SO does not occur.