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DRV8847: replace DRV8833

Howard Zou
Genius 12365 points
Part Number: DRV8847
Other Parts Discussed in Thread: DRV8833, , DRV8837

Hi,

my customer is testing DRV8847 to replace DRV8833.

In DRV8833PWP, pin11 is connected to pin12 through a cap, pin14 is connected to GND through a cap.

In DRV8847PWP, pin11 is TRQ, does this pin has internal pull down resistor? What's the state of this pin if left floating?

pin 14 is MODE, we should pull this pin to GND through 0ohm resistor to make the bridge mode the same with DRV8833? So we should replace the cap with 0ohm resistor when replacing DRV8833 with DRV8847?

  • 0
    TI__Genius 12365 points
    My customer is using DRV8833 in many of their product. So we can't replace it with DRV8847 if we can't keep the PCB unchanged.
  • 0 in reply to Howard Zou
    TI__Guru** 114905 points
    Hi Howard,

    Connecting MODE to ground, and floating pin 11 will make the DRV8847 operate like the DRV8833. There are few difference and items to double check.

    1) The current sense resistor should be adjusted. The DRV8847 Rsensexx resistors should be ~75% of the DRV8837 Risense resistor.

    2) The decay modes are different between the DRV8833 (slow) and DRV8847 (mixed). If this is acceptable, there should be no issue here.

    3) Floating Pin 11 of the DRV8847 may allow noise to affect the TRQ operation. We will have to research this and reply early next week.
  • 0 in reply to Rick Duncan
    TI__Guru** 114905 points
    Hi Howard,

    We are still investigating if floating pin 11 could cause any problems.

    If the customer is considering modifying the PCB, please request that a resistor footprint to ground is added on pin 11. This would allow the customer to populate the board for either device and not worry about any possible noise issues.

    We hope to have a further update by the end of the week.
  • 0 in reply to Rick Duncan
    TI__Guru** 114905 points
    Hi Howard,

    We have run experiments with pin 11 floating, and no problems have been identified.

    As previously mentioned, if the customer is considering modifying the PCB please request that a resistor footprint to ground is added on pin 11. This would allow the customer to populate the board for either device and not worry about any possible noise issues.