DRV10983: SPEED PIN Abnormal Voltage when Floating

Alvin Zheng

Part Number: DRV10983

Hi, Team

One customer reported an issue on DRV10983Z version.

When leave the SPEED PIN floating (disconnected every thing from the PIN), as spec shows, there should be a 55Kohm pull down to pull SPEED low and the motor should be stopped. But in real, there is a >1V measured on SPEED PIN and motor keeps rotating. Settings are properly loaded and SPEED is set as PWM mode.

Could you please check the SPEED PIN structure and offer an explain?
Thank you.

over 6 years ago

0 Brian Schmidt over 6 years ago

TI__Intellectual 2600 points

Alvin,

The spec is intended to make sure that a large enough pull up is used to come out of sleep mode. This is not a pull down that is normally there. The requirement for this pull down to be active is that the SPEED pin has to be 0V (therefore the customer must drive the pin to 0 before the pull down is active).

Let me know if that explains it.

Thanks,
Brian

0 Alvin Zheng over 6 years ago in reply to Brian Schmidt

TI__Intellectual 900 points

Thank you, Brian.
I will suggest customer to add pull down resistor and see if the issue is fixed.

0 Alvin Zheng over 6 years ago in reply to Brian Schmidt

TI__Intellectual 900 points

Hi, Brian

Customer added 1Kohm pull down but there was still voltage presenting on SPEED pin. It looks like there is current come out of SPEED pin. What is the structure of this pin?

0 Brian Schmidt over 6 years ago in reply to Alvin Zheng

TI__Intellectual 2600 points

Alvin,

Here is the structure of the SPEED pin. I'm not sure what would be pulling the pin up.

Thanks,

Brian

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DRV10983: SPEED PIN Abnormal Voltage when Floating