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BOOSTXL-DRV8320H: Pull up resistances for hall sensor inputs.

Part Number: BOOSTXL-DRV8320H
Other Parts Discussed in Thread: DRV5021

Hi all

Would you mind if we ask BOOSTXL-DRV8320H(EVM)?

On the circuit, there are pull up resistances(R28~R30) for hall sensor inputs. 

What are these used for?Are these for the polarity of hall sensor inputs?(High active or low active)
Or, for Align operation??

Kind regards,

Hirotaka Matsumoto

  • Hello Matsumoto-san,

    Most single ended hall ICs, as opposed to differential output hall elements, have open drain outputs. Check out the DRV5021 for example and look at the block diagram in the datasheet: 

    As such, the open drain output needs a pull up resistor. Some hall sensors have a pull up integrated so the resistors are not needed and can be depopulated.

    So to be more general, the pull up resistors are needed for the hall IC sensor to toggle and function on a basic level as there will be no position feedback if the hall sensors cannot toggle.