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DRV5013-Q1: What is the maximum capacitance that can be attached between OUT pin and GND?

Part Number: DRV5013-Q1

Hello guys,

One of my customers is considering using DRV5013-Q1 for their next products.

They have the following question about the device at the moment.

Could you give me your reply?

Q. We want to attach a capacitor between OUT pin and GND like C2 of the block diagram in section 7.2 on page 10 of DRV5013-Q1 datasheet ( Ver SLIS162H).

    Could you please tell me what the maximum capacitance is that can be attached between OUT pin and GND?

Your reply would be much appreciated.

Best regards,

Kazuya.

  • Kazuya-san

    Thank you for your question.  The output capacitance may be limited in a few ways.  Firstly, this capacitor limits the effective sampling bandwidth of the sensor.  The output will slew more slowly with larger capacitors and can limit the ability to detect fast changing signals in a timely fashion

    The other factor is the output current limit.  The device has over current protection with a minimum possible value of 15 mA. 

    The current into a capacitor is I = C × (dV/dt).  If too large a value of C is used, then the device will potentially engage the OCP.

    Thanks,

    Scott

  • Hello Scott、

    Thank you for your reply.

    Could I ask you the following additional questions?

    If OUT Fsw is less than 1Hz (almost DC level) and long magnetic detection delay is allowed, is C2 value no limit?  

    Is it OK to attach 10uF or 100uF capacitor?

    Is there any concern for device damage when such big capacitor is used for C2?

    (I think it is no concern because OCP is implemented to OUT terminal)

    Thank yo again and best regards,

    Kazuya.

  • Kazuya-san,

    With a 100 uF capacitor, a dV/dt of 150 V/s would result in a current into the capacitor of 15 mA.  Since the device is set to use the OCP to clamp the current to protect the device, the result would be that the output slew rate would be limited to approximately this speed.  Depending on the supply voltage, this will impact the total time required for a transition change.  

    Between this response and the RC rise time, there will be delays between the change of magnetic input and the valid output signal.  If this delay is acceptable, then I would expect these capacitances might be used.

    Thanks,

    Scott