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DRV8718-Q1: Whether DRV87180-Q1 current amplifier has S&H function

Hale Tan
Expert 3770 points
Part Number: DRV8718-Q1

Hi team,

Does DRV87180-Q1 current amplifier has S&H function as below? The block diagram has S&H function but I didn't see any description about it.

And I see that DRV8705 has this function. Could you help explain this function application? Why do we need this function? Thanks in advance.

  • 0
    TI__Mastermind 19060 points

    Hi Hale,

    The Blank S&H block is further described in the datasheet as the "Output Blanking Switch" and is only available on the SPI variants. This switch can be used to reduce the noise by disconnecting the amplifier output during PWM switching. 

    More information on how to configure the Output Blanking Switch can be found pages 48-49 and the control register maps of the datasheet. 

    Best,

    David

  • 0 in reply to David Medis
    TI__Expert 3770 points

    David,

    The function block you mentioned is a switch which can use to disconnect the amplifier output. But I asked whether DRV8718-Q1 has sample and hold function. If have, how to configure? And what is the application of sample and hold function?

    Thanks.

  • 0 in reply to Hale Tan
    TI__Mastermind 19060 points

    Hi Hale,

    An output hold up capacitor is recommended at the output of the SOx pin to "hold" the voltage during PWM switching. A resistor can be connected in series in RC configuration to reduce the capacitance seen at the SOx pin. 

    The Amplifier Blanking Example in Figure 8-21 shows an example of the Vso output voltage being "held" during the blanking time. 

    Best,

    David