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THS3491: PD internal pull up

Hirokazu Takahashi
Expert 8420 points
Part Number: THS3491

Hello Support team,

According to datasheet of THS3491, the default of PD pin is high, amplifier enable.

Does it mean PD has the internal pull up resistance?

If we want make THS3491 always active, is there any concern for making PD in the opened state?

Best Regards,

Hirokazu Takahashi

  • 0
    TI__Mastermind 22350 points

    Hello Takahashi-san,

       You are correct, you may leave the PD pin floating, which defaults to 2V below the positive supply voltage via connections to power supply/ground reference internal to the amplifier. Therefore, leaving the pin floating enables the device. Although the PD pin can be floated, we do still recommend terminating/driving the PD pin in case stray signals couple into the pin and cause unintended turnon or turnoff device behavior. 

       Quick note on if the customer is using the THS3491IDDA. The DDA package of the THS3491 has a reference pin (REF) that sets the enable/disable threshold levels of the device. The REF pin must be set to a voltage, typically to ground. 

    Thank you,

    Sima