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TCA9517: VOL under 0.4V but P2P TCA9517

Bonnie Chen
Intellectual 1150 points
Part Number: TCA9517
Other Parts Discussed in Thread: TCA9802, PCA9306

 Hi Team,

can you recommend solution that VOL under 0.4V but P2P TCA9517?

  • 0
    TI__Guru 73181 points
    Hey Bonnie,

    We do have a solution for this, that would be the TCA980x family. B side of the device does not (will not) work in a pull up resistor so you will need to remove that.

    Thanks,
    -Bobby
  • 0
    TI__Guru 62920 points
    Hi Bonnie,

    Do you mean on the "B" side? This device intentionally introduces a ~500-mV offset on this output as a way of distinguishing between when a device on the "B" side is pulling low (and so the level is close to 0 V) and when a device on the "A" side is pulling low (in which case the "low" level is being propagated through the buffer circuit). Many other buffers will operate the same way - it is generally referred to as a "static voltage offset."

    One alternative part you may want to look into, though, is the TCA9802. It uses a different mechanism to control the direction of data flow (based on current detection rather than voltage detection), and so it is able to achieve low VOL levels on both sides. It is p2p to the "DGK" package option of TCA9517, although switching to this device may need to impact other BOM items (for example, the device is intended to be operated without pull-up resistances). You can find out more about this device via the datasheet as well as this app note: www.ti.com/.../slva878.pdf.

    Please let me know if you have any further questions.

    Regards,
    Max
  • 0 in reply to Miguel Robertson
    Expert 2225 points
    Hi Max:

    To consider we have the PCA9306 (also I2C & SMBUS level shifter), do we have the solution to implement the function of TCA9802 into PCA9306's pin define?
  • 0 in reply to Kay Chen53
    TI__Guru 62920 points
    Hi Kay,

    That's an interesting idea, but I don't think TCA9802 could be considered a p2p replacement to PCA9306 even if the pinout were changed, since PCA9306 generally requires VREF2 and EN to be shorted together and pulled up to a reference voltage through a 200-kOhm current-limiting resistor.

    Max