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PGA411-Q1: Maximum Supply Current of PGA411-Q1

Yazhu Liu
Intellectual 1410 points
Part Number: PGA411-Q1

Hi Team,

May I ask the maximum allowed current of supply rail VCC, VIO, QVCC, VCCSW and VEXTS?

In customer's system, VIO=5V, VEXT=12V.

Thanks.

Best Regards,

Livia

  • 0
    TI__Expert 7599 points

    Hi Livia,

    The maximum current is going to be the combination of all the supplies combined and also includes the Exciter supply. The largest would be the Exciter supply which the device is capable fo supporting a maximum of 145mA. The VIO and VCC are typically low current voltage nodes. 

    I suppose your question would be in regards to maximum current supported so to pick the appropriate external supply ? I would recommend a minimum of 1A or higher to account for any transients. 

    Also, the datasheet does describe that there be a sequence between VIO and VCC I would recommend that VCC and VIO not be connected to the same voltage rail as it does require sequencing. 

  • 0 in reply to Arjun_Prakash
    TI__Intellectual 1410 points

    Hi Arjun,

    Thank you for the quick support.

    Customer is doing a new design with PGA411-Q1 and considering cost and size requirement, they do not want to use 2 power rails for VCC and VIO, and the have several questions regarding this:

    1. Why PGA411-Q1 require VCC ready before VIO? I guess it's because the core should be powered before I/O? 

    2. It says in the datasheet that "VIO should never be supplied before VCC is stable", does this mean VIO should stay 0V before VCC reach 5V? But datasheet also says we can use current limit resistor so I assume the requirement is not so strict? Is it ok for customer to make VIO rise along with(but slower than) VCC?

    3. For the current limit resistor, do we have any suggest value/package? Is there any need to add a capacitor?

    4. Can we use bead(spec as below)+capacitor instead of current limit resistor?

    Thanks again.

    Best Regards,

    Livia

  • 0 in reply to Yazhu Liu
    TI__Intellectual 1410 points

    To add that, customer choose our LDO https://www.ti.com/product/TPS7B4253-Q1 to power VCC/VIO, its maximum Iout is 300mA, not up to 400mA.

    Best Regards,

    Livia

  • 0 in reply to Yazhu Liu
    TI__Expert 7599 points

    Livia,

    As we are discussing offline I want to close this thread and emphasize that a sequence is a must as described in the datasheet. 

    Thanks,