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TPS7A66-Q1: PG pin Sink Current Capability

hideyuki sakai
Mastermind 6250 points
Part Number: TPS7A66-Q1

Dear, Sir. 

My customer is evaluating TPS7A6650-Q1 for their system. 

They faced EMC(immunity) issue, then find the solution as change PG pinpull-up resistor value

from 10kOHM to 1kOHM. 

Now, they are asking about PG pin sink current capability because it is unclear on the datasheet. 

Please give your advice. 

1. Sink Current Capability. 

    Please clarify PG pin sink current capability and Please give your advice it is no problem 

    to change the pull-up resistor value from 10kOHM to 1kOHM. 

2. Influence to VOL. 

  I suppose the decrease of pull-up resistor value will cause the VOL level rising up due to sink

  current increase. The datasheet looks defining VOL=0.4V under IOL= 0.5mA.(It mean that Ron of

  internal transistor will be 800OHM. I think it will be huge )

  So, I would like double-confirm that ; 

  Is VOL = 0.4V really defined under IOL = 0.5mA(10kOHM pull-up to 5V output)?

Best Regards, 

H. Sakai

 

  • 0
    TI__Expert 7015 points
    Hi Hideyuki,

    The Vol is tested by using a current source to force current into the node and then the voltage is measured. You are correct that the max Ron would be 800 ohms. This may present a problem using a 1k resistor. I would recommend that you use a 10k-100k resistor on the PG pin due to the high on resistance. Unless you can tolerate the higher logic low output in your system.

    Have you tried connecting PG to a different rail in your system? If you have does it have any effect on the device performance, are you able to pass EMI testing?

    Best Regards,
    Mark