• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 33 subscribers
  • Views 608 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TCA9554A: What is leakage from SDA/SCL to Vcc when device is unpowered & SDA/SCL is pulled up to 3.3V?

Ronnie Hughes
Expert 3090 points
Part Number: TCA9554A


If the TCA9554A is not powered on VCC, but inputs (specifically SCL and SDA) are pulled up to a 3.3 volt standby supply via a pull-up resistor, what amount of current leakage will occur to VCC?

The datasheet indicated that if SCL or SDA is at a higher potential than VCC, the leakage current (IsubL) will increase above the +/- 1 mA level, but is it not clear what the leakage amount will be and if the path is to Vcc, to GND, or to both.

 

  • 0
    TI__Guru 74811 points

    Hey Ronnie,

    "The datasheet indicated that if SCL or SDA is at a higher potential than VCC, the leakage current (IsubL) will increase above the +/- 1 mA level"

    Can you point out where you see this? I do see a leakage current spec'd at 1microamp in the datasheet, did you mean +/-1uA?

    Our device should be high impedance when the Vcc of the device is unpowered, even when there is a pull up resistor to a powered rail on SDA/SCL. I wouldn't expect leakage current to be as high as 1 mA unless you pulled the SDA/SCL pins above ~7V and put some body diodes into reverse breakdown or started to power an ESD cell.

    -Bobby

  • 0 in reply to BOBBY
    TI__Expert 3090 points

    Bobby, sorry typo on my end. I meant 1 uA.

  • 0 in reply to Ronnie Hughes
    TI__Guru 74811 points

    Hey Ronnie,

    Just wanted to check. Did my earlier post answer the question you were asking?

    Thanks,

    -Bobby