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BQ2946: Details on OUT pin

Phil2010
Expert 4735 points
Part Number: BQ2946

Hi,

couple of questions regarding the OUT pin of BQ294602:

1) In the datasheet, we specify in test item 1.14 the current for Iout(short) with typical 1.5 mA, max 3 mA. Does this mean that the device is able to drive this current reliably? Or does this mean that the external circuitry must ensure to never exceed these values? What would happen if this pin observes a short to VSS while the device drives it high?

2) What happens if the OUT pin drives low and one was to apply a higher voltage? Would this damage the device? Is there an internal ESD structure that would feed an applied voltage e.g. to VDD (or similar)?

Best regards,
Phil

  • 0
    TI__Guru 54715 points
    Hi Phil,
    1. The short circuit output current is the current the part can deliver into a short circuit. Most will provide 1.5 mA, some parts under some temperature and voltage conditions may be able to provide as much as 3 mA. The output could provide less current when shorted, a minimum is not specified. It will meet the voltage at 100 uA shown in 1.11.
    2. A sink current is not specified, nor is an abs max current. The voltage and power specification must not be exceeded. I will look for additional information.
  • 0 in reply to WM5295
    TI__Expert 4735 points

    Hi,

    does this mean OUT will be damaged if one applies a short to VSS? I understand that the pin will not be able to drive high under such condition.

    Best,
    Phil

  • 0 in reply to Phil2010
    TI__Guru 54715 points
    Hi Phil,
    Still checking.
  • 0 in reply to WM5295
    TI__Guru 54715 points
    Hi Phil,
    OUT is not damaged by short circuit. OUT has an internal resistance of about 3k when driving high and will output a current when shorted, the data sheet shows a limit for the conditions stated. Power in the IC must be limited to the specification limit.
    When low, OUT will pull down with an internal resistance approximate 2.5k.
    When driving low OUT does not send current to VDD, but when high pulling OUT above VDD will pull up VDD.