• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 62 subscribers
  • Views 272 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.

UCC2807-2: Start threshold Max is same as Absolute Maximum Supply Voltage

Jim Brinkhurst1
Mastermind 44680 points

Part Number: UCC2807-2

Hi experts

From the datasheet, the Max value for the Start Threshold is 13.5V. This is the same voltage listed as the Absolute Maximum Supply Voltage for the part.

How can we guarantee we start up the device correctly, without applying a voltage that is at or above the Absolute Maximum Supply Voltage, and potentially damaging the part?

Thanks,

Jim B

  • +1
    TI__Guru 74075 points

    Hi,

    In typical applications, you can tie a resistor (startup) from VDD to the Vin and a capacitor from VDD to GND for startup. So the capacitor will be charged up and when VDD voltage reaches up to 13.5V, the IC will start to work. For VDD current, the startup current (max 0.25mA) and the normal operation current (max 2.1mA), so right after startup, the VDD voltage will drop and < 13.5V if you design the startup resistor with 0.25mA or so due to a much higher current will present right after startup. Your aux biasing voltage can be designed between 9V and 12.5V to leave some room from 13.5V.