• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 63 subscribers
  • Views 311 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.

TPS62150: Enable line and 400kR pull down

charge co
Prodigy 230 points
Part Number: TPS62150
Other Parts Discussed in Thread: TPS62147

Hi there

Could you clarify the following from the Enable / Shutdown (EN) section of the TPS62150 datasheet:

The EN signal must be set externally to High or Low. An internal pull-down resistor of about 400kΩ is connected and keeps EN logic low, if Low is set initially and then the pin gets floating. It is disconnected if the pin is set High.


Does this mean that the 400kR resistor is ALWAYS connected to ground? I'm assuming not, in which case if being driven from a microcontroller pin, before the pins have been setup they may be in an unknown state and an external resistor would be advisable, say 100kR?

Thanks

  • 0
    TI__Guru**** 150650 points
    Hi Charge,

    Yes, that's correct. The resistor is only connected if the pin is a logic low. If you have MCU pins that are floating until configured, an external pull down is probably appropriate.

    We also have the newer, smaller, more accurate TPS62147/8 to use instead.
  • 0 in reply to Chris Glaser
    Prodigy 230 points
    Perfect. Thank you. The new part looks interesting, is there any other downside apart from availability / cost with this new part?
  • 0 in reply to charge co
    TI__Guru**** 150650 points
    Being a 2A (vs. 1A) device with more features, it should be more expensive. You can also check with your PCB shop if they can put the vias on the center pins to pull out the heat. They are a little smaller than normal. It shouldn't be an issue with a 2A device, but without these vias TPS62147 will run a little hotter than TPS62150 which can easily have vias on its thermal pad.

    Otherwise, TPS62147 offers smaller size, a more accurate output voltage, forced PWM mode, VSEL function, precise EN pin, output discharge or hiccup current limit, etc.
  • 0 in reply to Chris Glaser
    Prodigy 230 points
    Thanks, it looks about the same price from TI and is more capable. I may bake it in...

    I can consider the issue resolve - thank you.