• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 506 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.

LP5569: Is the V1P8 pin really just a logic reference?

Ryan Rutledge57
Prodigy 30 points
Part Number: LP5569
Other Parts Discussed in Thread: LP55231

I started with the LP55231 on my project but realized I needed a sinking driver instead, so I ended up at the LP5569. There are many similarities but the most notable exception is V1P8 on the LP5569.

The datasheet says it is the "Input power for digital circuitry" but with current draw under 200 µA and none of the digital inputs limited to a value relative to V1P8, is it really just a logic reference for the digital circuitry rather than an actual power supply?

To make a long story short, I'll power the LP5569 from a 5V rail and I'm considering using a super cheap 1.8V reference for the V1P8 pin rather than a regulator, and leaving the I2C lines pulled up to the MCU's 3.3V logic. Is there any issue with this approach?

  • 0
    TI__Genius 12915 points

    Hi Ryan,

    Yes it is OK. V1P8 is the power line for internal digital circuits but the VIH and VIL for SCL/SDA pins is set at a fixed value. Just make sure your logic supply follow the requirement at datasheet section 7.8 Logic Interface Characteristics.