• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 63 subscribers
  • Views 528 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.

WEBENCH® Tools/LP38798: Webench still connects VIN to the EN pin directly, even if VIN is above 5.5V

Bart Smienk
Prodigy 60 points
Part Number: LP38798

Tool/software: WEBENCH® Design Tools

Hi

There is a error in webench regarding the automatic schematic creation of LP38798-ADJ (And possibly the non adjustable too, I haven't checked)

I'm using the following design variables:
VinMin: 14.4V
VinMax: 15.6V
Vout: 13.5V
Iout: 0.2V

In the generated schematic the webench connects the input (VIN) directly to the EN pin. However since there is a zener diode internally this can not be done for voltages above 5.5V (As described in the datasheet of the LP38798). VIN in my case is way above 5.5V
The webench application should've not put any connection to the EN pin because its internally pulled up or should put a 2Mohm resistor between VIN and EN to lower the power to about 7.5uA

Just letting someone of Ti know to change this, cheers!

  • 0
    TI__Intellectual 1490 points

    Hi Bart ,

    Thank you for reporting the issue. You are correct about the error in the WEBENCH schematic and you are also correct about the resolution - either keep EN open or have a large resistance connected between EN  and VIN. We will update the schematic in WEBENCH to fix this issue.

    Best Regards,

    Srikanth Pam | Online Design Tools