topic Re: Unused USB pins in LPC Microcontrollers

Unused USB pins

jpowning — Thu, 13 Oct 2022 12:46:09 GMT

Regarding the USBn_3V3 pins, the datasheet says "Tie to VBAT_DCDC or connect to ground . If not using USB and using 1.8 V supply, USBn_3V3 can be connected to 1.8 V." This is confusing. If you are not using USBn, and it says it can be connected to ground, then why not connect it to ground (to minimize supply current)?

Re: Unused USB pins

ZhangJennie — Wed, 19 Oct 2022 11:51:55 GMT

Hi jpowning

What's the part number?

Thanks,

Jun Zhang

Re: Unused USB pins

jpowning — Thu, 20 Oct 2022 15:32:02 GMT

Hi - the part I am using is LPC55S16JBD100. Thanks for your interest.

Re: Unused USB pins

ZhangJennie — Fri, 21 Oct 2022 03:47:22 GMT

Please use the DS recommended design for unused USB pins. This is related with on chip HW design.

you should consider USB low power mode or disable USB domain to lower the power consumption.

Thanks,

Jun Zhang