DP83TG721S-Q1: Voltage step on RESET pin

Jass Jin

Part Number: DP83TG721S-Q1

Tool/software:

Hi expert,

Here is my schematic. If we disconnect reset pin with MCU, 10ms after VDDIO, we can see a 650mV voltage step on reset pin.

This is strange and looks like a leakage current, is it normal for this device?

8 months ago

0 David Creger 8 months ago

TI__Mastermind 26932 points

Hi Jass,

RESET_N pin has internal 9kohm pullup resistor. This is shown in table 6-2 of datasheet. The voltage you see on the reset pin is the voltage divider of PHY internal pullup and your 10kohm pulldown. MAC must drive RESET_N high in this case in order to release PHY from reset. Or you may remove the pulldown resistor R2565.

Thanks,

David

0 Jass Jin 8 months ago in reply to David Creger

TI__Intellectual 2475 points

Hi David,

We cannot access to the latest datasheet, the file in secure folder is only a draft and updated in June 2024.

The draft version does not have table 6-2.

Thanks!

+1 David Creger 8 months ago in reply to Jass Jin

TI__Mastermind 26932 points

Hi Jass,

June 2024 is the latest version of the datasheet, it is not a draft version.

It is table 5-2 in the June 2024 datasheet, my apologies.

Thanks,

David

Interface

Interface forum

DP83TG721S-Q1: Voltage step on RESET pin