DP83640: Power Supply and I/O voltage question

Randy Wang

Part Number: DP83640

Hi Team

My customer is using DP83640 for design, and have some items to check:

1. If DP83640 IO_VDD is using 2.5V power supply, ANA33VDD is 3.3V, so MII, JTAG, GPIO, LED, CLK Input, RESET all is 2.5V?

And if JTAG is using 3.3V voltage, does it have any issue?

2. If IO_VDD using 2.5V, TD/ TR pull up voltage should be 3.3V or 2.5V? thanks.

over 8 years ago

0 Aniruddha Khadye over 8 years ago

TI__Mastermind 18425 points

Hi Randy,

MII, JTAG, GPIO, LED, RESET will work from IO voltage. So in your application they will be at 2.5V. Are you using a crystal for your clock input or a oscillator? If you are using a crystal you will not have to worry about clock input voltage.
JTAG should be a t 2.5V, since that is the IO voltage.

TD/TR pins should always be connected to 3.3V via 49.9ohm resistors as shown in the datasheet. This will not be dependent on IO voltage.

-Regards,
Aniruddha

0 Randy Wang over 8 years ago in reply to Aniruddha Khadye

TI__Intellectual 1705 points

Hi Aniruddha
Thanks for your comments, another question is: does oscillator should also be 2.5V? thanks.

0 Aniruddha Khadye over 8 years ago in reply to Randy Wang

TI__Mastermind 18425 points

Hi Randy,

You can use IO voltage (2.5V) for your oscillator in this case.

-Regards,
Aniruddha

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DP83640: Power Supply and I/O voltage question