DP83867IR: Regarding the 1.8V power supply.

hiroshi.yamada

Intellectual 445 points

Part Number: DP83867IR
Other Parts Discussed in Thread: AM5708

Tool/software:

I'm connecting it to an AM5708.

I'm configuring it based on the circuit of the evaluation board below.

DRA71x/DRA79x/TDA2Ex17/AM570x CPU Board Schematic Rev D (Rev. B)

This configuration does not use 1.8V, but my circuit uses a 25MHz oscillator, so I need 1.8V as the oscillator power supply.

In this case, is it okay not to connect a 1.8V power supply to VDDA1P8?

I'm in a hurry as I'm currently in the design stage, so I would appreciate a quick reply in the comments.

Best regards,

Hiroshi Yamada

22 days ago

0 David (ASIC) Liu 22 days ago

TI__Guru**** 177071 points

Yamada-san

You can implement DP83867 two supply configuration in this case as shown below. The VDDA1P8 must be not connected.

Thanks

David

0 hiroshi.yamada 22 days ago in reply to David (ASIC) Liu

Intellectual 445 points

Hi David-san,

Thank you for your quick comment.

I understand that 1.8V is required for the oscillator, and that if you're not using 1.8V with VDDIO, you should not (should not) connect 1.8V to VDDA1P8.

Is this understanding correct?

Best regards,

Hiroshi Yamada

0 David (ASIC) Liu 21 days ago in reply to hiroshi.yamada

TI__Guru**** 177071 points

Yamada-san

Please see the table below, if any of these signals I/O voltage is 3.3V, then you can not set VDDIO to 1.8V. VDDIO voltage has to be set to 3.3V.

For XI oscillator voltage, it is between min of 1.5Vpp and max of 1.9Vpp.

Thanks

David

+1 hiroshi.yamada 21 days ago in reply to David (ASIC) Liu

Intellectual 445 points

Hi David-san,

Thank you for your comment.

VDDIO is connected to +3.3V.

The signals in the table also use +3.3V.

I understand the oscillator voltage. +1.8V is connected.

Best regards,

Hiroshi Yamada

Interface

Interface forum

DP83867IR: Regarding the 1.8V power supply.