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.
Hi
I have a question about magnetics connections of DP83867.
I am looking at EVM schematic #DP83867ERGZ EVM: http://www.ti.com/lit/df/snlr034/snlr034.pdf
Acording to the schematic, the following is magnetic-connections.
I wonder why Positive and Negative pins are reversed.
[DP83867] --- [TRANS] ------------[RJ45]
TD_1_P --- TD4-(Negative)
TD_1_N --- TD4+(Positive)
Are there any reason for this? My customer need to do such schematic design? (P and N pins have to be reversed?)
I think, either one is OK. Because this magnetic is not use for the voltage transformer but the isolation transformer and reduction EMI. Is my understanding correct?
Best Regards,
Taka
-----------
5/31/18[LE]>unlock
Hi Ross,
Thank you for your reply. I got it.
Excuse me, I have one more question about DP83867ERGZ EVM RJ45 Connection.
I know that the EVM is using Mirror mode to connect to RJ45. So, I understand it makes reorder the port.
A → D
B → C
C → B
D → A
However, The channel Polarity is reversed, too.
For example:
TD_1_P --- TD4-(Negative)
TD_1_N --- TD4+(Positive)
Can the Mirror mode revrese the "Channel Polarity"? Not only "Port"
Best Regards,
Taka
*EDIT w/ new information*
Hi Taka-san,
Mirror mode changes the polarity and reorders the port numbers as well.
Pin # (48QFN) | Mirror Mode Disabled Pin Assignment | Mirror Mode Enabled Pin Assignment |
1 | TD_P_A (A+) | TD_M_D (D-) |
2 | TD_M_A (A-) | TD_P_D (D+) |
4 | TD_P_B (B+) | TD_M_C (C-) |
5 | TD_M_B (B-) | TD_P_C (C+) |
7 | TD_P_C (C+) | TD_M_B (B-) |
8 | TD_M_C (C-) | TD_P_B (B+) |
10 | TD_P_D (D+) | TD_M_A (A-) |
11 | TD_M_D (D-) | TD_P_A (A+) |
This should not present an issue because DP83867, and all gigabit PHYs, automatically detects and corrects polarity of the channel. The polarity detection and correction feature does not have to be managed.
Best Regards,