DP83TC811S-Q1: DP83TC811S-Q1 application issue

Eric Shen42

Part Number: DP83TC811S-Q1

Dear TI engineer:
There are 5 problems of DP83TC811S-Q1, please help to answer:
1, If my customer use SGMII interface, need set MAC(2-0) :000

And the 4 level bootstrap as below, does it mean SMGII interface only in Mode 1(RX_P, RX_M)?

Can customer used the resister to set the mode of RX_P and RX_M? Does the MAC interface and Strap mode conflict?

2, How to in sleep mode? Does only need set sleep enabled to “1”? How the "wake" pin set, pull low?

4, What is the max run rate of TRD_P/N?

5, Why MDIO pull-up register is 2.2K to 9K?

Thanks!

over 7 years ago

0 Rob Rodrigues over 7 years ago

TI__Mastermind 19780 points

Hi Eric,

1. Yes, the DP83TC811S defaults to SGMII 4-wire mode.

2. We are planning to post a low power mode app note next week. Please check for it by Wednesday 5/2

4. The guaranteed reach of the TRD_P/N MDI of the device is 15m as specified in the IEEE standard. In our lab we have tested beyond 30m using typical automotive STP cables.

5. I personally recommend you use a 2.2k resistor with the MDIO line. Some systems have shown with low clock rate, a 9k pull-up is OK. A 9k pull-up may also reduce emissions from fast edges driven by the 2.2k resistor.

Best Regards,

0 Eric Shen42 over 7 years ago in reply to Rob Rodrigues

Expert 2750 points

Hi Rob：

The fourth problem, customer need to selected ESD device, so can you help to check the max run rate of TRD_P/N?

The first problem : "Can customer used the resister to set the mode of RX_P and RX_M? Does the MAC interface and Strap mode conflict? " Please help to check again.

Thanks!

0 Rob Rodrigues over 7 years ago in reply to Eric Shen42

TI__Mastermind 19780 points

Hi Eric,

The edge rate of the TRD_P/N is 15ns - 18ns

Yes, the register can set the mode of RX_P and RX_M. MAC interface strap only only sets initial operating mode. Operating mode can be changed later. There is no conflict if setting does not match strap.

Best Regards,