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DP83869HM: Need Clarifications in Strap Configurations, Ferrite Bead Requirements, Unused Pins

Harikrishnan Thangamani
Prodigy 60 points

Part Number: DP83869HM

Hi Everyone,

Part Number: DP83869HMRGZT

Application of the device: 100BASE-TX and 1000BASE-T Ethernet Interface (SGMII to Copper Interface)

Strap Configuration Queries:

1) Is Functional Mode strap configurations are based on 2-Level Strap configuration resistor ratio (JTAG_TDO, RX_D3, RX_D2) ?

2) Is Auto-negotiation strap configurations are based on 2-Level Strap configuration resistor ratio (LED_0, LED_1, LED_2) ?

3) Is Mode 0 in 2-Level Strap configuration resistor means value is 0 for LED Pins and Mode 0 means 1 ?

Ferrite Beads:

Need Ferrite Bead Recommendations for power rails (Two-Supply Mode)

Unused Pins:

Recommendations for unused pins in the device whether it should be left floating or it needs to pulled up / down.

Unused pins in my configuration are JTAG Pins (Pin No 21, 23 & 24), TX_D(0:3) (Pin 25 - 28), TX_CLK (Pin 29),  TX_CTRL (Pin No 37), CLK_OUT (Pin No 40)

Please clarify mu doubts as soon as possible.

  • 0
    TI__Mastermind 19250 points

    Hi Harikrishnan,

    Harikrishnan Thangamani said:

    1) Is Functional Mode strap configurations are based on 2-Level Strap configuration resistor ratio (JTAG_TDO, RX_D3, RX_D2) ?

    2) Is Auto-negotiation strap configurations are based on 2-Level Strap configuration resistor ratio (LED_0, LED_1, LED_2) ?

    These statements are correct. Please place resistors according to table 9-7 in the datasheet. If you don't need to change the default strap value, you need not place any resistor.

    Harikrishnan Thangamani said:
    3) Is Mode 0 in 2-Level Strap configuration resistor means value is 0 for LED Pins and Mode 0 means 1 ?

    Mode 0 of 2-level strap is strap value 0 and Mode1 corresponds to strap value 1.

    Harikrishnan Thangamani said:
    Need Ferrite Bead Recommendations for power rails (Two-Supply Mode)

    There is no requirement. You can choose to have them for better EMC performance.

    Harikrishnan Thangamani said:
    Unused pins in my configuration are JTAG Pins (Pin No 21, 23 & 24), TX_D(0:3) (Pin 25 - 28), TX_CLK (Pin 29),  TX_CTRL (Pin No 37), CLK_OUT (Pin No 40)

    These pins can be left floating. Internal Pull-up/down resistors will take care of defining the voltages of these pins.

    --
    Regards.
    Gokul.

  • 0 in reply to Gokul Koraganji
    Prodigy 60 points

    Hi Gokul,

    Thanks for the information it really helps.

    I have two more queries with this part,

    1. Need recommendation for DO-160G Section 22, Level 3 & 4 Pin Injection Lightning Test.

    2. What lightning qualifications we are complying for the evaluation module ?

    Regards,

    Harikrishnan T

  • 0 in reply to Harikrishnan Thangamani
    TI__Mastermind 19250 points

    Hi Harikrishnan,

    DP83869HM is tested for EMC compatibility under IEC61000-x standards and not tested for DO-160G.

    If you can give me a correlation on what IEC standard the lightning testing corresponds to, I can check the performance of DP83869HM and let you know.

    --
    Regards,
    Gokul.