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TLK10232 - Power Requirements

Kawai
Guru 19785 points
Other Parts Discussed in Thread: TLK10232, TPS74401

Hi Team,

Our cusotomer is in design using TLK10232.
Could you please tell us about the power requirements for this device ?

There are several 1.0V power supply pins which are VDDA_LS/HS, VDDT_LS/HS, VDDD, DVDD pins.
Regarding the EVM schematic and pin desctiption, it seems that these pins must be powered from different power source.

[Question1]
In the EVM schematic 1.0V power supply pins are all powered from LDOs.
Is this must for TLK10232 power design or is it possible to use DC/DC converters ?

[Question2]
I believe that these pins (VDDA_LS/HS, VDDT_LS/HS, VDDD, DVDD) need to be powered from separate power source regarding the EVM schematic.

However, customer is considering to use common power supply. Is it possible to use common power supply for VDDA_LS/HS and VDDT_LS/HS (Analog Power), also VDDD and DVDD (Digital Power) such as below ?

DC/DC1 or LDO1 ---------> VDDA_LS/HS and VDDT_LS/HS
DC/DC2 or LDO2 ---------> VDDD and DVDD

[Question3]
Could you please tell us other requirements or anything else we should take care about for TLK10232 power design ?

Best Regards,
Kawai

 

  • 0
    TI__Mastermind 20820 points

    Hi Kawai,

    1. The TLK10232 can be powered from an LDO or a DC/DC converter. We chose to use LDOs on the EVM because LDOs typically have less output noise than DC/DC converters.

    2. VDDS_LS/HS. VDDT_LS/HS, VDDD, and DVDD do not need to be powered by separate sources. A common power supply is fine to use with the TLK10232 as long as the LDO or DC/DC converter can supply there required amount of power to the IC.

    All four rails can be combined in one power supply or they can be split into whatever configuration that is convenient for the customers application.

    3. We do not use any inductors on the EVM because our power supplies are really clean but if the customer suspects that their will be excessive noise present in the their system they could implement inductors to help filter out the high frequency noise. Also make sure the caps are placed as close to the pins as possible on the TLK10232 and the power supplies.

    Please let me know if you have any questions?

    Regards,

    Michael Peffers

    Analog Applications Engineer

  • 0 in reply to Michael Peffers
    Guru 19785 points

    Hi Michael-san,

    Thank you for your prompt reply. Your comments helps us very much.

    Could you please let me ask you 2 more questions ?

    In the USER GUIDE(SLLU180) schematic page 17, I found the description, "Must use TPS74401 3A LDO" for VDDD.

    [Question4]
    Could we change this LDO to DC/DC, combine all four rails to one ?

    [Question5]
    Why do you recommend to use 3A LDO for VDDD rail ?
    As the maximum supply current is 650mA, I believe we could use 1A power supply device. 

    [Question6]
    I understand we may need to filter the power supply using ferrite beads if we use DC/DC.
    However, we would like to know how we can judge if the designed DC/DC could be used or not.
    Could you give us youre advice ?

    Currently our customer do not have in mind to use LDOs for TLK10232.

    Best Regards,
    Kawai

  • 0 in reply to Kawai
    TI__Mastermind 20820 points

    Hi Kawai,


    The note on page 17 of the schematic is meant for our board house because sometimes they would substitue a 1.5A LDO for 3A LDO and not tell us.

    4. Yes

    5. A 1A power supply will be fine.

    6. If your power supply is noisy it will add more jitter to your system. Unfortunately there is not really a good measure of this that I can give to guide you. It depends on what the customers system can tolerate and how clean the reference clock is. The engineers should use their best judgement when designing the power supply.

    Regards,

    Michael Peffers

    High Speed Interface Applications Engineer

  • 0 in reply to Michael Peffers
    Guru 19785 points

    Hi Michael-san,

    I understood.

    Thanks for your great help !

    Best Regards,
    Kawai