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REG1118: Current Source and Sink Capability LDO

Milan Parekh
Prodigy 20 points
Part Number: REG1118
Other Parts Discussed in Thread: TPS723, TPS7A3401, TPS7A30

Tool/software:

Hello Sir,

Hope this message finds you well,

I have few questions mentioned below, it will be appreciated if you provide your inputs here.

1) Can you please suggest some more LDOs with Current Source and Sink Capability with feature of run time programable and Enable feature support?

2) Can you please share some documents related to LDO current source and sink capability Understanding.

3) Please share some LDOs with Negative Sink current ~100mA capability.

4) Can you please share some reference design to run time program LDO output.

Thank you in advance

Regards,

Milan Parekh

  • 0
    TI__Mastermind 34125 points

    Hi Milan,

    We are trying to direct your request to the correct team within TI.  Do you need a device like this termination regulator? Typical LDO's and linear regulators do not sink current, but termination regulators do.

    https://www.ti.com/product/TPS51200

    Thanks,

    Stephen

  • 0 in reply to Stephen Ziel
    Prodigy 20 points

    Dear Stephen,

    Thank you so much for your quick support. Actually, we have first time got Sinking Regulator requirement from our customer, so we are completely new in that perspective. So sorry for unable to judge here whether Termination Regulator will help us in our case. 

    Below is our requirement for High Precision LDOs.

    Can you please share us recommended TI Parts and Circuit reference for our below requirements? Your valuable guidance will help us lot to move quickly.
    You can share us TI App notes and Reference Designs for our internal study in this regard. 
    LDO 1 -
    Voutput : +5VDC
    Ioutput (Sink) : 100mA
    Ioutput (Source) : 120mA
    LDO 2 -
    Voutput : -1.5VDC
    Ioutput (Sink) : 60mA
    Ioutput (Source) : 100mA
  • 0 in reply to Milan Parekh
    TI__Mastermind 18990 points

    Hi Milan,

    As far as I know there are only a few devices that may fit your needs, and I don't think they have any programming capability. The settings are determined by hardware (resistor dividers on certain pins).

    TPS51200

    TPS51206

    TPS51116

    LP2998

    Unfortunately, I don't think any of these devices is capable of outputting both positive and negative voltages and I don't think they can support +5V. The specifications you have provided are not something I usually see. If the LDO team didn't have a recommendation, then we may not have a part to support that specific system requirement (especially if you need real time programming).

    Regards,

    James

  • 0 in reply to James Steenbock
    Prodigy 20 points

    Dear James,

    Thank you so much for your valuable support. 
    We don't require outputting positive and negative voltages from same regulator part number so that's not an issue. 

    We will allocate individual LDOs based on requirement of Positive and Negative voltage requirements. Kindly suggest negative outputting LDO part numbers with Source/Sink function including reference design. You can consider negative supply input for the same as per below specification.

    Vinput : - 3.3VDC
    Voutput : - 1.5VDC
    Ioutput (Sink) : 60mA
    Ioutput (Source) : 100mA
  • 0 in reply to Milan Parekh
    Prodigy 20 points

    Dear James,

    Hope you have received below email.

    Your earliest response will help us lot for part finalization.

  • 0 in reply to Milan Parekh
    TI__Mastermind 34125 points

    Hi Milan,

    LDO's which can both sink and source current are called DDR termination regulators.  They are positive regulators.  A search on distributors such as digikey reveal that these regulators come in positive input and output options, but not negative.

    • Standard positive LDO's can source current but not sink current.  Positive LDO's provide positive current that flows out of the OUT pin (thus, sourcing current).
    • Standard negative LDO's can sink current but not source current.  Negative LDO's provide negative current that flows into the OUT pin (thus, sinking current.)

    We have negative LDO's but they do not both sink and source current.  Options exist that only sink current include the TPS723, TPS7A30, and TPS7A3401.  Can you help us understand what the application is that needs to both sink and source current with a negative rail?

    If no options exist (very likely) but you still need to sink / source current for your negative LDO, we can probably devise a simple circuit to do this for you using our negative LDO to sink the current and another simple circuit to source current when the right conditions exist.

    Thanks,

    Stephen

  • 0 in reply to Stephen Ziel
    Prodigy 20 points

    Dear Stephen,

    Thank you so much for your valuable support.

    I will discuss with my team in this regard and get back to you soon on Monday.