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TL103WB: Use cases for OPA with built-in reference voltage

Conor
Mastermind 8930 points
Part Number: TL103WB
Other Parts Discussed in Thread: TL103W

Tool/software:

Hi,

Q1. Is there any comparison information between TL103W vs TL103WB?

Q2. I'm interested in use cases for OPA with built-in reference voltage. It seems that they are used in CC-CV control loops, etc. Other target applications seem to be switching power supplies/linear voltage regulation. Can you share some use cases for the TL103WB?

Thanks,

Conor

  • 0
    TI__Guru*** 143166 points

    Hello Conner,

    The B version is new and recommended replacement, so this is the version to use for new designs or old design in new projects. B has better offset voltage.

    Any time you need an op amp (even better two of them) and a voltage reference, TL103WB may be a convenient choice. The limiting factor is that reference has to connected to one amplifiers noninverting input. 

    I'll go with the data sheet's example use cases.

    • Battery chargers
    • Switch-mode power supplies
    • Linear voltage regulation
    • Data-acquisition systems
    • Precision constant current sink 

  • 0 in reply to Ron Michallick
    Mastermind 8930 points

    Hi Ron,

    Ron Michallick said:
    Any time you need an op amp (even better two of them) and a voltage reference, TL103WB may be a convenient choice. The limiting factor is that reference has to connected to one amplifiers noninverting input. 

    Thank you for the information about the reference applications.
    What specific cases do you envision where the reference would need to be amplified (especially in switching power supplies and linear power supplies)?

    Thanks,

    Conor

  • 0 in reply to Conor
    TI__Guru*** 143166 points

    Connor,

    Amplifying works when a second higher refence voltage is needed, but this is rare use for TL103

    Normally TL103 is used as an error amplifier, as called a null amplifier. The refence is a control signal. The other input is a variable input that is scaled to match the refence when it is the correct value. The output is an error voltage that brings the variable input back into balance. 

  • 0 in reply to Ron Michallick
    Mastermind 8930 points

    Hi Ron,

    I couldn't imagine it either, so I agree that the reference voltage is not often amplified. You mentioned using it as an error amplifier, but what are the advantages and disadvantages compared to using it as a comparator?

    The B version of the TL103WB has a price advantage, and I think it can also help make the entire system more compact. On the other hand, what are the disadvantages? Is the accuracy of VREF sufficient when using it as an error amplifier?

    Thanks,

    Conor

  • 0 in reply to Conor
    TI__Guru*** 143166 points

    Conor,

    In general op amps are not good comparators due the the slow propagation delay and rise/fall times. If that doesn't matter then they work fine.

    There are comparator versions of TL103 here; https://www.ti.com/amplifier-circuit/comparators/products.html#2192=Internal%20reference&

    For many applications, the accuracy of reference plus op amp Vos is good enough.