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TL7702B: Power consumption of TL77xxB vs. TL77xxA

Mario Trams
Prodigy 40 points
Part Number: TL7702B
Other Parts Discussed in Thread: TL7702A, , TPS3700, TPS3710, TPS3702, TPS3701

Hello,

the data sheet of the TL77xxB specifies a quiescent power consumption of max. 3.5µA, while the data sheet of the TL77xxA specifies max. 3mA.

I'm not quite sure whether the specification for the TL77xxB is correct. 3.5µA would be rather low-power and on the TI website this device is not mentioned in the "Low power" category of the supervisory circuits. So I would assume that this is a typo and these 3.5µA are actually 3.5mA.

Any thoughts or experiences about that?

Thanks,

Mario

  • 0
    TI__Genius 12630 points
    Mario,

    The TL7702A was created in 1983 and TL7702B was created in 1989 so that could explain the improvement of Iq spec from version A to B. I can verify on the bench and let you know what I find.

    -Michael
  • 0 in reply to Michael_DeSando
    Prodigy 40 points

    Thanks for coming back on this, Michael.


    I doubt there has been done such a giant leap in those years. Especially when considering that we have today similar state-of-the-art devices with a power consumption in the 1 microamp area. So virtually nothing would have been happened since 1989.  But who knows....


    The TL77xxA/B had caught my interest because of the rather high allowable supply voltage.


    I also tried to simulate this with TINA, but unfortunately there are no models for this series included.


    In case my inquiry should lead to a correction of the data sheet of the TL77xxB here another unclear point I found: The functional block diagrams reference a "Note 1" regarding the voltage divider resistors at the sense input. The actual note seems to be missing (at least I didn't find it). The data sheet of the TL77xxA states the values of these resistors.

    Ciao,

    Mario

  • 0 in reply to Mario Trams
    TI__Genius 12630 points

    Mario,

    You are correct. It appears that when TI moved the TL7702B datasheet into the updated format, some of the notes & specs have been transcribed incorrectly. The Icc (supply current) spec has been confirmed to be the same numbers but incorrect units. The spec should read: 1.8 mA typical, 3 mA max for the condition when V_sense = 15V and RESIN >= 2V, and should read 3.5mA max for the full range. I have put in a request to fix this ASAP. If you notice anything else incorrect or missing please do not hesitate to inform me. Thank you!

    Also, our best wide Vin devices (Vin up to 18V or 36V options available) in terms of low power consumption is TPS3710 for undervoltage detection and TPS3700/TPS3701/TPS3702 for both undervoltage and overvoltage detection. These devices has supply current specs in the 5uA to 8uA range typical. Can I help you find the correct device for your application?

    -Michael

  • 0 in reply to Michael_DeSando
    Prodigy 40 points

    Hello Michael,

    thanks for your feedback and support!

    My application requires a timer function as well (more or less a standard power-on reset), ideally with a high supply voltage with up to 40V and no power consumption ;-)

    Anyway, I found a solution to go with a simple RC-combination for POR while overcoming the usual discharge-problem of the capacitor on a higher level with acceptable functionality. So I have got a solution with virtually no power consumption now.


    Thanks again nonetheless,

    Mario