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About TPS51372 IC's electrical specification

Norimichi Hosogai
Prodigy 230 points
Other Parts Discussed in Thread: TPS51372

About TPS51372, Is above case, we must be think that input voltage 3V- 0.8V=2.2V? or 3V directly?

We adjust port's voltage to 1.6V or more for keep Vth(H) specification.

Best regards,

  • 0
    TI__Genius 16632 points

    Hi Hoso,

    Thanks for reaching to us!

    The red circles you pointed are test conditions, not test results. If you want to enable the device, please maker sure VEN > 1.6V.

    Let me know if you have further questions.

  • 0 in reply to Miranda Gu
    Prodigy 230 points

    Thank you for youre help.

    By the way, I have questions. Could you teach the below as soon as possible, please?

    (1). About the R1 VBST series resistor's rated power, Is it 63mW no problem?   

    (2). About C0/C1/LP# port, is pull up 3.3V 20kohm no problem?

    (3). About C0/C1/LP# port, is pull down 20kohm no problem?

    Best regards

  • +1 in reply to Norimichi Hosogai
    TI__Genius 16632 points

    Hi Hosogai,

    1. Yes, it's 0ohm resistance, power loss is almost zero, you can use 63mW rating resistor.

    2. I don't see problems.

    3. I don't see problems..

  • 0 in reply to Miranda Gu
    Prodigy 230 points

    Thank you for your help.

    I have question.

    (1). About C0/C1/LP# port, this port has 2uA constant current pull down as TPS51372 datasheet.

    Therefore, if  do set C0/C1/LP# port  to Low level, external pulldown resistor is unnecesarry? Is it correct?

    Or external pulldown resistor connect is recommended? If external pulldown resistor connect is recommended,  

    please teach the reason and recommended resistor value, please?

    (2).  When do set C0/C1/LP# port  to High level,

    Could you teach the recommend pullup voltage, please? Is it 3.3V correct? Or other?

    Besides, please teach the external pullup resistor value calculation method. Is it 3.3V - (2uA×external pullup) > 1.6V, correct?

    Best regards,

  • +1 in reply to Norimichi Hosogai
    TI__Expert 7320 points

    Hi Hosogai,

    Because CO/C1/LP# pin is the input pin, you can understand that their input impedance is very large.

    (1) Yes. You can remove the external pull down resistor.

    If you use a pulldown resister, you can ground the pin more reliably.

    While choose the pulldown resister, just be careful not to use a resistor with too small value to avoid the effect of GND disturbances on the pin voltage. Usually we choose 1k-100k.

    (2) About the pullup voltage, you should ensure that pin voltage > 1.6V.

    So 3.3V is correct and your formula 3.3V - (2uA×external pullup) > 1.6V is also correct.

    The max input voltage is 6V, so make sure pullup voltage < 6V.

    As for the external pullup resistor, make sure Vcc - (2uA×external pullup) > 1.6V. Usually we choose 10k-100k.