• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 63 subscribers
  • Views 255 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS37F: Parameter : Hysteresis accuracy

Motoyasu Hattori
Genius 11095 points

Part Number: TPS37F

Hi,

PS37F010122DSKR device is 0.8mV threshold, Hysteresis 2% on both ch1 and ch2 as follows:

  • CH1 : OV OD H : 0.8mV(Typ)
  • CH2 : UV OD L : 0.8mV(Typ)
  • VHYS = 2% = 0.016mV (Typ) on both CH1 and CH2

What do you mean Hysteresis Accuracy on the datasheet P.7 as follows?

 

0.016mV*±1.5% distribution????   I am confusing.  Please let us know.

Thanks and best regards,
M.HATTORI.

  • 0
    TI__Guru 56345 points

    Hi M.Hattori-san,

    • CH1 : OV OD H : 800mV (Typ)
    • CH2 : UV OD L : 800mV (Typ)
    • VHYS = 2% = 16mV (Typ) on both CH1 and CH2

    I believe you had the wrong values for the threshold voltages.  Both threshold voltages are 800mV and the VHYS is 2% of 800mV which is 16mV.

    Therefore, for OV option, the threshold is 800mV (typ) for the output to assert and 784mV (typ) to deassert the output. 

    For UV option, the threshold is 800mV (typ) for the output to assert and 816mV (typ) to deassert the output.

    The hysteresis accuracy can be +/-1.5%.  If the 2% hysteresis accuracy is chosen, the worst case hysteresis can result in +/-0.5% which results in:

    OV: 796mV (4mV of hysteresis - worst case) to deassert the output

    UV: 804mV (4mV of hysteresis - worst case) to deassert the output

    Also, please see graph from TPS3704 to help you understand what I just mentioned.  The TPS3704 is a UV-OV window voltage supervisor where as the TPS37F is not a window voltage supervisor but an OV and UV 2-channel supervisor.

    I help my explanation above answers your questions.  Please let me know if you have any other question.

    Ben

  • +1 in reply to Ben C
    TI__Guru 56345 points

    Hi M.Hattori-san,

    I wanted to add one more bit of information regarding the hysteresis for TPS37B.  The TPS37B also has fixed hysteresis and the hysteresis is only available for thresholds up to 8V.  It is in the second row shown below where I have circled it in blue:

    Please let me know if you have any other questions.  If not, please click on "resolved" to close out the thread.  Thank you and good luck to you!

    Ben