• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 64 subscribers
  • Views 141 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

TPS7B7702-Q1: Can you kindly help review the schematic diagram? Thank you!

user4645094
Prodigy 200 points
Part Number: TPS7B7702-Q1

Dears，

Can you kindly help review the schematic diagram? Thank you!TI_BUCK+LDO.pdf

  • 0
    TI__Expert 6570 points

    Hello, 

    I reviewed the schematics for T3 (TPS7B7702QPWPRQ1), T506 (TPS7B7702QPWPRQ1) and U39 (TPS7B8601BQDDARQ1). 

    What is your input voltage on all 3 of these devices? What current are you driving? What input voltage do you see on T3 and U39? It looked to me like they were both labeled 3, 12, 13. If this represents volts, 3V is too low for TPS7B7702-Q1 to regulate. 

    What output voltage are you looking for on U39? Its labeled as an adjustable device but I don't see feedback resistors. 

    Out 2 on T506 is labeled 9V, but based on your resistors I calculated 8.94. Is this the value you expect? 

    Please let me know if I can clarify anything,

    BR

    Erin

  • 0 in reply to Erin Thibeault
    Prodigy 200 points

    Hello，

    Reviewed the schematics for T3 (TPS7B7702QPWPRQ1), T506 (TPS7B7702QPWPRQ1) and U39 (TPS7B8601BQDDARQ1). 

    What is your input voltage on all 3 of these devices?

    Input voltage is 9V~16V for T3,T506,U39

    What current are you driving?

    U39<300ma.  T506 is 135ma for OUT1 and OUT2.  OUT1 of T3 is 300ma, OUT2 of T3 is 135ma

    What input voltage do you see on T3 and U39? It looked to me like they were both labeled 3, 12, 13. If this represents volts, 3V is too low for TPS7B7702-Q1 to regulate. 

    Input voltage is 9V~16V for T3,T506,U39

    What output voltage are you looking for on U39? Its labeled as an adjustable device but I don't see feedback resistors. 

    The output voltage of U39 is 5V.

    Out 2 on T506 is labeled 9V, but based on your resistors I calculated 8.94. Is this the value you expect? 

    Yes, we can accept 0.5V tolerance.

    Please let me know if I can clarify anything,

  • 0 in reply to user4645094
    TI__Expert 6570 points

    Hi,

    Thank you! I wanted to confirm that the devices do not exceed their maximum operating temperature.

    Based on power dissipation, both T506 and T3 should heat up about 48°C, and U39 should heat up 138°C. In your board design, I recommend distancing U39 from heat sources and providing thermal vias and additional copper to direct heat from the LDO. See this app note, An Empirical Analysis of the Impact of Board Layout on LDO Thermal Performance, for more information. 

    Please let me know what questions you have or if I can clarify anything. 

    BR,

    Erin