• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 63 subscribers
  • Views 431 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.

TPS7A60-Q1: LDO device recommendation

Gene Qiu
Intellectual 1720 points
Part Number: TPS7A60-Q1
Other Parts Discussed in Thread: TPS7B82-Q1, TPS7B63-Q1

Here wants a TI LDO recommendation to power the DSP, with requirements: 15V Vin to 5V Vo, Io=250mA, no matter quiescent current performance, just want better heat dissipation performance, since the device's ambient temperature would rise to 80 degree Celsius and the power loss is 2W. 

Is TPS7A60-Q1 good choice for this case ? Thx  ^_^

  • 0
    TI__Guru 55940 points
    Hi Gene,

    For this application we would typically recommend TPS7B63-Q1 or TPS7B82-Q1. As you note, this application has a large power dissipation. In order to improve the performance of the LDO, a power resistor could be placed in series before the LDO. This would spread the power dissipation and allow the LDO to operate at a lower junction temperature than if all the power were to be dissipated with the LDO.

    Keep in mind that the primary heatsink for these LDOs is the GND plane. As such it is important to maximize the GND plane connected to the LDO when you move toward laying out your PCB.

    Very Respectfully,
    Ryan
  • 0 in reply to Ryan Eslinger
    TI__Intellectual 1720 points
    Thank you for you reply! What you mentioned is quite helpful with power resistor placed in series before LDO.
    One more question: do we need to consider the RθJA Junction-to-ambient thermal resistance, since TPS7A60-Q1 is 25 °C/W, lower compared to TPS7B63-Q1 (40 °C/W )?
  • 0 in reply to Gene Qiu
    TI__Guru 55940 points
    Hi Gene,

    It is a good idea to still consider the thermal metrics; however, it is important to keep in mind that the thermal metrics are modeled on a JEDEC High-K board. The actual thermal performance of an LDO will vary with application specific factors such as layout and proximity to other heat sources.

    By using an external power resistor to dissipate some of the power, you can likely make up for the delta in theta JA between TPS7A60-Q1 and TPS7B63-Q1. Our recommendation for your application is TPS7B63-Q1 for better performance and ease of design. Keep in mind that since TPS7B63-Q1 has a lower minimum Vin, you can place a larger power resistor before TPS7B63-Q1 to dissipate more power in the resistor before the LDO.

    Very Respectfully,
    Ryan