• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 63 subscribers
  • Views 918 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.

Query reagrding TPS7A7100, TPS7A7200 & TPS7A7300 (RGW Package)

Justin Thomas
Prodigy 100 points
Other Parts Discussed in Thread: TPS7A7100, TPS7A7300, TPS7A7200

Hi,

We are using the above mentioned regulators (RGW package) on our board.

In the revised datasheet (Jan2013) it is mentioned to connect  a 220-pF ceramic capacitor (CFF) from FB pin to OUT for TPS7A7100 and TPS7A7200 but nor for TPS7A7300.

And in " TPS7A7100 and TPS7A7200" they have mentioned CFF = 0pF for RGW package and CFF = 220pF for RGT package in electrical characteristics sheet (pg 4 in datasheet)

So my doubt is as we are using RGW package regulators do we have to connect 220pF capacitors across FB and Out pin. 

Pls see a snapshot of a power supply section used on our board. We are leaving the FB pins open here.

  • 0
    TI__Mastermind 41770 points

    Hi Justin,

    A CFF capacitor is not required for stability. However, having a 220pF CFF can improve transient performance and noise. The circuit above is still a valid design.

    Regards,

    Darwin

  • 0 in reply to Darwin Fernandez
    Prodigy 100 points

    HI Darwin, 

    Thank for the reply.

    My doubt is why for RGW package CFF is mentioned as 0pF and for RGT package 220pF. Any reasons?

    Anyway on our board we are using RGW package and as mentioned as CFF = 0pF in data sheet, we are going without CFF capacitor between FB pin and Out pin 

    Hope this is fine....

    Regards

    Justin

  • 0 in reply to Justin Thomas
    TI__Mastermind 41770 points

    Hi Justin,

    It will be fine. The RGW and RGT devices perform the same and is stable with or without a capacitor. We were able to optimize transient perfromance with a feedforward capacitor using the RGT package for a specific customer so it was added to the datasheet. Having a feedforward capacitor on the RGW will also optimize transient response but is not needed.

    Regards,

    Darwin