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TPS2556/7 RILIM

Ryuuichi machida
Guru 11790 points
Other Parts Discussed in Thread: TPS2552D, TPS2556

Hi,

Let me confirm about below.

According to datasheet of TPS2552D/3D, there is following description about how to decide RILIM.

"Figure 23 includes current-limit tolerance due to variations caused by temperature and process.
However, the equations do not account for tolerance due to external resistor variation, so it is important to
account for this tolerance when selecting RILIM. The traces routing the RILIM resistor to the TPS255x and
TPS255x-1 must be as short as possible to reduce parasitic effects on the current-limit accuracy."

Datasheet of TPS2552D/3D : http://www.ti.com/lit/ds/slvs841f/slvs841f.pdf

However, when I check TPS2556/7 (these have low "Ron" resistance than TPS2552D/3D), I could NOT find above description in datasheet. 

Datasheet of TPS2556/7 : http://www.ti.com/lit/ds/slvs931a/slvs931a.pdf

So, could you please confirm whether "Figure 19. Current-Limit Threshold vs. RILIM" and caluculation formula of (1) of TPS2556/7 include current-limit tolerance due to variations caused by temperature and process or not ?

Best Regards,

Machida

  • 0
    TI__Expert 4055 points
    Hi Machida,
    Thank you for considering TI parts and please accept my apology that no one has followed up with your question. I have forwarded the question to our design team and will get back to you as soon as I get their reply. Again thank you for considering TI parts and sorry for the delay in responding to your question.

    Best regards,
    Haidar
  • 0 in reply to Haidar Hamoo
    TI__Mastermind 42795 points

    Machida,

    The curves of figure 19 are generated using curve fitting and Excel based on the guaranteed values for Ios given in the EC table of the datasheet. So, yes these curves use the MIN, TYP, MAX which include PVT given in the recommended operating conditions table.