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TPS51216-EP: Questions about using TPS51116-EP & TPS51216-EP for a DDR3L application

umutk
Prodigy 60 points
Part Number: TPS51216-EP
Other Parts Discussed in Thread: TPS51116-EP, TPS51216, TPS51116, TPS51716, TPS51916

Hi, 

I am thinking about using TPS51116-EP or TPS51216-EP controllers for a DDR3L application. I need a design that works at 105°C ambient temperature and I have limited space. Plus I have a tight voltage regulation requirement(+-3% for VDDQ).

My questions are:

1) Is there a better alternative for such application (I have 12V input voltage b.t.w) 

2) My VTT output has to supply 1A at 0.675V. Thermal characteristics of TPS51116-EP is better than TPS51216-EP (one has 41.2°C/W RθJA while other has 94.1). I have concerns about thermal management if I use TPS51216-EP. What do you recommend?

3) Can I use TPS51216-EP with all-ceramic output capacitors if I implement the ripple injection method described in SLVA453 aplication note? 

4) Is there formula to calculate necessary output capacitance to meet a load transient requirement in DCAP based controllers?

5) I am assuming TINA models for TPS51116 and TPS51216 are same for -EP coded devices. Is it correct?

Thanks in advance.

  • 0
    TI__Mastermind 24075 points

    Hello, 

    1. From thermal perspective, TPS51116 is the best choice because its thermal impedance is lower than TPS51216 or TPS51716. 

    2. Both TPS51116 and TPS51216 use bottom thermal pad to dissipate almost all heat. We should look at "junction to board" or "junction to bottom case" thermal data, not junction to ambient.  

    3. I think it is doable. Another option is use TPS51716 or TPS51916 which have DCAP2 options for all ceramic Cout. 

    4. Simulation is suggested for load transient. 

    5. No sure. Just use the model of the part you are interested. 

    Thanks

    Qian

  • 0 in reply to Qian Chen
    Prodigy 60 points

    Hi Qian, 

    Thanks for the quick reply. I have already looked up TPS51716 or TPS51916 but their operating temperature range do not meet my need (operation at 105C ambient temp).

    I am inclined to use TPS51116-EP but I couldn't find a SPICE model for TPS51116-EP. Can you help me with that?

    (There is a transient model given in design tools and simulation tab of TPS51216-EP, -EP extension is missing though, that's the reason for my assumption)

    Best regards,

    Umut

  • 0 in reply to umutk
    TI__Mastermind 24075 points

    Hi Umut, 

    The TPS51116 pspice transient model is available at below link.

    https://www.ti.com/product/TPS51116#design-development

    Thanks

    Qian