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TPS568215: TPS568215RNNR

Ashvin Patil
Prodigy 30 points
Part Number: TPS568215
Other Parts Discussed in Thread: TPS54J061, TPS54JA20, TPS548A28, TPS543B20, TPS543820, TPS543A26

Hi,

we are choosing part TPS568215RNNR for our design having following requirements,

1) For 3.3V output

Vin = 5V

Iout =  2A (actual continuous load)

Total Capacitance load = 1175 uF (considering all decoupling capacitors)

2) For 1.8V output

Vin = 5V

Iout =  1A (actual continuous load)

Total Capacitance load = 120 uF (considering all decoupling capacitors)

3) For 1V output

Vin = 5V

Iout =  2A (actual continuous load)

Total Capacitance load = 120 uF (considering all decoupling capacitors)

We need following thing,

1) Whether selected buck converter is good to go.

2) Require EMI-EMC reports/graph for the same.

3) Any EMI filter to be added to make it EMI compliant.

4) In simulation (Webench), how to add capacitive load as per our need?

Thank you.

  • 0
    TI__Mastermind 30990 points

    Hello Ashvin, 

    I assigned this to Amod, he can help further.

    COUT selection are well documented in the datasheet on section below. Please follow those recommendations as possible:  

    On Webench, once the VIN, VOUT, IOUT requirement are entered, the tool will provide you with the most optimum BOM with that requirements. You can edit the COUT by double clicking on the COUT component then go to custom part.  Their you can edit you entries per your requirements.   

    After that you can run simulation on the simulation tab with that requirement 

    Thanks! 

    Tahar

  • 0 in reply to Tahar Allag
    Prodigy 30 points

    Hi Tahar,

    Thanks for your quick response.

    1) Regarding COUT we have understood from datasheet however our concern is in on Decoupling capacitors which is being used for two FPGAs (XC7S50-1FGGA484C, Spartan 7) in PCBA having many

    Decoupling caps which are recommended (3.3V has Total decaps value 1175uF,  1V has 538uF, 1.8V has 117uF) so could you please suggest if can we go ahead with this Buck converter (TPS568215RNNR) or if you better solution then kindly advise us.

    2) We ran simulation on Webench by customizing COUT value (i.e 470uF) and TSS (2.7msec) value as per our requirement. we observed that in start up graph the Vout is reached upto value 0.53V, should be reach to 1V (refer the attached image simulation for 1V output), we want to know whether its having any issue, kindly suggest.

    Simillarly looking solution for 3.3V and 1.8V.

  • 0 in reply to Ashvin Patil
    TI__Mastermind 30990 points

    Hello Ashvin, 

    I think Webech SIM run out of time and could not get the device to fully start. I am surprised that 1V has issues, because for your 1V, 500uF with no CFF is good and you are within that spec 

    Did you try the SPICE model? I think that should give more realistic results.  

    Thanks! 

    Tahar 

  • 0 in reply to Tahar Allag
    Prodigy 30 points

    Hi Tahar,

    Could you please help me out to download Pspice tool, I had already requested to get download link for the same but yet I dont received. so we can try with pspice model.

  • 0 in reply to Ashvin Patil
    TI__Mastermind 30990 points

    Hello Ashvin, 

    Please request the PSPICE for TI on product folder, within few hours, they should send you an email where to download it. 

    Thanks! 

    Tahar

  • 0 in reply to Tahar Allag
    TI__Mastermind 30990 points

    Hello Ashvin, 

    I run some sims, the COUT you have will not make it with this device. 

    can you please look at these devices, they are DCAP 3

    • TPS54J061
    • TPS54JA20
    • TPS548A28

    Our Latest DCAP 4

    •  TPS543B20

    Also,

    • TPS543820
    • TPS543A26

    Please let me know, if any of these will meet your requirement so i can take a further look. 

    Thanks 

    Tahar