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Original question:

TPS54719: TPS54719RTER

TPS54719: TPS54719

Puspam Nayak
Prodigy 140 points
Part Number: TPS54719
Other Parts Discussed in Thread: TPS62870-Q1, TPSM8287A12, TPS568215

Hi,

We are planning to use TI buck converter part no. TPS54719RTER as 3.3V Output powering VCCIO of two Xilinx FPGAs Spartan-7 (XC7S50-1FGGA484C, 2 qty)

VIN = 5V

Vout = 3.3V

Iout = 2.2 A (Static load)

Total load capacitance = 1173uF (decoupling capacitors)

Could you please let us know how much inrush current will drive through the Input supply and whether it is reliable solution, possibly share waveform for the same.

  • 0
    TI__Guru*** 147950 points

    Hi,

    The TPS54719 is a very old device.  Why do you want to use it?

    We have the new TPS6287x family, which is designed to power FPGAs and processors.  You can use the TPS62870-Q1 and set Vout to 3.3V through I2C.  If this is not possible, we have the 12A TPSM8287A12 power module, which allows you to set 3.3V without I2C.  There is a 6A version of that device, which is pin to pin.

    The inrush current for any buck can be estimated by Iout = Cout * Vout / Tss + Iload.  The inrush into the output is the load current during soft start + the current required to charge the output caps.  Then, convert this output current to an input current with: Iin = Iout * Vout / (Vin * eff.)

    Thanks,

    Chris

  • 0 in reply to Chris Glaser
    Prodigy 140 points

    Hi Chris,

    Could you please let me know End of Life (EOL) of part# TPS54719.

    Also Please suggest a part without I2C pin. Because due to board space constraints we do not need any extra pins 

    Regards,

    Puspam 

  • 0 in reply to Puspam Nayak
    TI__Guru*** 147950 points

    Hi Puspam,

    TPS54719 is not EOL.  It is just old, so there are better options available.

    If you don't want the I2C, you can use the TPSM8287A12 module and not use the I2C pins.  This can support 3.3Vout through hardware connections and can drive your large output cap.

    Chris

  • 0 in reply to Chris Glaser
    Prodigy 140 points

    Hi Chris,

    Thank you for the information, was trying to check if i can see simulation results of TPSM8287A12 (3.3V, 6A) in WEBENCH tool however unable to find the model. Could you please suggest.

    Regards,

    Puspam

  • 0 in reply to Puspam Nayak
    TI__Guru*** 147950 points

    Hi Puspam,

    You can type in the part number directly into Webench here: https://www.ti.com/tool/WEBENCH-CIRCUIT-DESIGNER

    Or, you can find the direct link to that device's model here: https://www.ti.com/product/TPSM8287A12#design-tools-simulation

    There is also real, measured efficiency data in the D/S.

    Chris

  • 0 in reply to Chris Glaser
    Prodigy 140 points

    Hi Craig,

    Would like to inform that during our review we are planning to go with Buck converter Part no. TPS568215. Few queries related to this part. 

    Query 1: I have downloaded Simulation model of this part TPS568215 but unable to pull this part in tool TINA. Can you please suggest the path forward ?

    Query 2: I can find TPS568215 in WEBENCH. Wanted to know can we control the Ramp up time of VIN in WEBENCH and can we change the Load capacitor values (decaps) as per our requirements and Re-run the simulation. Wanted to confirm because finding some limitation with WEBENCH. 

    Request you to reply at earliest

    Regards,

    Puspam

  • 0 in reply to Puspam Nayak
    TI__Guru*** 147950 points

    Hi Puspam,

    Can you let me know why you want to use that device?

    Please make a new thread, using that part number, for support.  Different people support it.

    Thanks,

    Chris

  • 0 in reply to Chris Glaser
    Prodigy 140 points

    Hi Chris,

    Reason why we are not considering part# TPS62870-Q1  or TPSM8287A12 is, we have VIN = 5V  whereas upper limit VIN (max) of these Buck converter is 6V so considering derating we decided to go with TPS568215  having upper limit VIN (max) = 17V.

    As you suggested we will raise new request however if you have any other solutions then requesting your advise.

    Appreciate your support. Thank you !

    Regards,

    Puspam

  • 0 in reply to Puspam Nayak
    TI__Guru*** 147950 points

    Thank you for explaining.

    The 6V rating of those devices is sufficient for a 5V input.  That is what they are mainly used for.  You are, of course, free to get more margin if you want.

    Chris