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TPS548B27: Regulator part suggestion

Shifali N
Expert 2145 points
Part Number: TPS548B27
Other Parts Discussed in Thread: TPS53355, TPS548B28, LM27402

Hi,

I am looking for a Buck Regulator with below requirement also which can support transient of 25A to 30A

Vin=3.3V, Vout= 0.8V, Iout=20A to 25A

Can you please suggest a regulator which can handle higher transients.

Minimum Vin requirement is 3V. What is maximum transient that TPS548B27 can handle.

  • 0
    TI__Mastermind 23695 points

    The TPS548B27 current limit will limit the output current to ~25A or less, so I do not think it will be a good fit.      

    The TPS53355 supports 30A and has a split rail input (power stage input and the device bias) 

    The 3.3V input  can connect to the power stage input (VIN pin) and use a small charge pump or boost converter to supply the VDD pin.

    The charge pump/boost should convert the input of 3.3V to 5V or greater on VDD.  

  • 0 in reply to David_Daniels
    Expert 2145 points

    Hi David,

    My total power consumption of the SoC is around 13A. So I am planning to use TPS548B28 which has a capability to support 20A.

    1. What is the maximum transient TPS548B28 can support.

    2. I am not planning to use TPS53355 as it will be way beyond my current requirement. Whether TPS548B28  is a right selection?

    3. Whether VCC and VIN of TPS548B28 can be connected to same same supply voltage of 3.3V?

    4. Is there any other better suggestion?

  • 0 in reply to Shifali N
    TI__Mastermind 23695 points

    What is the transient specification? 

    The TPS548B28 uses the DCAP3 control and has fast transient response. 

    I do not know your size and cost constraints, so to state max transient can be misleading.   

    I have seen applications that load step rate as high as 15A to 20A/us, but the voltage level was 1.0V

    There are pspice and simplis models on the product folder that can be used the assess the transient response.

    Additionally, the webench tool is available on the product folder.   Webench can be used to calculate a design and simulate the transient. 

    If the peak currents are 25A, then TPS548B28 is probably not a fit

    3. Whether VCC and VIN of TPS548B28 can be connected to same same supply voltage of 3.3V?  Yes

    I have seen LM27402 used for the 3.3V input applications it use a voltage mode control, but I believe the TPS548B28 will have better transient. response. 

  • 0 in reply to David_Daniels
    Expert 2145 points

    Hi Daniel,

    If my transient response is somewhere around 16A to 17A will the regulator be able to support?

  • 0 in reply to Shifali N
    TI__Mastermind 23695 points

    yes, use the design to determine the components and the simulations tools to verify. 

  • 0
    Expert 2145 points

    Hi David,

    May I know what is the difference between TPS548B28 and TPS548B27?

  • 0 in reply to Shifali N
    TI__Mastermind 23695 points

    The TPS548B27 is a different package.   The 'B27 has 0.5mm pin pitch.   The 'B28 has a 0.4 mm pin pitch