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Part Number: TPS54560-Q1
Other Parts Discussed in Thread: TPS54560B, , LM61495-Q1, LM61440-Q1, LM61460-Q1, LM61440, LM61460, TPS54560, TPS54560B-Q1

Dear Support Team,

my company has succesfully used the TPS54560B IC in the design attached for a 12V to 5V conversion.

Due to recent shortages we had to choose an alternative part. We have the TPS54560-Q1 which seems to be compatible.

From what we've seen testing the two parts on webench, there should be no big differences in the converter's surrounding circuitry.

We tried a one to one substitution on our board, but it did not work. The system using the TPS54560-Q1 becomes unstable when the load current increases, and when it reaches values above 2.5A, Vout falls up to 4V or less.

Can you please suggest any solution for the new part to perform correctly?



  • Hi Antonella,

    What is your maximum input voltage and load current requirement?

    If the input voltage can stay within 36V, then I would suggest looking at LM61440-Q1 (4A) device which should satisfy your application design requirement for 12Vin|5Vout application. Alternatively we have LM61460-Q1(6A) in the same device family or the most recent released device LM61495-Q1 (10A).

    Note only LM61440 and LM61460 are pin-to-pin compatible as detailed in the front page of the datasheet.



  • Hi Jimmy ,

    thank you for your reply. 

    Our input voltage may vary between 11V and 16V. We hope to make available up to 5A for the load, but any improvement to the present max2A would be appreciated.

    Sholud we change the switcher on our board, we would prefer a part with the same package as the TPS54560. Unfortunately the LM614XX have a different package.

    I can't understand the problem with this circuit, as it is very similar to what webench suggest for both the TPS54560B and the TPS54560-Q1, but only the former works well (we do actually reach 5A output current while the output voltage remains close to 5V).

    May you suggest a different choice on the component values?

    Or may you suggest where to find the TPS54560B on stock?


  • Hi Antonella,

    Thanks for the clarification here. 

    When testing can you make sure that your input power supply is not current limited. 

    The TPS54560B should not be different to the TPS54560-Q1 other than the later being automotive qualified. 

    However since the later is not recommended for new designs, TI recommends switching to the TPS54560B-Q1 device for future designs.

    Can you confirm that your previous design using the TPS54560-Q1 works as expected and the newly swapped TPS54560B device on the exact same board is having this issue?

    If it is, I'd suggest trying another new unit from your tape-and-reel and retest. I wonder if it is a device issue which may be caused by improper reflow/ assembly.



  • Hi Jimmy,

    thanks for your suggestions. 

    In this case, input current should not be the issue, also we tested the board mounting the TPS54560B, an then the TPS54560-Q1, under the same conditions.

    Can you confirm that your previous design using the TPS54560-Q1 works as expected and the newly swapped TPS54560B device on the exact same board is having this issue?
    Note: in fact, the contrary is true. The board was designed for the use of TPS54560B in the first place, then because of supplying issues we need to momentarily arrange another solution.

    We hoped to make the TPS54560-Q1 (or any other alternative part) work.Two units of TPS54560-Q1 have been tested, they behave the same. Plus, the layout gives planty of space to the pad (GND) connection for heat dissipation.

    Any other idea on how to improve the TPS54560-Q1 circuit performances?

    Thanks again



  • Hi Antonella,

    I run the schematic through the calculator and it looks ok.

     3823.Copy of TPS54360-361FAMILY_CALC_TOOL_REVE.xls

    Do you have the waveform of the SW node, VIN, VOUT at 2A and at 4A with the TPS54560-Q1?
    Also, do you have the layout of your design?

    Alternatively you can try using the TPS54560B-Q1

    The difference between B and non-B version is listed here