I'm trying to design a remote control. But during the process of design, I found that the output voltage of IC TPS40057 of the switch can just reach to less than 6V. The simplified application diagram of this IC is in the following: enter image description here I don't know why it can't reach higher value. Can anybody answer me why?

For further reference, the datasheet is at http://www.ti.com/lit/ds/symlink/tps40057.pdf.

Any answer will be highly appreciated!

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    \$\begingroup\$ "Any answer will be highly appreciated!". How will you show your appreciation? \$\endgroup\$
    – Andy aka
    Jan 10, 2017 at 9:30
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    \$\begingroup\$ You leave a lot of things unclear. Have you build this already and can you not reach 6 V or are you asking about the capabilities of this IC ? What it can do is in the datasheet, if that does not fit your needs, use a different IC. When used properly (Vin is high enough, load not too high, proper components used) this IC can reach 6 V easily. \$\endgroup\$ Jan 10, 2017 at 9:32
  • \$\begingroup\$ Ah,thank you..I have built this already but it cannot reach 6v, I saw the max output voltage of this IC is 6v in the datasheet, so I'm just wondering why it cannot reach... \$\endgroup\$
    – user135403
    Jan 10, 2017 at 9:55
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    \$\begingroup\$ If you want us to check, why your design can't reach your desired voltage, you have to supply more information. I.e. the values of all components used. Best thing is, you draw a new schematic with all values given. \$\endgroup\$
    – Ariser
    Jan 10, 2017 at 10:03
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    \$\begingroup\$ I saw the max output voltage of this IC is 6v in the datasheet Then you misunderstood the datasheet, it says that the maximum voltage on VFB, SS/SD, SYNC is 6V. There is no maximum output voltage specified. \$\endgroup\$ Jan 10, 2017 at 10:16

1 Answer 1


Only COMP, RT, SS/SD pins are limited to 6 volts (as stated in the absolute maximum ratings table in the data sheet). There is no reason why the output voltage from this buck regulator can't be any value that is within the range 0.7 volts to 35 volts (see link supplied by SteveG).

  • \$\begingroup\$ Thanks for your answer, maybe I had some misunderstanding before, since I'm really new to this field.. I think I should read more related materials to figure this out. \$\endgroup\$
    – user135403
    Jan 10, 2017 at 9:51
  • \$\begingroup\$ @Lumersfly any reason why you're using the TPS40057? It is an old part, TI already state "not suitable for new designs", there are much better and simpler parts available. \$\endgroup\$
    – Steve G
    Jan 10, 2017 at 9:53
  • \$\begingroup\$ @Lumersfly This gives Vout(max) as 35V. \$\endgroup\$
    – Steve G
    Jan 10, 2017 at 9:54
  • \$\begingroup\$ @SteveG thanks for uncovering the specific upper limit. I shall adjust my answer. \$\endgroup\$
    – Andy aka
    Jan 10, 2017 at 10:11
  • \$\begingroup\$ So do you have any other recommendations of this kind of IC, apart from TPS40057. Because I am new to this kind of design,so I just choose one in kynix.com/Search/TPS40057.html \$\endgroup\$
    – user135403
    Jan 11, 2017 at 4:03

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