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LM26001 input voltage for output voltage

Atsushi Yamauchi
Genius 4810 points
Other Parts Discussed in Thread: LM26001

I would like to confirm input voltage of LM26001.

For example, in the case of vout = 5V, how much is input voltage for vout =5V?

There is the figure for low input voltage dropout. In the figure, about 5.5 is OK for 1A, but I don't know for light load.

Could you please advise it?

Best regards,

Atsushi Yamauchi

  • 0
    TI__Genius 11085 points

    Atsushi,

    Light load should work if 5.5V is ok for 1A, since a large part of drop out voltage is the voltage drop on the HS switch. The more current the higher drop on the on time resistance.

    Figure 14 in the datasheet provides dropout voltage over temp at 1A and 40mA. The dropout voltage for 40mA is much lower than it is for 1A.

    regards,

    Yang

  • 0 in reply to YangZhang
    Genius 4810 points

    Dear Yang-san,

    Thank you for your reply.

    I have a question.

    In figure 14, there is not data of 40mA over about 5.2V. 

    In the case of over 5.2V with 40mA, is the dropout voltage lower than 1A, isn't it?

    I don't know the impact by light load condition (discontinuous operation, PFM and so on).

    Could you please reply it?

    Best regards,

    Atsushi Yamauchi

  • 0 in reply to Atsushi Yamauchi
    TI__Genius 11085 points

    In Figure 14, the dropout voltage is measured by (VIN-VOUT) when the LM26001 operates in dropout mode.

    The output condition is Vout=5V. When Vin > 5.2V at 40mA, the LM26001 regulate normally at 5V output voltage, not operating in dropout condition. That's why there's no dropout data when Vin > 5.2V.

    If the IC works properly at higher load at a certain VIN, it should work fine with lower load as well.

    Regards,

    Yang

  • 0 in reply to YangZhang
    Genius 4810 points

    Dear Yang-san,

    Thank you for your help.

    I understood it.

    Best regards,

    Atsushi Yamauchi