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TPS7A24: Question about LDOs

Part Number: TPS7A24

Hello,

I have a question regarding LDO regulators.  What is the difference between quiescent current (Iq) and ground current (Ignd).

Based on the graphs in figures 9 and 10 below (for the TPS7A27), they are very different.  However, in TI’s document SLVA079 (also shown below), it is implied that they are the same thing.  I have found other documentation that also say this.  So, what is ground current and which specification should I be focused on for low power battery operated devices?

 

Thanks!

Connor

  • Hi Connor,

    These terms are often used interchangeably, but the actual difference is that Iq is Ignd at zero load. This is why in the figures the load for the Iq plot is zero while the load for the Ignd plot is 1mA (non-zero). Many of our newer parts have dynamic biasing circuits which change the biasing depending on the available supply, so Iq is used as a sort of minimum biasing. 

    Regards,

    Nick