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Q: FW: LDO TPS74701 V-Dropout by 245714
HiThere seems to be a discrepancy in the datasheet, or perhaps I'm not interpreting it correctly.
Figure 8. shows that the Vdo at about (Vbias-Vout of 1.6V) is less than 60mV, but Vdo is listed as 120mV in the Electrical Characteristics Table. Why the discrepancy?
A: Re: FW: LDO TPS74701 V-Dropout by 10449
You are correct that the typical Vbias dropout in the electrical specifications table is 50mV and the maximum is 120mV. The Vbias dropout in figure 7 very closely matches the typical value. These table and the graph can be different because these are only typical values and are calculated differently for display in the datasheet. The table probably shows the maximum measured dropout voltage of 50mV and the graph shows the average dropout voltage of 40mV. The maximum dropout voltage of 120mV in the table is the worst case specified dropout voltage. If you need a worst case design, you should use the 120mV number. You can then scale the 120mV number based on temperature, Vbias-Vin, or load current per the graphs in the datasheet. Also be sure to refer to the application note Understanding LDO Dropout http://focus.ti.com/lit/an/slva207/slva207.pdf
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