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TPS76901-HT: TPS76901-HT dropout voltage

Part Number: TPS76901-HT
Other Parts Discussed in Thread: TPS76901-EP, , TPS7H1201-HT

Hi,

The datasheet for both the TPS76901-HT and TPS76901-EP says -

To calculate the minimum input voltage for your maximum output current, use the following formula:

  Vi(min)=Vo(max) + Vdo(max load)

However Vdo isn't given. The features section says it's typically 71mV at 100mA but I expect this sort of information to be given in the Electrical Characteristics or even a graph of Vdo against load.

Is such a graph available?

Mike

  • Hi Michael,

    Unfortunately I do not think we have such a graph specifically for the -HT or -EP version. I would recommend that you stay within the recommended input and output voltages (5-10Vin and 1.2-4.5Vout) and you should be good across the range of 10uA to 100mA (see the first line of the electrical characteristics table).

    The commercial version of this part (which is likely very similar to the -EP or -HT version) does has a graph of typical Vdo across temperature and at 10mA and 100mA. This may be useful for you. It's figure 10 at www.ti.com/.../tps769.pdf

    Thanks,
    Kyle
  • Unfortunately I need to generate a few mA at 3V from a 3.3V rail so that is outside the recommended operating range for this part.

    Out of interest, if the minimum input voltage is 5V and the maximum output voltage is 4.5V how can the datasheet say the typical dropout voltage is 71mV? To get that you must be operating outside the recommended range.

    Mike

  • Hi Michael,

    If the minimum input voltage is 5V and the output is 4.5V the dropout would be 500mV which is greater than the typical 71mV. Let me discuss with my team if we support your required input and output voltages. If not I will see if we have another part to recommend. What temperature range did you need this part to be rated for?

    Thanks,
    Kyle
  • Hi Kyle,

    I need to operate at 125C so a junction temperature of 150C.

    Mike
  • Hello Mike,

    Sorry for the delay. Since our recommended operating range has 5V as the minimum input I have determined this IC will not work for your needs. The formula you initially mentioned is for use withing the operating range.

    I would suggest looking at the TPS7H1201-HT for your use.

    Thanks,
    Kyle