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LM1084: R1 Resistor

TI-CSC
Genius 9610 points
Part Number: LM1084

Hello E2E Experts,

Good day.

 In the datasheet, I will be referencing sections 7.4.1 and Figure 14.

In the datasheet section 7.4.1, it suggests using a resistor of low value (around 100Ω), but I have tried using higher values to create the feedback loop for Vref and it doesn't work. I would like to know the highest values for R1 that will work, in order to reduce the overall current flow on the device.

Specifically, I need to know the highest value that R1 can be.

Seems the resistor values are far too high. This doesn't work. The math is all right, but I realized today that section 7.4.1 wants something lower.

The problem with lower values, as you may see already, is that it can lead to a lot of current drains.

Again, all I need to know is the highest value R1 can be to create the 1.25V ref voltage. The values I have now do not work and I am referencing 7.4.1.

I need 3.3V, 4.1V, and 5V with three separate LM1084s.

Regards,

CSC

  • 0
    TI__Mastermind 38195 points

    Hi CSC,

    Section 7.4.1 explains clearly why the resistor values must be small - IADJ is large for this device. If you want lower current consumption for biasing you need to use a newer device that has lower leakage. Is there any reason you have chosen to use this device specifically?

    Regards,

    Nick