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LP2986: LP2986 Programmable Vout ratings enquiry

Part Number: LP2986


i'm looking for a wide Vin low noise LDO which is able to take in 9V+ Vin & i've found the LP29856, unhowever on my Vout i'll need to get 8.4V/200mA. Is possible for me to get this outing ratings even it's exceeding 5V Vout?

As i read through the programmable Vout configuration, resistor divider on the output side will still be relying on regulated output. Hence if i'm using LP2985ILD-5.0/NOPB with resistive divider configuration, this mean i'm expecting to get output which are lower then 5V correct?


  • Hi Leo,

    An LDO's output voltage is set by the internal voltage reference and the feedback network which is typically a resistor divider. For the 5.0 version of the LP2986, the 5 V output is only achieved when connecting the internal resistor divider (SENSE and TAP pins) to the OUT and FEEDBACK pins as shown in Figure 29 of the datasheet. If SENSE and TAP are unconnected and OUT and FEEDBACK are connected to an external resistor divider, an output voltage of 8.4 V can be achieved as shown by the configuration in Figure 30 and Equation (1). Rearranging for R1:

    R1 = R2 * (Vout/Vref - 1) = 51.1k * (8.4/1.23 - 1) = 297.9 kOhms

    Keep in mind that an external compensation capacitor is also required and calculated with Equation (2):

    Cf = 1/(2*pi*R1*50k) = 1/(2*pi*297.9k*50k) = 10 pF