I´m trying to calculate my LD1086PUR to output 5v and 3.3V for an ESP32 and somehow can´t get it right. Does someone have an idea which resistor I should use or how I can calculate the resistor? I tried the Vo=Vref * (1+R2/R1) but it doesn't seem to add up.
Welcome, @MOssw.1, to the community!
The LD1086 is a quasi LDO that can derive exactly an output voltage from an input voltage. If you want to generate two voltages with a single LD1086, i.e. 5V and 3.3V at the same time, this will therefore not work.
Otherwise the formula Vo=Vref*(1+R2/R1) is correct and fits perfectly - if you use the reference voltage (mentioned in the data sheet) and the given resistance. Right next to the formula, the resistor R1 is already specified as 120 ohms, so that its current is large enough not to disturb the Adjust Pin Current IADJ (see datasheet, table 8). Of course you also have to change the formula to R2, but that shouldn't be a problem, should it?
Good luck!
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/Peter
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