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I have noticed multiple issues with this schematic.
1. The TAB pin is for heat-sink, and the voltage divider should be connected through ADJ/ and OUT.
2.The output voltage is not right, and please refer to 9.1.1 to use the equation there to reselect the output capacitors.
3. The TLV1117 requires >0.2Ohms ESR from the output capacitor and if C53 is a ceramic capacitor, please make sure that the ESR is meeting this requirement, and if not, please consider adding a series resistor to increase the ESR.
4. When charging a 4.4F capacitor, the LDO may enter the current limit or cycling in and out from the thermal shutdown due to the big in-rush current.
--The TLV1117 has fixed 5.0 output, and you don't need ADJ pin and resistor divider if you pick the fixed version.
2. the circuit intention is to provide 4V at the supercap node. is the output voltage of the device producing 5V?
i think the voltage drop from the diode and small resistor drops the 5V down to 4V. would you agree?
-The diode will create an additional voltage drop, but the diode drop could move with temperature and may have a large part-to-part variation. Unless you don't care about the accuracy of the output, otherwise I would not recommend using reply on the diode to achieve a certain voltage.
3. is there another device that you would recommend instead of this TLV1117? possibly a soft start feature to avoid the inrush issue?
Yes, you would definitely need an LDO that has a built-in soft-start. For your application, you have a 12V Vin, and the LDO is outputting a 5V. Do you have any other requirements for the recommeendation?
