Hello,
We are currently using two LTC3103 to power some circuitry on our board and to power an external component. Our goal is to keep power consumption in the uA range since batteries will be supplying power to the two LTC3103 in the event that main power is cut off. We are noticing some weird behaviors with one of the LTC3103 when there is no load connected to it.
Our current setup looks as such:
We have set LTC3103 #1 to 3.3V and LTC3103 #2 to 1.5V. The two regulators take input power from the same source. At power on, we noticed that LTC3103 #2 starts ramping up slowly to 3.3V. At first, we suspected an issue with the diode and that it was improperly selected, however, we meet all of the specs to make sure reverse leakage isn't occurring and that we are well under the reverse voltage breakdown. We did a quick experiment by adding a 100K resistor from the output of LTC3103 #2 (after the diode) to ground to mimic a 15 uA load. LTC3103 #2 worked fine as intended and, after being left on a whole day, did not ramp up at all.
So, I am suspecting that the system needs to have a minimum load for the regulator to work as intended. Is this case? I thought this part would work without any load? Any insight on this would be greatly appreciated.
More Info:
MODE is set HIGH
RUN is always set HIGH (connected to input power)
VCC is connected to a 1uF cap.
FB Network:
Rtop = 1.5M, Rbot = 1M, and C_ff = 150 pF
