Can the LT1389 work reliably below 0C? The datasheet says a low end operating temperature range of 0C but a few of the test figures show data at -40C.
LT1389 may not be damaged when operated below 0C but data-sheet specification cannot be guaranteed. Given that LT1389 is low power, it may not always cleanly start at cold. I recommend checking startup (toggle power a number of times) of LT1389 at low temperature.