nickelflippr
Member
that ON Semi part is a nice one, could be on the low side to power an SD card?The typical quiescent currents were 400uA (Texas TPS73133), 170uA (Texas TPS79133) and 1.1uA (ON Semi MC78LC00).
So with a 1000mAh battery, at 0.4mA or 0.17mA you aren't going to get a full year from the LDO alone even if the PIC is in sleep mode. But from the 1.1uA you are going to get more years than I will probably be alive!
I'll try and use sensors that don't require the internal ADC or a highly accurate Vdd/Vref, that could work nicely with a single diode drop. But given the calculations above, is an LDO really the spawn of the devil?
A fully charged LiCo battery is 4.2V, so choose the diode carefully if you go that route. For instance, a small signal diode at a couple of ma's will only be approx. 0.4V.
A TL431 voltage reference, and or resistor/divider networks can be sourced from a micro I/O pin when awake.