I have a question regarding optimising design for ultra low power consumption device. I'm trying to develop a remote sensor node that should measure and send data every few hours.

Currently I have an RTC (DS1337) that wakes up my MCU (ATMEGA328P) from deep sleep via hardware interrupt. While the sleep current is fairly low ( avg 76 uA), it is still a fairly large amount if I aim for a device to run in the wild for couple of years.

Could I instead, use the RTC to ENABLE/DISABLE the 3.3v LDO (MIC5404) thus shutting completely down the MCU and have the RTC runs on a separate coin cell battery? I think this is called power-gating. What will be the hidden disadvantage ?


RTC: https://datasheets.maximintegrated.com/en/ds/DS1337-DS1337C.pdf

LDO: http://ww1.microchip.com/downloads/en/DeviceDoc/MIC550x-300mA-Single-Output-LDO-in-Small-Packages-DS20006006A.pdf

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    \$\begingroup\$ We need links to the datasheets for the RTC and LDO. \$\endgroup\$ Feb 27 '19 at 17:05
  • \$\begingroup\$ Hi Elliot, I have edited the original message, adding the reference for MCU,LDO and RTC. Thank you \$\endgroup\$
    – Waz
    Feb 27 '19 at 17:11
  • \$\begingroup\$ Your ATmega probably doesn't need a regulator at all. What sort of battery are you using? \$\endgroup\$ Feb 27 '19 at 17:14
  • \$\begingroup\$ 3.6V Li-SOCL2 (LS14250) currently, but I'm looking to use coin cell 3V battery instead for form factor reduction. If there is no need for an LDO indeed, then I would do power gating via JFET instead. However my question remain, as I fail to see any disadvantages of power gating vs. wake/sleep. \$\endgroup\$
    – Waz
    Feb 27 '19 at 17:15
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    \$\begingroup\$ Please provide links to the datasheets for the RTC and LDO. Don't make us search for them. \$\endgroup\$ Feb 27 '19 at 17:15

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