I'm using Solar-powered projects ( including batteries ), for remote sensing/ reporting. When Battery drains below a certain voltage (~ 2.7-3.0v) due to lack of sun, MCU gets into "zombie" mode, which will not bootup correctly even if power in battery will suffice.

So, I'm looking for a cut-off circuit ( let say below 2.7v).

Can the MCP1700-3302E will do it ? Most Solar Projects shared on-line, don't take this problem into considerationSolar Project.

For those who think that choosing a better / bigger battery will solve it, you are right, this is one way, but I think that when a device comes down... must have the ability to wake up ( and notify a re-boot, or battery deficiency ).



1 Answer 1


You can try voltage supervisor like the TPS3839K33DBZR. It has a threshold or 2.93V. so when the voltage drops to 2.93V it will set the MCU into reset and keep it there untill the voltage rises to 3.3V. You can find adjustable voltage supervisor as well, open collector or push- pull configuration.

  • \$\begingroup\$ Can you please tell if the component I asked about, has a cut off ? \$\endgroup\$
    – guyd
    Jun 15, 2020 at 7:19
  • \$\begingroup\$ Just looked at the data sheet, and I want to be sure. I'm thinking through a battery voltage changeq drainage : from input of 0.6- 2.93v , this chip pulls down MCU's reset pin to GND, and from 2.94v-3.3v ? and from 3.3-6.0v ? does It supplies a 3.3v output ? \$\endgroup\$
    – guyd
    Jun 15, 2020 at 7:55
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    \$\begingroup\$ Yes that's exactly what it does. The RESET pin is what VDD is \$\endgroup\$ Jun 15, 2020 at 15:16
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    \$\begingroup\$ You can use an LDO with an enable pin and connect the voltage supervisor RESET pin to the enable pin of the LDO. Then once the voltage falls below the threshold it will shut off the LDO and cut off power to your MCU. If you have a schematic that will help. \$\endgroup\$ Jun 15, 2020 at 15:20
  • \$\begingroup\$ now I see. It is an additional component alongside the LDO \$\endgroup\$
    – guyd
    Jun 15, 2020 at 15:50

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