I'm using a voltage detector for a solar powered ESP8266 project. Its purpose is to make sure that if for some reason the battery goes below a certain value (around 2.7v) then the MCU goes into "zombie" mode and does not power up as needed again. So I tried to use a voltage detector.
According the datasheet (see
Test 5 figure)- there is a resistor
RL which noted at the beginning as 200 ohm, and a capacitor, whose value is not noted anywhere.
When using without
RL and capacitor, erratic behavior after sleep reboot occurs causing it to it to fail (MCU's led flickers very rapidly.)
Is there a rule of thumb for the capacitor?
Although tried several combinations of R1(200,1K, 10K) and C1(3.3 to 1000uF), I still get the following behaviour :
Dropping down input voltage from 5.5v to 3.3v works as expected (ON ), while going below 3.3v - cutting off the voltage to merely 0.1v ( measure at RST ).
Going back up ( 0v -- ~2.5v ) - measures 0.1v anf then, until ~3.8v (!!) MCU's boot led flickers, while measures at RST pin rises from 1.6v at some point to 3.0v ... and when Vin reaches 3.8v RST pin is arround 3.3v.
when MCU is not connected, going up & going down behaves as expected.