Hello,
I measured the current consumption of a specific iot device i designed (just composed by uC+sensor+passive components) quantity is around 500 pieces. i plot the current consumption in sleep mode in google sheet but i found that the distribution is so big some devices consume under 10uA but also there are other which consume more than 20uA which in some cases more than 3 times. (picture attached)
I didn't understand the reason behind this wide range.
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Check if you have any uC or digital I/O pins configured as inputs, which are floating. If they are unused bi-directional, try configuring them as active outputs. Floating I/O pins will increase the current draw; the excess current will vary from one device to the next.
I've seen a related problem in a low-power application, that used a telephone line as a power source for a uC-based circuit. The operating current budget was 70 uA max under worst-case conditions. Our prototype software failed to initialize unused I/O pins to outputs, resulting in excessive quiescent current. The extra, unwanted, 20 uA current draw threatened the whole project. The solution was to initialize the uC carefully, immediately after power-up.