L86 EVB power supply requirements


I’m trying to measure the power draw of the L86 module on the L86EVB board by powering it using an external 3.3V supply. I have opened switch S101 and am powering from the J302 jumpers successfully with an external 3.3V supply.

When I first power on the unit in this configuration I have found that it draws >500mA which is far in excess of the 100mA listed on the L86 datasheet. Is this an error in my configuration or is the datasheet incorrect? I am trying to power the device using an STLINK-V3PWR but it is tripping on current overload.


HI Brad
Can you take a picture of the module and describe how you tested it? Are there other modules besides the L86 module on the test board?

Hi George,

Thankyou for responding, in terms of testing I’ve just isolated the L86EVB and I’m attempting to power it straight off the STLINK-V3PWR debugger but even in this configuration the debugger trips on over-current from the inrush.

The full circuit would include additional MCU and circuitry but at the moment I’m just doing early development


Hi Brad
Please use the standard USB interface as shown in the picture to test again. The current consumption should not be that high.

Hi George,

I appreciate the response although this doesn’t help me measure consumption when powered by a 3.3V supply.

I’m looking at deploying these in an IoT application and it is power restrictive so I’m trying to get an accurate idea of the consumption under different scenarios. It looks like the development board might be adding additional current draw though. I’m leaning towards creating custom hardware for this testing instead of trying to do it on the board but I’d appreciate if there’s anything I can change in my setup.