RX Power consumption above datasheet specs

LPWAN Modules / EVBs RAK3172
1

Hello RAK Team,

I’m trying to configure the RAK3172 in “Class C” mode and have it running at the lowest power consumption possible.

At the moment I have the module by itself, only with 10uF and 0.1uF caps connected to VDD. I upgraded to the latest FW (AT+VER=3.4.2-rui3_22q1_update.112) and I run the following commands using an FTDI adapter to configure the module and join the network:

RAKwireless RAK3172-E Example
------------------------------------------------------
Current Work Mode: LoRaWAN.

AT+VER=?
AT+VER=3.4.2-rui3_22q1_update.112
OK

AT+DEVEUI=xxxxx
OK

AT+APPKEY=xxxxx
OK

AT+CLASS=C
OK

AT+BAND=6
OK

AT+CHE=6
OK

AT+NJM=1
OK

AT+CFM=0
OK

AT+TXP=0
OK

AT+DR=2
OK

AT+ADR=1
OK

AT+JOIN=1:0:255:0
OK
+EVT:JOINED

AT+SLEEP=1000000
OK

The image attached shows the power profile, and you can see, that after joining the IDLE consumption is around 8.18mA. I disconnected the FTDI at the end to make sure there is no current leak.

image
image1508×572 63.9 KB

The datasheet specifies an RX consumption of 5.22mA, but it’s far from it.

If I run the unit as Class A, the unit goes down to 1.5uA after AT+SLEEP, which is great. Am I missing anything to get down to 5.22mA in Class C?

Thanks and Regards,
Mike

2

Hi Mike,

Class B and C operates differently than Class A. I will assume that this is under the LoRaWAN stack. But I will still share this concern to the team :+1:

3

Thansk @carlrowan.

My understanding is that Class C is continually in RX mode, so that is why I’m assuming the power consumption should be down to 5.22mA as per the datasheet when the module is IDLE after joining.

Please keep me posted about that as the power consumption figures will make our project feasible or not.

Regards,
Mike