Power consumption for nRF24LU1

[Jeffery]

Hi Did you have tested the power current of nRF24LU1 when RF was off and USB worked normally?
We want it less than 4mA. Could you have any idea to make it? Thanks.

[Håkon Alseth]

Hi Jeffery,

The typical current draw of the USB (including PLL etc.) when active is 4.4 mA. If you are then also running the MCU at 16M, then the total current consumption will be: 6.3 mA (16M speed) + 4.4 = 10.7 mA.

The best case scenario is to lower the MCU clock speed, which then will be similar to: 1 mA (32 kHz MCU speed) + 4.4 mA = 5.4 mA

There is a power-down option in the LU1+ (PWRDWN register), where you can set wakeup-on-USB (or RTC/pin/RF), which consumes 480 uA (Istandby). The wake up time from this mode is specified in the electrical specification, which is chapter 5 in the datasheet.

Best regards Håkon

[Jeffery]

Dear Hakon Thanks for your reply. How about nRF24LU1+OTP? I checked the datasheet. Its USB active current is 3mA. Assume RF is off and USB is active (not suspend). The power current is as below?

1 mA (32 kHz MCU speed) + 3.0 mA = 4.0mA

[Håkon Alseth]

Hi Jeffery,

The USB current is lower, but the MCU current is higher in the OTP part. This has to do with the physical properties of OTP memory.

The lowest number is then: 3.5 mA (MCU) + 3 mA (USB) = 6.5 mA

Best regards Håkon