Current consumption difference nRF51422 and nRF51822

[Bart de Kramer]

I'm had develloped some software and tested it on the nRF51-DK. After that I made my own PCB design where only the nRF51422 is replaced by a nRF51822. When I flash both with exactly the same software, the nRF51-DK consumes about 5.6uA and my own PCB about 2350uA. Is there a difference between the nRF51422 and nRF51822 which can cause this big difference?

I'm using softdevice s110_nrf51_8.0.0.

[Bart de Kramer]

Hi Hung, First of all, happy newyear! Tomorrow I started again with the problem above. As you suggested I changed the values for L1 and C5 as showed in the nRF51822 PS (L1 = 10nF, C5 = 2.2pF) and removed the SWDCLK pulldown. But I still have that high current consumption.

The tests you suggested gives the following result: Erase SoftDevice:

1. 4.26 mA current consumption
2. 9.4 uA current consumption

Flash softdevice:

1. 2.07 mA during idle and a peak of 2.65 mA every 500msec (I assume this is because of the advertising). But if I scan for bluetooth devices with my phone I also cannot find the unit.

[Hung Bui]

Hi Bart,

Thank you, and Happy New Year to you too.

The 2 test cases without softdevice showed the expected result => no issue with the chip or other peripheral on board. The test with softdevice showing 2mA during idle is pretty strange, have you made sure you power reset the chip after flashing ?

The chip will enter debug mode after flashing and can consume more power. ( it should be around 30uA average current consumption with 2-3 uA when in sleep mode - idle)

You can test if the radio cause the exceed power by removing the advertising_start() function, so that there is no RF activity but with the softdevice active.

Note that you should test with SDK v6.x (and S110 v7.0), SDK v7 and above were not tested with Revision 2 chip (only revision 3).

[Bart de Kramer]

Hi Hung, The debug mode is not the issue. I send the command <nrfjprog --pinreset> after each flash cycle. But, I'm using Softdevice S110 V8.0.0! I'm not sure which SDK I'm using. Do you know where I can check the SDK version (I'm using Keil 5).

[Bart de Kramer]

I've tried SoftDevice S110 V7.1.0 but I still get that high current. As soon as I call SOFTDEVICE_HANDLER_INIT(NRF_CLOCK_LFCLKSRC_RC_250_PPM_TEMP_4000MS_CALIBRATION, NULL); that high current occurs

[Bart de Kramer]

Hung,

I've tried some other things. I've created an simple program what just initialize the clocks (LF and HF). When I only start the LF clock, I get a current draw of 10uA. Otherwise, if I also try to start the HF clock and then wait untill it is started (: while (! NRF_CLOCK->EVENTS_HFCLKSTARTED) {}) I never pass this while loop and the current consumption stays at 2mA! It looks like the HF clock won't start