Current consumption issue of nRF21540 when using antenna 2

[Noah_iR]

Hello. 

There was a problem with high current consumption when using Antenna 2 in some products.

The failure rate seems to be less than 7%, and the current consumption increases by about 100uA.

Main MCU is nrf5340 and NCS version is v2.5.0

According to 3.4.[13] System: Increased supply current in Powerdown state with digital input pins at high level of "nRF21540_Revision_2_Errata_v1.2", the ANT_SEL pin should be held low in Power-down state. However, when we measured it, it seems to be held high, which may be causing the high current.

Since all pins that are mentioned on that errata report are handled by NCS library, I can't control that ANT_SEL pin.

I looked at the release notes for the other NCS versions and it doesn't seem like there was a fix for this.

Is there a NCS version that has a workaround for this?

[Kazi Afroza Sultana]

Hello,

There is a previous case about controlling ANT_SEL pin https://devzone.nordicsemi.com/f/nordic-q-a/91220/ncs-and-nrf21540-with-custom-protocol?ReplyFilter=Answers&ReplySortBy=Answers&ReplySortOrder=Descending;, you can look at. It may help.

BR
Kazi 

[Noah_iR]

It seems a little different from my case.

We are using BLE and all control of nrf21540 is handled by mpsl/fem of NCS.

The  our application does not separately handle sleep/wake up, but NCS controls it according to the set advertising interval. In other words, the user does not do anything separately.

Every thing works well except for the current consumption on some units. 

I assigned pins for nrf21540 fem like : 

    nrf_radio_fem: nrf21540_fem {

        compatible = "nordic,nrf21540-fem";

        tx-en-gpios = <&gpio1 13 GPIO_ACTIVE_HIGH>;

        rx-en-gpios = <&gpio0 30 GPIO_ACTIVE_HIGH>;

        pdn-gpios = <&gpio1 10 GPIO_ACTIVE_HIGH>;

        ant-sel-gpios = <&gpio0 2 GPIO_ACTIVE_LOW>;

        mode-gpios = <&gpio1 11 GPIO_ACTIVE_HIGH>;

        supply-voltage-mv = <3300>;

        spi-if = <&nrf_radio_fem_spi>;

    };

 

and here is my confing setting for FEM

# for FEM temperature compensation

CONFIG_SPI=y

CONFIG_SENSOR=y

CONFIG_TEMP_NRF5=y

# BLE tx power

CONFIG_BT_CTLR_TX_PWR_ANTENNA=10

CONFIG_MPSL_FEM_NRF21540_GPIO_SPI=y

CONFIG_MPSL_FEM_BUILTIN_POWER_MODEL_UPDATE_PERIOD=3600000

CONFIG_MPSL_FEM_NRF21540_RUNTIME_PA_GAIN_CONTROL=y

 

If you set it like this, NCS will automatically control FEM for each advertising cycle set in appcore.

I think ANT_SEL should also be controlled by NCS according to Workaround, but it seems to always have a fixed value.

[Kazi Afroza Sultana]

Hello,

There is a workaround here https://docs.nordicsemi.com/bundle/errata_nRF21540_Rev2/page/ERR/nRF21540/Rev2/latest/anomaly_540_13.html. I need to check if it is implemented in the mpsl driver.

You can check the trace codes for the devices (7%) with higher current draw, if these are earlier than stated in these errata then you should expect higher current draw for these devices:

https://docs.nordicsemi.com/bundle/errata_nRF21540_Rev2/page/ERR/nRF21540/Rev2/latest/anomaly_540_14.html