IIS3DWB uses ~275uA in Low power mode - not 5uA-16uA

[KMeld.1]

I have an issue with current consumption of a IIS3DWB using the STEVAL-MKI208V1 kit.

I have previously discussed it in this issue, but I've traced (i hope) the issue to the VDDIO pin.

I'm using a STM32WB55CEU6 as SPI master.

To measure current I'm using the X-Nucleo-LPM01A.

When the ISS3DWB is in low-power mode it should use 5-16uA, but I'm measuring ~265uA.

Schematic:

 

Measurement of ONLY the STEVAL-kit VDD-pin (ISS3DWB in Low-power - VDDIO pin connected to MCU VDD):

 

Measurement of the STEVAL-kit VDDIO-pin (ISS3DWB in Low-power - VDD pin connected to MCU VDD):

Measurement of STEVAL-kit VDD + VDDIO in low-power-mode

 

I'm not sure I understand why VDDIO is drawing so much current - isn't it supposed to be the SPI voltage reference?

Any ideas?

Regards

[Eleon BORLINI]

Hi @KMeld.1​ ,

which Vdd level are you using?

Please consider that a general suggestion is to keep the VddIO level equal or below the Vdd level.

And note that the VddIO will draw the current generated by the commutation of the dataout drivers during SPI communication.

-Eleon

[KMeld.1]

Hi @Eleon BORLINI​ 

Vdd is 3.3V across the whole system. VddIO is connected to this *** well. Only for the "pure" VddIO meassurement was it isolated on the X-Nucleo-LPM01A meassurement pin.

I can see now that one grapch wasn't included in the original post - please see edit.

i can definately tolerate current consumption of the SPI suring communication and sampling, but what bothers me is the current draw AFTER I put the IIS3 into "low-power-mode" and deinit the SPI on MC (2nd graph).

Couldi t be releated to the 33Ohm resisters on the STEVAL-kit?

regards.

[nandhinis]

We have set the register "write [000] to XL_EN[2:0} in CTRL1_XL(0x10)" and SPI(MOSI,MISO,CLK),INT1,INT2 are low voltage at sleep mode but still the current consumption is 0.28mA.Please let us know the exact pin configurations(Pull,Mode,Value) to be done at MCU(STM32L562) in sleep mode.

[nandhinis]

Hi ,

We have configured SPI pins and No SPI communication in sleep mode .VDD and VDD_IO are in same voltage(3.3V) and all SPI pins Low voltage and INT also low except NSS pin. Still current consumption is 0.28mA. How can we get the current consumption in power down mode as per vibration sensor(IIS3DWBTR) datasheet.