lsm303agr power-down current consumption?

[CSharpino]

I have several lsm303agr that with the accelerometer and the magnetometer in power-down mode consume between 40uA and 20uA while others consume about 2uA as indicated on the datasheet.

Even if they have this higher consumption, they perform the self tests correctly.

What could this behavior be caused by?

In my board Vdd = VddIO = 3V

[Federica Bossi]

Hi @CSharpino​,

As specified in the datasheet the typical value of 2uA is measured when Vdd=2.5V and with a temperature of 25 °C.

Can you retest the parts that consume 40uA or 20uA under these conditions and let me know if this extra consume is already present?

Thanks

[CSharpino]

I tried with a 2.5V supply voltage, consumption drops but always remains between 30uA and 15uA.

[Federica Bossi]

Ok, can you share your board's schematic?

[CSharpino]

This is the schematic. Don't pay attention to the fact that IIS2MDC is written there because the board provides the possibility to mount this component too.

The power is supplied through the Mosfet Q4 to have the possibility to completely switch off the component when not in use.

To put the device into power-down mode using these calls to the ST driver:

	lsm303agr_mag_operating_mode_set(&mag_ctx, LSM303AGR_POWER_DOWN);
	lsm303agr_mag_power_mode_set(&mag_ctx, LSM303AGR_LOW_POWER);
	lsm303agr_xl_data_rate_set(&xl_ctx, LSM303AGR_XL_POWER_DOWN);

[Federica Bossi]

Hi @CSharpino​ ,

The schematic seems ok, what you could try is to reverse commands like this:

• lsm303agr_xl_data_rate_set(&xl_ctx, LSM303AGR_XL_POWER_DOWN);
• lsm303agr_mag_power_mode_set(&mag_ctx, LSM303AGR_LOW_POWER);
• lsm303agr_mag_operating_mode_set(&mag_ctx, LSM303AGR_POWER_DOWN);

Let me know if this helps.