What if I use a power supply of 3.3v for the LSM9DS1 module?

[jg_spitfire]

Hi, in the module specifications (bottom of page 12 of the datasheet) says:

"The product is factory calibrated at 2.2 V. The operational power supply range is from 1.9 V to 3.6 V."

But what happens if I use 3.3v instead 2.2v?, in the datasheet does not says anything about recalibrate the sensor for other power supply

thanks

[Eleon BORLINI]

Hi @jg_spitfire​ , there are no difference in terms of performances or accuracy across the Vdd voltage range, especially as regard the motion parameters or the dependency vs Temperature. The only varying parameter is of course the current consumption, which is little higher at 3.3V than 2.2V, but 3.3V is a safe condition for LSM9DS1: consider that ST application kit and reference designs mounting the LSM9DS1 are typically powered 3.3V (that is the typical STM32 not low power voltage) and that you can in case tune the current consumption during acquisition also acting on the speed of the communication protocol (SPI or I2C). Regards

[jg_spitfire]

Hi, but the Electrical characteristics does not mention if the consumption is using the I2C or SPI protocol, how do I know which one consumes less?

thanks

[Eleon BORLINI]

Hi @jg_spitfire​ , the electrical value don't include, in general, the current consumption due to the chosen particular communication protocol (and the related speed), because it is due to external factors. Since the I2C includes pull-up resistors, for the same amount of speed (e.g. 100kHz) the SPI protocol is less current consuming, but if you need higher frequency (e.g. >1MHz) the SPI is the only available protocol and you have to include an increasing-with-frequency consumption (this is valid, in general, for every devices...). Regards

[jg_spitfire]

Hi @Eleon BORLINI​ I understand that with 3.3V I am in the safe zone of voltage but it is very strange that ST calibrates this device to 2.2V especially if you mention that 3.3V is a typical voltage used for ST, in general is very strange that ST says in the datasheet "calibrate to 2.2V" but after says "use any voltage inside the allowed range", thanks

[Eleon BORLINI]

Hi @jg_spitfire​ , 3.3V is the typical high-level voltage of the MCUs (STM32, but if this is true for the STM32F4 or F7 or H7 families, for other families such as L4 or G4 the typ voltage is 1.8V). This is not in general true for the sensors: consider that the evolution of the MEMS sensors market has gone towards a reduction of the power consumption (mainly driven by the personal electronics and IoT application segments), and the technology has undergone a similar trend-line. This is the reason why the typ Vdd is close to 1.8V (LSM9DS1 is not one of the newest products, so Vdd typ is 2.2V). This is not true in general for sensors that target an industrial or an automotive market, where the typ logic voltages are higher (3.3V but also 5V) and the sensor technology has been calibrated as a consequence. Regards