LIS3DH ADC Specifications

[chris2]

Posted on October 30, 2013 at 03:02

Are the specs for the ADC in the LIS3DH available?  I'm particularly interested in input voltage range, input current, and recommended capacitance for ADC inputs.

[refd123]

Posted on September 23, 2016 at 00:51

I just asked this very thing from the support web site.  They responded with how to access the temp sensor!?  So I asked again what is the input voltage range, what is the measurement reference, ratiometric or voltage reference?  What voltage?  How do you change the mux channels?  Why are there no detailed commands for the ADC in section 8 of the 2010 data sheet?

Since Chris has not seen an answer since 2013 should I be waiting 3 years for my answer?  My tech support response did say to come to the eCommunity or pay a consultant.  Wait ... I am a consultant.

[Miroslav BATEK]

Posted on October 10, 2016 at 19:30

The LIS3DH contains an auxiliary ADC with 3 separate dedicated inputs: pins ADC1, ADC2, ADC3.

The user can retrieve the converted data from registers OUT_ADC1_L (08h), OUT_ADC1_H (09h), OUT_ADC2_L (0Ah), OUT_ADC2_H (0Bh) and OUT_ADC3_L (0Ch),OUT_ADC3_H (0Dh).

In order to use the auxiliary ADC, the user must set the BDU bit (bit 7) to 1 in CTRL_REG4 (23h) and the ADC_EN bit (bit 7) to 1 in TEMP_CFG_REG (1Fh). The ADC sampling frequency is the same as that of the ODR in CTRL_REG1 (20h).

The input range is: 1200 mv ±400 mV and the data output is expressed in 2's complement left-aligned.

The ADC resolution is 10 bits if the LPen (bit 3) in CTRL_REG1 (20h) is cleared (high performance / normal mode), otherwise, in low-power mode, the ADC resolution is 8-bit.

Channel 3 of the ADC can be connected to the temperature sensor by setting the TEMP_EN bit (bit 6) to 1 in TEMP_CFG_REG (1Fh).

Best regards

Miroslav