Data Sheet

Calibration functions UM2356
18/28 DocID031478 Rev 1
3 Calibration functions
To benefit from the full performance of the device, the VL53L1X driver includes calibration
functions that should be run once at the customer production line.
Calibration procedures have to be run to compensate the part-to-part parameters and the
presence of the cover glass that may affect the device performance.
Calibration data stored in the host have to be loaded into theVL53L1X at each startup using
a dedicated driver function.
Three calibrations are needed: RefSPAD, offset, and crosstalk.
The order the calibration functions are called is important: RefSPAD should be called first,
offset second, and crosstalk third.
The three calibration functions can be done sequentially one after another, or individually.
When run individually, the previous step data have to be loaded before running the current
calibration.
3.1 RefSPAD calibration
The number of SPADs is calibrated during the final module test at ST. This part-to-part value
is stored in the NVM and automatically loaded into the device during boot.
This calibration allows adjustment of the number of SPADs to optimize the device dynamic.
However, adding a cover glass on top of the module may affect this calibration. We
recommend that the customer performs this calibration again in the final product application.
The same algorithm running at FMT is applied when this function is called. The algorithm
searches through the three possible types of SPAD:
1. Non attenuated SPAD
2. SPAD attenuated by a factor of 5
3. SPAD attenuated by a factor of 10
The number and type of SPAD is selected to avoid internal signal saturation.
3.1.1 RefSPAD calibration function
A dedicated function is available for this operation:
VL53L1_PerformRefSpadManagement(&VL53L1Dev)
Note: This function must be called first in the calibration procedure.