Fermion TMF8801 ToF Distance Ranging Sensor (20-2500mm) - Datasheet

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TMF8801
Functional Description
Datasheet PUBLIC
DS000648 v8-00 • 2021-Jul-08
69 17
Parameter
Min
Nom
Max
Units
Comment
Standby to Active Time
<<1
ms
Active to Standby Time
<<1
ms
Enable Low to Power Down
Time
<<1
ms
7.6 Algorithm Performance
As the performance of the algorithm is dependent on the ROM version, following section only applies
for devices with order code TMF8801-1B (and TMF8801-1BM), calibrated and in-application oscillator
calibration using the reference driver code and patched with the latest software patch from ams
contact ams to identify latest patch version.
To achieve the full distance of 250 cm, the on chip oscillator needs to be tuned to 4.7 MHz.
The TMF8801 is embedded in the application using a 0.38 mm airgap and a glass with an IR ink with
>90 % transmissivity. The glass thickness is 0.5 mm. An additional mask on the opaque ink is
implemented according to TMF8801 optical design guide (external document).
7.6.1 Calibration
To achieve the performance described in the next sections, a calibration of the algorithm needs to be
performed (command = 0x0A). The TMF8801 shall be embedded in the final application and the cover
glass including the IR ink needs to be assembled. The calibration test shall be done in a housing with
minimal ambient light and no target within 40 cm in field of view of the TMF8801.
The TMF8801 generates a calibration data set which is permanently stored on the host.
On each power-up of the TMF8801 the calibration data set is sent by I²C to the TMF8801 prior to
execution of any algorithms (commands=0x02 or 0x0B).
7.6.2 Algorithm Timings
The TMF8801 can adjust the number of iterations and detection threshold using registers. A default
mode is defined having 900k iterations and threshold=0.