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

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TMF8801
Application Information
Datasheet PUBLIC
DS000648 v8-00 • 2021-Jul-08
69 56
9 Application Information
9.1 SPAD Options
9.1.1 Signal SPADs
Firmware can enable/disable SPADs in the array as needed.
Figure 112:
Signal SPADs
Min
Nom
Max
Comment
1x SPADS
72
10x Attenuated SPADs
16
100x Attenuated SPADs
16
Physically there are 4x32=128 signal SPADs, but SPADs with too high dark count rate are disabled
during production test. There are four TDCs (TDC1…TDC4) connected to the output of the SPADs.
Each of the TDCs is connected to an array of 32 SPADs (SPADs with too high dark count rate are
disabled). In distance mode the number of SPADs are reduced to typ. 40 SPADs to limit the FOV of
the TMF8801.
9.1.2 Reference SPADs
Figure 113:
Reference SPADs
Min
Nom
Max
Comment
100x Attenuated SPADs
9
Due to the high light intensity form the VCSEL which is located very close to the reference SPADs and
has no optical barrier like the signal SPADs only highly attenuated SPADs are used. Physically there
are 12 reference SPADs, but SPADs with too high dark count rate are disabled during production test.
There is one TDC (TDC0) connected to the output of the SPADs.