User manual
DocID026171 Rev 6 29/79
VL6180X Functional description
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2.12.5 Cross-talk limit
A practical limit for cross-talk is < 3.0 Mcps. This is based on two factors:
1. The return rate for a 3% reflective target at 100 mm without glass is typically around 1.5
Mcps. If glass is added with a cross-talk of 3.0 Mcps, the resultant return rate will be 4.5
Mcps. This results in a cross-talk correction factor of x3 so for a 100 mm target the raw
range will be in the region of 30 mm. To ensure the
SYSRANGE__CROSSTALK_VALID_HEIGHT restriction is not breached, the minimum
raw range allowing for noise margin is around 30 mm.
2. A cross-talk correction factor of x3 also means that any range noise will be multiplied
by 3 so noise also becomes a limiting factor.
2.12.6 Cross-talk vs air gap
Figure 18 shows the typical cross-talk vs air gap using ST cover glass with oval aperture.
Above 2.5 mm, the cross-talk rises rapidly.
Figure 18. Cross-talk vs air gap
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