QST104 STMicroelectronics, QST104 Datasheet - Page 33

• Manufacturer Part Number: QST104
• Description: Capacitive touch sensor device 4 keys
• Manufacturer: STMicroelectronics

QST104
6.5
Capacitive sensing characteristics
Table 25.
Table 26.
MaxOnDuration Max on-duration delay
NegComDrift
PosComDrift
PosRecalTh
NegDiffDrift
PosDiffDrift
BurstCount
PosRecalI
ComFact
EofDeTh
NegDriftI
PosDriftI
Symbol
Symbol
DiffFact
t
DeTh
t
Setup
EDI
CAL
C
C
C
R
DI
S
X
S
T
External sensing components
Capacitive sensing parameters
Calibration duration
Setup duration
Detection integrator
Detection threshold
End of detection integrator
Positive recalibration integrator
Positive recalibration threshold
Positive differential drift compensation rate
Negative differential drift compensation rate
Positive common drift compensation rate
Negative common drift compensation rate
Positive drift integrator
Negative drift integrator
Common time step factor
Differential time step factor
End of detection threshold
Burst length
Sense capacitor
Equivalent electrode capacitor
Equivalent touch capacitor
Serial resistance
Parameter
Parameter
Min.
Min.
-128
-128
0.1
0.1
0.1
0.1
0
0
0
1
1
0
0
0
0
20
Electrical characteristics
Default Max.
Infinite
Typ.
100
-10
0.2
0.2
10
10
10
10
-8
2
2
2
6
1
1
2
5
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TBD
Max.
25.5
25.5
25.5
25.5
2000
255
255
128
255
255
255
255
255
255
100
100
-1
-1
22
Counts
Counts
Counts
Counts
Counts
Counts
Counts
s/level
s/level
s/level
s/level
kOhm
Unit
Unit
ms
ms
nF
pF
pF
s
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