qt140 Quantum Research Group, qt140 Datasheet - Page 11

• Manufacturer Part Number: qt140
• Description: 4 And 5 Key Qtouch? Sensor Ics
• Manufacturer: Quantum Research Group

4.5 SIGNAL PROCESSING
lQ
Description
Threshold differential
Hysteresis
Consensus filter length (Detection integrator)
Positive drift compensation rate
Negative drift compensation rate
Post-detection recalibration timer duration
18000
16000
14000
12000
10000
8000
6000
4000
2000
0
0
10
Burst Duration v s. Cs, Cx
Figure 4-1
20
Cx
18000
16000
14000
12000
10000
8000
6000
4000
2000
30
0
0
40
50
50
All curves at Vdd = 5.0V
10, 60, infinite
Cs = 220nF
Cs = 100nF
Cs = 47nF
Cs = 39nF
Cs = 22nF
Cs = 10nF
Burst Duration cs. Cs, Cx
Value
100
990
231
6
2
3
Figure 4-3
Cs, nF
11
150
samples
ms/level
ms/level
counts
counts
Units
secs
4000
3500
3000
2500
2000
1500
1000
500
0
0
200
From signal reference
From threshold
Option pin selected
10
Burst Duration v s. Cs, Cx
Figure 4-2
250
20
Cx
Cx = 5pF
Cx = 10pF
Cx = 15pF
Cx = 22pF
Cx = 33pF
Cx = 47pF
30
Notes
QT140/150 1.01/1102
40
50
Cs = 47nF
Cs = 39nF
Cs = 22nF
Cs = 10nF