E102 Atmel, E102 Datasheet - Page 11

• Manufacturer Part Number: E102
• Description: KIT EVAL/DEV USING QT102-ISG
• Manufacturer: Atmel
• Series: Quantum, QTouch™r

Specifications of E102

• Sensor Type: Touch, Capacitive
• Sensing Range: 1 Button/Key
• Interface: Logic Level
• Voltage - Supply: 3V
• Embedded: No
• Utilized Ic / Part: QT102
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Sensitivity: -

Example using a chart to calculate Rt and Ct
Requirements:
Note: the Auto-off delay times shown are nominal and will vary slightly from chip to chip and with capacitor and resistor
tolerance.
lQ
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•
•
1. Calculate Auto-off delay in seconds 10 x 60 x 60 = 36000. This value is outside of the range of the charts so use the x24
2. Find 36000 = 1500 on the 4V chart in Figure 3.13
3. This shows the following Rt / Ct combinations: 100nF / 10k, 47nF / 27k, 22nF / 60k or 10nF / 130k
4000
3500
3000
2500
2000
1500
1000
500
Active low output (Vop connected to VSS)
Auto-off delay 10 hours
VDD = 4V
multiplier (connect Rm to VDD).
Note: this will decrease the key sensitivity, so it may be necessary to increase the value of Cs.
4000
3500
3000
2500
2000
1500
1000
500
0
0
0
0
24
20
20
Ct=100nF
Ct=100nF
40
QT102 Active Low output, VDD = 3V
40
QT102 Active Low output, VDD = 5V
60
Tim ing Resistor Rt (K ohm s)
60
Tim ing Resistor Rt (K ohm s)
Ct=47nF
Ct=47nF
80
80
100
100
Figure 3.13 Auto-off Delay, Active Low Output,
120
120
Ct=22nF
140
140
160
Vm = Vss (delay multiplier = x1)
Ct=22nF
Ct=10nF
160
180
180
200
Ct=10nF
200
11
4000
3500
3000
2500
2000
1500
1000
4000
3500
3000
2500
2000
1500
1000
500
500
0
0
0
0
20
20
Ct=100nF
Ct=100nF
40
40
QT102 Active Low output, VDD = 4V
QT102 Active Low output, VDD = 2V
60
Tim ing Resistor Rt (K ohm s)
60
Tim ing Resistor Rt (K ohm s)
Ct=47nF
80
80
100
100
Ct=47nF
120
120
QT102_2R3.05_1007
140
140
Ct=22nF
160
160
Ct=10nF
Ct=22nF
180
180
Ct=10nF
200
200