AT42QT1012-MAH Atmel, AT42QT1012-MAH Datasheet - Page 14

• Manufacturer Part Number: AT42QT1012-MAH
• Description: IC SENSR TOUCH/PROX 1CH SOT23-8
• Manufacturer: Atmel
• Series: QTouch™r
• Type: Capacitiver

Specifications of AT42QT1012-MAH

• Touch Panel Interface: 1, 2-Wire
• Number Of Inputs/keys: 1 Key
• Resolution (bits): 9, 14 b
• Data Interface: Serial
• Voltage Reference: Internal
• Voltage - Supply: 1.8 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-UFDFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Supply: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

14
AT42QT1012
Figure 3-8.
The charts in
high or active low output.
Example using the formula to calculate Rt and Ct
Requirements:
Proceed as follows:
As an alternative to calculation,
curves of auto-off delay against resistor and capacitor values for active high and active low
outputs at various values of VDD (delay multiplier = x1).
• Active high output (Vop connected to VSS)
• Auto-off delay nominal 45 minutes
• VDD = 3.5V
1. Calculate Auto-off delay in seconds 45 x 60 = 2700
2. Obtain K from
3. Calculate Rt x Ct =
4. Decide on a value for Rt or Ct (for example, Ct = 47 nF)
5. Calculate Rt =
6. Verify that
24
23
22
21
20
19
2
2.5
Figure 3-8
Typical Values of K Versus Supply Voltage
Active High Output
RtxCt
--------------- -
3
K
Figure
4104
------------ -
VDD (Volts)
47
3.5
= 179 (which is between 4 and 240)
show typical values of K versus supply voltage for a QT1012 with active
2700 22.8
------------------------------ -
= 87 k
3-8, K= 22.8
15
4

Figure 3-9
4.5
= 4104
5
and
Figure 3-10 on page 16
19.35
19.25
19.15
19.05
19.4
19.3
19.2
19.1
2
2.5
Active Low Output
3
VDD (Volts)
3.5
show charts of typical
4
9543D–AT42–08/10
4.5
5