AT42QT1040-MMH Atmel, AT42QT1040-MMH Datasheet - Page 64

• Manufacturer Part Number: AT42QT1040-MMH
• Description: IC TOUCH SENSOR 4KEY 20-VQFN
• Manufacturer: Atmel
• Series: QTouch™r
• Type: Resistiver

Specifications of AT42QT1040-MMH

• Touch Panel Interface: 4, 2-Wire
• Number Of Inputs/keys: 4 Key
• Data Interface: I²C, Serial
• Data Rate/sampling Rate (sps, Bps): 200k
• Voltage Reference: Internal
• Voltage - Supply: 1.8 V ~ 5.5 V
• Current - Supply: 10mA
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 20-VQFN Exposed Pad, 20-HVQFN, 20-SQFN, 20-DHVQFN
• Output Type: Logic
• Input Type: Logic
• Supply Voltage: 1.8 V to 5.5 V
• Dimensions: 3 mm L x 3 mm W x 0.8 mm H
• Output Voltage: 0.7 V to 0.8 V
• Temperature Range: - 40 C to + 85 C
• Termination Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Interface: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: AT42QT1040-MMH; AT42QT1040-MMHTR

10620D–AT42–04/09
Mutual-capacitance One-dimensional Sensors
6.4
6.4.1
6.4.2
6-10
Typical Resistively Interpolated Method
Introduction
One-Layer Medium/Large Slider Or Wheel
This method uses an array of key segments connected by resistors. The advantage of this method is
that each key (or channel) in the sensor is formed by one or more segments. This makes it possible to
construct larger sliders and wheels than would be possible with the spatially interpolated method
described in
The basic design is the same as that shown in
page
resistive dividers on the X lines.
Figure 6-8.
Figure 6-9.
Smallest inner diameter is
determined by the point at
which the X fingers taper
to minimum width. For larger
inner diameters, set diameter
to desired size and taper
X fingers to suit.
Extra Resistive Segment(s) For X Electrode
6-2. However, to increase the length or diameter of the sensor, extra segments are created using
Xn-1
Section 6.3 on page
One-layer Medium/Large Slider (Resistively Interpolated)
One-layer Medium/Large Wheel (Resistively Interpolated)
Rtotal typically 100 kW
For X Electrode
Extra Resistive
6-2.
Segment(s)
Xn-2
X0
X1
Section 6.3.2 “One-Layer Small Slider Or Wheel” on
Rtotal 2 k to 10
W
X0
kW
Touch Sensors Design Guide
For design rules, see
Figure 6-1 on page 6-2
For design rules, see
Figure 6-2 on page 6-4