AT42QT1040-MMH Atmel, AT42QT1040-MMH Datasheet - Page 3

• 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

Touch Sensors Design Guide
Table of Contents
Section 1
Introduction To Sensor Design................................................................................... 1-1
Section 2
General Advice........................................................................................................... 2-1
Section 3
Self-capacitance Zero-dimensional Sensors.............................................................. 3-1
1.1
1.2
1.3
1.4
2.1
2.2
2.3
2.4
2.5
3.1
3.2
3.3
Introduction ........................................................................................................................ 1-1
Self-capacitance and Mutual-capacitance Type Sensors .................................................. 1-1
Dimension Groups ............................................................................................................. 1-2
Some Important Theory ..................................................................................................... 1-2
Charge Transfer................................................................................................................. 2-1
Components....................................................................................................................... 2-3
Materials ............................................................................................................................ 2-4
Nearby LEDs...................................................................................................................... 2-7
Electrostatic Discharge Protection ..................................................................................... 2-8
Introduction ........................................................................................................................ 3-1
Planar Construction ........................................................................................................... 3-1
Non-planar Construction .................................................................................................... 3-7
2.2.1
2.2.2
2.2.3
2.2.4
2.3.1
2.3.2
2.3.3
2.3.4
3.2.1
3.2.2
3.2.3
3.2.4
3.2.5
3.2.6
3.2.7
3.3.1
Cs Capacitor ........................................................................................................ 2-3
Series Resistors................................................................................................... 2-3
Voltage Regulator ................................................................................................ 2-3
Component Placement ........................................................................................ 2-3
Substrates ........................................................................................................... 2-4
Electrode and Interconnection Materials ............................................................. 2-4
Front Panel Materials........................................................................................... 2-5
PCB to Panel Bonding ......................................................................................... 2-6
Introduction .......................................................................................................... 3-1
Electrode Shapes ................................................................................................ 3-2
Ground Loading ................................................................................................... 3-3
Interconnection .................................................................................................... 3-4
Illumination Effects............................................................................................... 3-5
Floating Conductive Items ................................................................................... 3-6
Conductive Paints................................................................................................ 3-7
Printed Electrode Method .................................................................................... 3-8
10620D–AT42–04/09
iii