ATMEL AT42QT1012

Features
• Number of Keys:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
– One toggle mode (touch-on/touch-off), plus programmable auto-off delay and
external cancel
– Configurable as either a single key or a proximity sensor
Technology:
– Patented spread-spectrum charge-transfer (direct mode)
Key outline sizes:
– 6 mm x 6 mm or larger (panel thickness dependent); widely different sizes and
shapes possible
Electrode design:
– Solid or ring electrode shapes
PCB Layers required:
– One
Electrode materials:
– Etched copper, silver, carbon, Indium Tin Oxide (ITO)
Electrode substrates:
– PCB, FPCB, plastic films, glass
Panel materials:
– Plastic, glass, composites, painted surfaces (low particle density metallic paints
possible)
Panel thickness:
– Up to 12 mm glass, 6 mm plastic (electrode size and Cs dependent)
Key sensitivity:
– Settable via external capacitor (Cs)
Interface:
– Digital output, active high or active low (hardware configurable)
Moisture tolerance:
– Good
Power:
– 1.8V ~ 5.5V; 32.5 µA at 1.8V
Package:
– 6-pin SOT23-6 (3 x 3 mm) RoHS compliant
Signal processing:
– Self-calibration, auto drift compensation, noise filtering
Applications:
– Power switch replacement in countertop appliances, irons, battery powered toys,
heaters, lighting controls, automotive interior lighting, commercial and industrial
equipment such as soldering stations and cooking equipment
Patents:
– QTouch® (patented charge-transfer method)
One-channel
Toggle-mode
Touch Sensor
IC with Power
Management
Functions
AT42QT1012
Summary
Note: This is a summary document.
A complete document is available.
For more information contact
www.atmel.com/touch.
9543CS–AT42–02/10
1. Pinout and Schematic
1.1
OUT
1
VSS
2
SNSK
3
6
TIME
5
VDD
4
SNS
Pin Descriptions
Table 1-1.
2
QT1012
1.2
Pinout Configuration
Pin Listing
Pin
Name
Type
Comments
1
OUT
O
Output state. To switched circuit and output polarity selection
resistor (Rop)
2
Vss
P
Supply ground
3
SNSK
I/O
Sense pin. To Cs capacitor and to sense electrode
4
SNS
I/O
Sense pin. To Cs capacitor and multiplier configuration resistor
(Rm). Rm must be fitted and connected to either VSS or VDD.
5
Vdd
P
Power
6
TIME
I
Timeout configuration pin. Must be connected to either VSS,
VDD, OUT or an RC network.
I
Input only
I/O
Input and output
O
Output only, push-pull
P
Ground or power
AT42QT1012
9543CS–AT42–02/10
AT42QT1012
1.3
Schematic
Figure 1-1.
Basic Circuit Configuration
(active high output, toggle on/off, no auto switch off)
Note: bypass capacitor to be tightly
wired between VDD and VSS and
kept close to pin 5.
VDD
SENSE
ELECTRODE
5
VDD
RS
3
OUT 1
SNSK
CS
4
SNS
Rop
TIME 6
VSS
2
2. Overview of the AT42QT1012
2.1
Introduction
The AT42QT1012 (QT1012) is a single key device featuring a touch on/touch off (toggle) output
with a programmable auto switch-off capability.
The QT1012 is a digital burst mode charge-transfer (QT™) sensor designed specifically for touch
controls. It includes all hardware and signal processing functions necessary to provide stable
sensing under a wide variety of changing conditions; only low cost, noncritical components are
required for operation. With its tiny low-cost SOT-23 package, this device can suit almost any
product needing a power switch or other toggle-mode controlled function, especially power
control of small appliances and battery-operated products.
A unique “green” feature of the QT1012 is the timeout function, which can turn off power after a
specified time delay ranging from minutes to an hour.
Like all QTouch® devices, the QT1012 features automatic self-calibration, drift compensation,
and spread-spectrum burst modulation in order to provide for the most reliable touch sensing
possible.
3
9543CS–AT42–02/10
Revision History
4
Revision No.
History
Revision A – August 2009

Initial release for chip revision 2.4
Revision B – September 2009

Changes to Cs value.
Revision CS – February 2010

Updated for chip revision 3.1
AT42QT1012
9543CS–AT42–02/10
AT42QT1012
Notes
5
9543CS–AT42–02/10
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touch@atmel.com
Sales Contact
www.atmel.com/contacts
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Fax: (44) 23-8045-3939
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Literature Requests
www.atmel.com/literature
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9543CS–AT42–02/10