View detail for AT42QT1040

ATMEL TOUCH TECHNOLOGY
 AT42QT1040
Low-cost Touch Sensor Controller for Mobile Devices
The AT42QT1040 (QT1040) IC is a convenient and easy-to-use touch sensor controller for up to four
capacitive touch keys. The device comes in an ultra-small 20-pin 3 mm x 3 mm VQFN package, making
it ideal for use in space-constrained mobile devices. This new low-cost IC makes it possible to replace
mechanical buttons in mobile and consumer devices with Atmel’s QTouch™ technology.
n4-channel touch sensor IC
n4 outputs for per-channel touch indication
nLow operating voltage 1.8 to 5.5 V
nUltra-low power consumption
(31 mA, 64 ms between acquisitions, 1.8 V)
nOption to configure output as proximity sensor
n2 response speed settings
nDebug output provided to aid design
nRoHS-compliant package
Key Sensitivity
Reliability
The channels on the QT1040 are individually
configurable for sensitivity to support a wide range of
front panel materials and thicknesses. It is possible
to configure any one of the channels as a proximity
sensor that can be used to illuminate “hidden until
lit” keys on an approaching hand.
As with all Atmel devices, the QT1040 is extremely
reliable, thanks to Atmel’s patented technology.
Response Speed
The response speed can be configured either
for low latency (16 ms), or for a slightly slower
response (64 ms) with the benefit of reduced power
consumption. The setting used depends on product
requirements.
Tightly spaced key pads can prove a challenge
when using capacitive touch buttons: nearby fingers
can cause false detections, or a hovering hand can
activate channels. Atmel’s patented Adjacent Key
Suppression™ (AKS™) technology overcomes
these issues. AKS isolates the key with the largest
signal, and then suppresses signals from all other
keys whilst the selected key is pressed, so false key
detections do not occur.
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Self-calibration
Debugging Output
The device automatically self-calibrates within
0.1 seconds of applying power. If a touch key is
miscalibrated at power-on (for example, if a finger
is held over the key), the device automatically
recalibrates as the finger is removed. Similarly, a
recalibration takes place if a channel is triggered for
longer than a specified time-out period.
The QT1040’s debugging mode can be used to
watch selected variables in the device. Data is
clocked at a rate of 200 kHz, which means that
channels can be monitored with great accuracy. The
ability to log the behavior of the device in this way
means quicker isolation and resolution of issues,
and a shorter design life cycle.
Auto Drift Compensation
Drift compensation algorithms constantly adjust the
reference level in the device to ensure that the keys
remain calibrated even if there is a large change in
background capacitance.
Headquarters
Atmel Corporation
2325 Orchard Parkway
San Jose, CA 95131
USA
Tel: +1 408 441-0311
Fax: +1 408 487-2600
International
Atmel Asia
Unit 01-05 & 16, 19/F
BEA Tower, Millennium City 5
418 Kwun Tong Road
Kwun Tong
Kowloon
Hong Kong
Tel: +852 2245-6100
Fax: +852 2722-1369
Atmel Europe
Le Krebs
8, Rue Jean-Pierre Timbaud
BP 309
78054 St Quentin-enYvelines Cedex
France
Tel: +33 1-30-60-70-00
Fax: +33 1-30-60-71-11
System
Number of keys
Up to 4
Number of I/O lines
4 output channels
Key outline sizes
Typically 8–10 mm advised, although they can be smaller; and of varied shapes
Key spacings
7 mm center to center typical; depends on panel thickness
Signal processing
Adjacent Key Suppression, noise filtering, self-calibration on start-up, automatic drift
compensation
Electrical and Environmental Specifications
Atmel Japan
9F, Tonetsu Shinkawa Bldg.
1-24-8 Shinkawa
Chuo-ku, Tokyo 104-0033
Japan
Tel: +81 3-3523-3551
Fax: +81 3-3523-7581
Touch Technology Division
1 Mitchell Point
Ensign Way
Hamble
Southampton
Hampshire SO31 4RF
United Kingdom
Tel: +44 23-8056-5600
Fax: +44 23-8045-3939
Product Contact
Recommended Operating Conditions
Power supply
1.8V to 5.5V
Power supply ripple + noise
±5 mV
Product Line
[email protected]
Literature Requests
www.atmel.com/literature
Environmental Specifications
Operating temperature
-40ºC to +85ºC
Storage temperature
-55ºC to + 125ºC
Web Site
www.atmel.com
DC Specifications
Supply current, slow mode, 64 ms between acquisitions
31 µA @ 1.8V
Supply current, fast mode, 16 ms between acquisitions
104 µA @ 1.8V
Package Options
20-pin 3 mm x 3 mm x 0.85 mm VQFN RoHS compliant
More Information?
© 2009 Atmel Corporation.
All rights reserved.
Atmel®, Atmel logo and combinations
thereof, Adjacent Key Suppression™,
AKS™, QTouch™ and others are registered trademarks or trademarks of
Atmel Corporation or its subsidiaries.
Other terms and product names may
be trademarks of others.
Rev.: 10616A-AT42-03/09/0M
The QT1040 datasheet is available from our website – www.atmel.com/products/touch
There is also an evaluation kit available (EVK1040A) that allows you to experiment with different configurations
and settings. It is supplied ready to use, with documentation.
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