QT60248C-ASG Atmel, QT60248C-ASG Datasheet - Page 40
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QT60248C-ASG
Manufacturer Part Number
QT60248C-ASG
Description
IC TOUCH SENSOR 24KEY 32TQFP
Manufacturer
Atmel
Series
QMatrix™, QProx™r
Type
Capacitiver
Specifications of QT60248C-ASG
Number Of Inputs/keys
24 Key
Resolution (bits)
9, 11 b
Data Interface
Serial, SPI™
Voltage - Supply
3 V ~ 5 V
Current - Supply
25mA
Operating Temperature
-40°C ~ 105°C
Mounting Type
Surface Mount
Package / Case
32-TQFP, 32-VQFP
Output Type
*
Interface
*
Input Type
*
For Use With
427-1087 - BOARD EVAL QT60248-AS QMATRIX
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
QT60248C-ASG
Manufacturer:
Atmel
Quantity:
5 700
10620D–AT42–04/09
Mutual-capacitance Zero-dimensional Sensors
4.2.4.3
4-8
Avoiding False Key Detection
To avoid false keys, use any of the following tricks:
In addition, keep to the following general guidelines:
1. Watch out for time constants.
2. Behind from the point of view of touch.
Figure 4-9.a. 90° Crossing (Best)
Figure 4-9.c. X Under Ground Trace
Cross the X and Y traces as little as possible and then only at 90° (see
If the X and Y traces must run parallel to each other for a distance, separate the traces with a ground
trace. Where possible, use a ground trace that is twice as wide as the track-to-track gap
(see
Consider routing the X traces behind ground planes
traces is minimized, even if the Y traces run close to the X traces adjacent to the ground flood
(see
Route the Y traces completely behind
so they do not interact (see
Keep the X and Y traces thin where possible.
Route the Y traces farthest from touch where possible.
Generally, keep all the X traces together and all the Y traces together. This way the number of
potential false keys is substantially reduced.
Figure
Figure
Gaps are much bigger than a touch
Y
4-9.b).
4-9.c).
Y
X
X
Panel
Ground
Figure
Substrate
4-9.d).
(2)
the X traces if needed, or route the X and Y traces well apart
Figure 4-9.b. Separating ground Trace
Figure 4-9.d. Y Under X
(1)
. This means that the field between the X and Y
Y
Ground
Y
Figure
Touch Sensors Design Guide
Note:
Avoid long runs!
X
X
4-9.a).