E6248 Atmel, E6248 Datasheet - Page 27

• Manufacturer Part Number: E6248
• Description: BOARD EVAL QT60248-AS QMATRIX
• Manufacturer: Atmel
• Series: Quantum, QMatrix™r

Specifications of E6248

• Sensor Type: Touch, Capacitive
• Sensing Range: 16 / 24 Buttons/Keys
• Interface: SPI Serial
• Voltage - Supply: 3 V ~ 5 V
• Embedded: No
• Utilized Ic / Part: QT60168, QT60248
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Sensitivity: -
• Other names: 427-1087

7.2 1-Sided Key Layout
This key design can be made on a 1-sided SMT PCB. A single 0-ohm jumper
allows the wiring to be done on a single side with full pass-through of X and Y
traces to allow matrix connections to be made across a large number of keys.
Key size, shape, and number of interleavings can be varied substantially from
this drawing. The below drawing shows 6 interleave white spaces; only a
double interleave is required in the case of smaller keys.
The PCB is bonded to a panel on its underside, and the fields fire through the
PCB, adhesive, and panel in that sequence. This results in a very low cost
design.
7.3 PCB Layout
Shown is an example PCB layout using inexpensive 1-sided CEM-1 or FR-1 PCB laminate. The key layouts follow the design
rules shown above. (PCB design shown uses a QT60326 chip but still represents a good example).
lQ
27
X
QT60248-AS R4.02/0405
Y
Y
0-ohm SMT Jumper
X