QT60248C-ASG Atmel, QT60248C-ASG Datasheet - Page 27

• 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

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