QST104 STMicroelectronics, QST104 Datasheet - Page 28

• Manufacturer Part Number: QST104
• Description: Capacitive touch sensor device 4 keys
• Manufacturer: STMicroelectronics

Design guidelines
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It is important to limit the amount of stray capacitance on the SNS terminals, for example by
minimizing trace lengths and widths to allow for higher gain without requiring higher values
of C
cause the other key to trigger. Therefore, electrode traces from adjacent keys should not be
run close to each other over long runs in order to minimize cross-coupling if large values of
delta-C
problem when the electrodes are working through a plastic panel with normal touch
sensitivity.
For additional information on PCB layout and construction, please contact your local ST
Sales Office for a list of available application notes.
S
. Under heavy delta-C
X
are expected, for example when an electrode is directly touched. This is not a
X
loading of one key, cross coupling to another key’s trace can
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