CY3280-BBM Cypress Semiconductor Corp, CY3280-BBM Datasheet - Page 4

• Manufacturer Part Number: CY3280-BBM
• Description: MODULE BREADBOARD CAPSENSE
• Manufacturer: Cypress Semiconductor Corp
• Series: CapSense™r

Specifications of CY3280-BBM

• Mfg Application Notes: Capacitance Sensing - AppNote CapSense Best Practices - AppNote
• Design Resources: CY3280-BBM Schematic
• Accessory Type: Prototyping Board
• Interface Type: Serial
• Operating Voltage: 5 V
• Silicon Manufacturer: Cypress
• Silicon Core Number: CAP1073264
• Kit Application Type: Sensing - Touch / Proximity
• Application Sub Type: Capacitive Touch
• Rohs Compliant: No
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: CY3280 Module Board
• For Use With: 428-2987 - CAPSENSE CONTROLLER DEV KIT
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 428-2992

Page: 4
4. Review CapSense Best Practices
The Universal CapSense Controller was created using the best practices for
CapSense layout. To enable universality and development of the kit and its projects,
certain design elements have been changed from what is recommended for final prod-
ucts. Below is a list of the design features in the Universal CapSense Controller and
what to change for final products.
Sensing traces
routed through
a connector to
sensors.
Sensing traces
routed to other
schematic
elements.
Sensing traces
located on the
top layer.
Several
regulators
used, including
a variable
regulator.
Test point on
CMOD.
Feature
Design
Buttons, sliders, and
LEDs are placed on the
module board to allow for
greater flexibility with
custom modules for
development and
subsequent releases.
Universality of the board
enabled by population/
depopulation of 0-Ω
resistors.
Using vias to route
traces to bottom of board
and back to connector
increases parasitic
capacitance.
Demonstration of
CapSense at several
voltages.
Accessibility of charge/
discharge waveforms.
Reason
Connectors increase the
parasitic capacitance of
the sensors, effectively
reducing their sensitivity.
Connectors also create
another path for noise to
enter the system.
Solder pads of 0-Ω
resistors increase
parasitic capacitance.
Possible noise sensitivity
to stimulus on top side of
board. Finger presses on
routing of control board
can lead to sensor
activation.
Global and User Module
parameters may need to
be verified with changing
power supply.
A test point increases
noise sensitivity by
acting as an antenna.
Impact
Sensors and control
circuitry should be
located on the same
printed circuit board.
Lower parasitic
capacitance by reducing
trace lengths.
Route traces directly to
sensing elements. Use
as few 0-Ω resistors as
possible.
Route sensing traces on
non-user side of printed
circuit board. Route
sensing traces as far
from noise sources as
possible.
Supply one regulated
voltage to PSoC.
Solder pad test points
for leads offer better
noise immunity if test
points are required.
Recommended
Change