CY8CMBR2110_13 Datasheet, PDF (25/71 Pages) Cypress Semiconductor – CapSense® Express™ 10-Button Controller

CY8CMBR2110
Layout Guidelines and Best Practices
Table 8. Layout Guidelines and Best Practices
Sl. No.
Category
Min
1 Button Shape
–
2 Button Size
3 Button-Button spacing
4 Button Ground Clearance
5 mm
Equal to
Button
Ground
Clearance
0.5 mm
5 Ground Flood - Top layer
6 Ground Flood - Bottom layer
7 Trace Length from button pad to
CapSense controller pins
8 Trace Width
9 Trace Routing
–
–
–
0.17 mm
–
10 Via Position for the buttons
11 Via Hole Size for button traces
12 No. of via on button trace
13 Distance of CapSense series
resistor from button pin
14 Distance between any CapSense
trace to ground Flood
15 Device placement
–
–
1
–
10 mil
–
16 Placement of components in two
–
layer PCB
17 Placement of components in four
–
layer PCB
18 Overlay thickness
19 Overlay material
20 Overlay adhesives
21 LED back lighting
22 Board thickness
0 mm
–
–
–
–
Max
–
15 mm
–
Recommendations/Remarks
Solid round pattern, round with LED hole, rectangle
with round corners
Refer to the Design Toolbox
8 mm (Y dimension in Figure 39 on page 26)
2 mm
–
–
450 mm
Refer to the Design Toolbox (X dimension in Figure 39
on page 26)
Hatched ground 7 mil trace and 45 mil grid (15% filling)
Hatched ground 7 mil trace and 70 mil grid (10% filling)
Refer to the Design Toolbox
0.20 mm
–
–
–
2
10 mm
20 mil
0.17 mm (7 mil)
Traces should be routed on the non-button side. If any
non-CapSense trace crosses CapSense trace, ensure
that intersection is orthogonal.
Via should be placed near the edge of the button to
reduce trace length thereby increasing sensitivity
10 mil
1
Place CapSense series resistors close to the device for
noise suppression. Place CapSense resistors, which
have highest priority, first.
20 mil
–
–
–
5 mm
–
–
–
–
Mount the Device on the layer opposite to button. The
CapSense trace length between the Device and
buttons should be minimum (see trace length above)
Top Layer – buttons
Bottom layer – device, other components and traces.
Top Layer – buttons
Second Layer – CapSense traces and V_DD (avoid V_DD
traces below the buttons)
Third Layer – hatched ground
Bottom layer – CapSense controller, other components
and non CapSense traces
Refer to the Design Toolbox
Should be non-conductive material. Glass, ABS
Plastic, Formica, wood and so on. There should be no
air gap between PCB and overlay. Use adhesive to
stick the PCB and overlay.
Adhesive should be non conductive and dielectrically
homogenous. 467MP and 468MP adhesives made by
3M are recommended.
Cut a hole in the button pad and use rear mountable
LEDs. Refer to the PCB layout in the following section.
Standard board thickness for CapSense FR4 based
designs is 1.6 mm.
Document Number: 001-74494 Rev. *B
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