Freescale Freedom Development Board FRDM-CR20A User’s Guide, Rev. 0, 04/2015
22
Freescale Semiconductor, Inc.
PCB manufacturing specifications
IMPORTANT
: The FRDM-CR20A development board contains high frequency 2.4 GHz RF circuitry.
As a result, RF component placement, line geometries and layout, and spacing to the ground plane are
critical parameters. BOARD STACKUP GEOMETRY IS CRITICAL. Dielectric and copper thicknesses
and spacing must not be changed; follow the stackup (see
Figure 17
) information provided with the
reference design.
Figure 17. FRDM-CR20A PCB stackup cross-section (four layer)
•
Solder mask is required
•
Silk screen is required
5.2
Panelization
The panel size can be negotiated depending on production volume.
5.3
Materials
The PCB composite materials must meet the following requirements:
•
Laminate—the base laminate material must be FR4. If the laminate material is changed, the RF
electrical characteristics may change and degrade RF performance.
•
Copper foil
— Top and bottom copper layers must be 1 oz. copper
•
Plating—All pad plating must be Hot Air Levelling (HAL)
5.4
Solder mask
The solder mask must meet the following requirements:
•
Solder mask type: Liquid Film Electra EMP110 or equivalent
•
Solder mask thickness: 10 – 30 µm
5.5
Silk screen
The silk screen must meet the following requirements:
•
Silk screen color: White
•
Silk screen must be applied after application of solder mask if solder mask is required
•
The silk screen ink must not extend into any plated-thru-holes
•
The silk screen must be clipped back to the line of resistance
Downloaded from
Downloaded from
Downloaded from
Downloaded from
Downloaded from
Downloaded from
Downloaded from
Downloaded from
Downloaded from
Downloaded from
Downloaded from
Downloaded from
Downloaded from
Downloaded from
Downloaded from
Downloaded from
Downloaded from
Downloaded from
Downloaded from
Downloaded from
Downloaded from
Downloaded from