CC2564MODN Datasheet, PDF (32/62 Pages) Texas Instruments – Bluetooth Host Controller Interface (HCI) Module

CC2564MODN, CC2564MODA
SWRS160D – FEBRUARY 2014 – REVISED DECEMBER 2015
www.ti.com
6.2.1.2 RF Interface Guidelines
6.2.1.2.1 RF Trace (CC2564MODN Only)
Route the RF traces on layer 1 (top) and keep the routes as short as possible. These traces must be 50-
Ω, controlled-impedance traces with reference to the solid ground in the layer 2-microstrip transmission
line. The TI reference design uses an RF trace width equal to 17 mils, which conforms to a 50 Ω-±3%
simulated result, based on the following PCB properties: (see Table 6-1 and Figure 6-4).
• Substrate height: 10 mils
• Substrate dielectric: 4.2
• Trace width: 17 mils
• Trace thickness: 1.4 mils
• Ground clearance: 20 mils
TI recommends the following guidelines for a good RF trace design:
• The RF traces must have via stitching on both ground planes around the RF trace (see Figure 6-4).
• Avoid placing clock signals close to the RF path.
• Place a u.FL connector (or similar) between the module and antenna if possible or during prototype
phases (see Figure 6-4.)
• The RF path should look like one single path along the RF traces and matching components. See
Figure 6-5 for the good (OK) case versus the not good (NG) case.
• The RF trace bends must be gradual with an approximate maximum bend of 45 degrees with trace
mitered. RF traces must not have sharp corners. In addition:
– Avoid case (1) in Figure 6-6. A right angle leads to scattering and makes matching weak.
– Case (2) in Figure 6-6 is not recommended. Even if this bend had a good 50 Ω, a careful simulation
would be required.
– Case (3) in Figure 6-6 is recommended. The half-arc angle reduces scattering caused by a right
angle.
Figure 6-4. Placing a u.FL Connector Between the Module and Antenna
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Applications, Implementation, and Layout
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