11 Layout

11.1 Layout Guidelines

The following section provides the layout guidelines to ensure good thermal performance and power supply

connections for the CDCDB800.

In Layout Examples, the CDCDB800 has 85-Ω differential output impedance LP-HCSL format drivers as per

register default settings. All transmission lines connected to CKx pins should be 85-Ω differential impedance,

42.5-Ω single-ended impedance to avoid reflections and increased radiated emissions. If 100-Ω output

impedance is enabled, the transmission lines connected to CKx pins should be 100-Ω differential impedance,

50-Ω single-ended impedance. Take care to eliminate or reduce stubs on the transmission lines.

11.2 Layout Examples

Figure 11-1 through Figure 11-3 are printed circuit board (PCB) layout examples that show the application of

thermal design practices and a low-inductance ground connection between the device DAP and the PCB.

Figure 11-1. PCB Layout Example for CDCDB800, Top layer

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CDCDB800

SNAS818 – JULY 2021

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Product Folder Links: CDCDB800