MSC8152 datasheet(58/68 Pages) FREESCALE

58 / 68 page

MSC8152 Dual-Core Digital Signal Processor Data Sheet, Rev. 5

Hardware Design Considerations

Freescale Semiconductor

3.3

Clock and Timing Signal Board Layout Considerations

When laying out the system board, use the following guidelines:

•

Keep clock and timing signal paths as short as possible and route with 50

Ω impedance.

•

Use a serial termination resistor placed close to the clock buffer to minimize signal reflection. Use the following

equation to compute the resistor value:

Rterm = Rim – Rbuf

where Rim = trace characteristic impedance

Rbuf = clock buffer internal impedance.

3.4

SGMII AC-Coupled Serial Link Connection Example

Figure 39 shows an example of a 4-wire AC-coupled serial link connection. For additional layout suggestions, see AN3556

MSC815x High Speed Serial Interface Hardware Design Considerations, available on the Freescale website or from your local

sales office or representative.

Figure 39. 4-Wire AC-Coupled SGMII Serial Link Connection Example

SGMII

SerDes Interface

Transmitter

SR[1–2]_TX[[1–2]

SR[1–2]_RX[1–2]

SR[1–2]_TX[1–2]

SR[1–2]_RX[1–2]

Receiver

CTX

SR[1–2]_RX[1–2]

SR[1–2]_RX[1–2]]

Receiver

Transmitter

SR[1–2]_TX[1–2

]

SR[1–2]_TX[1–2]

CTX

MSC8152 Datasheet(PDF) 58 Page - Freescale Semiconductor, Inc