mpc8379e Freescale Semiconductor, Inc, mpc8379e Datasheet - Page 77

• Manufacturer Part Number: mpc8379e
• Description: Powerquicc Ii Pro Processor Hardware Specifications
• Manufacturer: Freescale Semiconductor, Inc

clock driver chip manufacturer to verify whether this connection scheme is compatible with a particular
clock driver chip.
Figure 56
It assumes the DC levels of the clock driver are compatible with device SerDes reference clock input’s DC
requirement.
20.2.4
The clock driver selected should provide a high quality reference clock with low phase noise and
cycle-to-cycle jitter. Phase noise less than 100 KHz can be tracked by the PLL and data recovery loops and
is less of a problem. Phase noise above 15 MHz is filtered by the PLL. The most problematic phase noise
Freescale Semiconductor
LVPECL CLK Driver Chip
Clock Driver
Single-Ended CLK
Driver Chip
Clock Driver
Clock Driver
Figure 55. AC-Coupled Differential Connection with LVPECL Clock Driver (Reference Only)
shows the SerDes reference clock connection reference circuits for a single-ended clock driver.
AC Requirements for SerDes Reference Clocks
CLK_Out
CLK_Out
CLK_Out
MPC8379E PowerQUICC II Pro Processor Hardware Specifications, Rev. 3
Figure 56. Single-Ended Connection (Reference Only)
33 Ω
R1
R1
100 Ω differential PWB trace
Total 50 Ω. Assume clock driver’s
output impedance is about 16 Ω.
R2
R2
50 Ω
100 Ω differential PWB trace
10 nF
10 nF
SD n _REF_CLK
SD n _REF_CLK
SD n _REF_CLK
SD n _REF_CLK
50 Ω
50 Ω
High-Speed Serial Interfaces (HSSI)
50 Ω
50 Ω
MPC8379E
MPC8379E
SerDes Refer.
CLK Receiver
SerDes Refer.
CLK Receiver
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