mpc8641 Freescale Semiconductor, Inc, mpc8641 Datasheet - Page 65

• Manufacturer Part Number: mpc8641
• Description: Integrated Host Processor Hardware Specifications
• Manufacturer: Freescale Semiconductor, Inc

Figure 43
assumes that the DC levels of the clock driver chip is compatible with MPC8641D SerDes reference clock
input’s DC requirement.
Figure 44
Since LVDS clock driver’s common mode voltage is higher than the MPC8641D SerDes reference clock
input’s allowed range (100 to 400 mV), AC-coupled connection scheme must be used. It assumes the
LVDS output driver features 50-Ω termination resistor. It also assumes that the LVDS transmitter
establishes its own common mode level without relying on the receiver or other external component.
Figure 45
Since LVPECL driver’s DC levels (both common mode voltages and output swing) are incompatible with
Freescale Semiconductor
HCSL CLK Driver Chip
LVDS CLK Driver Chip
Total 50 Ω. Assume clock driver’s
output impedance is about 16 Ω.
Clock Driver
Clock Driver
Clock Driver
Clock Driver
Figure 43. DC-Coupled Differential Connection with HCSL Clock Driver (Reference Only)
Figure 44. AC-Coupled Differential Connection with LVDS Clock Driver (Reference Only)
shows the SerDes reference clock connection reference circuits for LVPECL type clock driver.
shows the SerDes reference clock connection reference circuits for HCSL type clock driver. It
shows the SerDes reference clock connection reference circuits for LVDS type clock driver.
CLK_Out
CLK_Out
CLK_Out
CLK_Out
CLK_Out
MPC8641 and MPC8641D Integrated Host Processor Hardware Specifications, Rev. 2
33 Ω
10 nF
10 nF
33 Ω
Clock driver vendor dependent
source termination resistor
100 Ω differential PWB trace
100 Ω differential PWB trace
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
MPC8641D
MPC8641D
SerDes Refer.
CLK Receiver
SerDes Refer.
CLK Receiver
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