mpc8378 Freescale Semiconductor, Inc, mpc8378 Datasheet - Page 84

• Manufacturer Part Number: mpc8378
• Description: Powerquicc Ii Pro Processor
• Manufacturer: Freescale Semiconductor, Inc

High-Speed Serial Interfaces (HSSI)
Figure 56
assumes that the DC levels of the clock driver chip is compatible with device SerDes reference clock
input’s DC requirement.
Figure 57
Since LVDS clock driver’s common mode voltage is higher than the device SerDes reference clock input’s
allowed range (100 to 400 mV), AC-coupled connection scheme must be used. It assumes the LVDS
84
HCSL CLK Driver Chip
Total 50 Ω. Assume clock driver’s
output impedance is about 16 Ω.
Clock Driver
Clock Driver
Figure 56. DC-Coupled Differential Connection with HCSL Clock Driver (Reference Only)
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
Figure 56
fact that clock driver chip's internal structure, output impedance, and
termination requirements are different between various clock driver chip
manufacturers, it is very possible that the clock circuit reference designs
provided by the clock driver chip vendor are different from what is shown
below. They might also vary from one vendor to the other. Therefore,
Freescale Semiconductor can neither provide the optimal clock driver
reference circuits, nor guarantee the correctness of the following clock
driver connection reference circuits. The system designer is recommended
to contact the selected clock driver chip vendor for the optimal reference
circuits with the device SerDes reference clock receiver requirement
provided in this document.
MPC8377E PowerQUICC II Pro Processor Hardware Specifications, Rev. 3
to
33 Ω
33 Ω
Figure 59
Clock driver vendor dependent
source termination resistor
100 Ω differential PWB trace
below are for conceptual reference only. Due to the
NOTE
SD n _REF_CLK
SD n _REF_CLK
50 Ω
50 Ω
Freescale Semiconductor
MPC8377E
SerDes Refer.
CLK Receiver