mpc8378e Freescale Semiconductor, Inc, mpc8378e Datasheet - Page 86

• Manufacturer Part Number: mpc8378e
• Description: Powerquicc Ii Pro Processor Hardware Specifications
• Manufacturer: Freescale Semiconductor, Inc

High-Speed Serial Interfaces (HSSI)
Figure 59
assumes that the DC levels of the clock driver chip is compatible with device SerDes reference clock
input’s DC requirement.
Figure 60
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
output driver features a 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 61
Since LVPECL driver’s DC levels (both common mode voltages and output swing) are incompatible with
device SerDes reference clock input’s DC requirement, AC-coupling has to be used.
86
LVDS CLK Driver Chip
HCSL 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 59. DC-Coupled Differential Connection with HCSL Clock Driver (Reference Only)
Figure 60. 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
MPC8378E PowerQUICC II Pro Processor Hardware Specifications, Rev. 3
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
50 Ω
50
Ω
Freescale Semiconductor
Figure 61
MPC8378E
MPC8378E
SerDes Refer.
CLK Receiver
SerDes Refer.
CLK Receiver
assumes