MPC8313E-RDBB Freescale Semiconductor, MPC8313E-RDBB Datasheet - Page 42

• Manufacturer Part Number: MPC8313E-RDBB
• Description: BOARD CPU 8313E VER 2.1
• Manufacturer: Freescale Semiconductor
• Series: PowerQUICC II™ PROr
• Type: MPUr

Specifications of MPC8313E-RDBB

• Contents: Board
• Processor To Be Evaluated: MPC8xxx
• Data Bus Width: 32 bit
• Interface Type: Ethernet, USB, JTAG, SPI, UART
• Dimensions: 170 mm x 170 mm
• Operating Supply Voltage: 3.3 V
• For Use With/related Products: MPC8313E
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

High-Speed Serial Interfaces (HSSI)
Figure 29
Since LVPECL driver’s DC levels (both common mode voltages and output swing) are incompatible with
the MPC8313E SerDes reference clock input’s DC requirement, AC coupling has to be used.
assumes that the LVPECL clock driver’s output impedance is 50 Ω. R1 is used to DC-bias the LVPECL
outputs prior to AC coupling. Its value could be ranged from 140 to 240 Ω depending on the clock driver
vendor’s requirement. R2 is used together with the SerDes reference clock receiver’s 50-Ω termination
resistor to attenuate the LVPECL output’s differential peak level such that it meets the MPC8313E
SerDes3 reference clock’s differential input amplitude requirement (between 200 and 800 mV differential
peak). For example, if the LVPECL output’s differential peak is 900 mV and the desired SerDes reference
clock input amplitude is selected as 600 mV, the attenuation factor is 0.67, which requires R2 = 25 Ω.
Consult with the clock driver chip manufacturer to verify whether this connection scheme is compatible
with a particular clock driver chip.
42
LVPECL CLK Driver Chip
LVDS CLK Driver Chip
Clock Driver
Clock Driver
Clock Driver
Clock Driver
Clock Driver
Figure 29. AC-Coupled Differential Connection with LVPECL Clock Driver (Reference Only)
Figure 28. AC-Coupled Differential Connection with LVDS Clock Driver (Reference Only)
shows the SerDes reference clock connection reference circuits for LVPECL type clock driver.
CLK_Out
CLK_Out
CLK_Out
CLK_Out
CLK_Out
CLK_Out
MPC8313E PowerQUICC
10 nF
10 nF
R1
R1
100 Ω Differential PWB Trace
100 Ω Differential PWB Trace
R2
R2
R2
R2
™
II Pro Processor Hardware Specifications, Rev. 3
10 nF
10 nF
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
SerDes Refer.
CLK Receiver
SerDes Refer.
CLK Receiver
MPC8313E
MPC8313E
Figure 29