Xilinx FMC XM104, Руководство пользователя, Страница: 18 / 21

18 www.xilinx.com FMC XM104 Connectivity Card User Guide
UG536 (v1.1) September 24, 2010
Chapter 1: XM104
9. Clocking Circuits
Two programmable clock circuits are provided on the XM104:
• Silicon Labs Si570
• Silicon Labs Si5368
A Silicon Labs Si570 serial IIC bus re-programmable clock source provides a low-jitter
clock with a user-programmable output frequency from 10 to 810 MHz. The Si570 is
located at IIC address 0x5D. The Si570 clock output (shown in
Figure 1-2, page 10 ) is wired
to a NB6L11 clock driver integrated circuit. One differential output of the NB6L11 clock
driver is AC coupled, with 0.1 uF capacitors, and wired to the FMC HPC connector signal
GBTCLK1_M2C. The second output of the NB6L11 clock driver is connected one of the
Si5368 differential clock inputs. The default clock frequency is 156.25 MHz. Connections to
the FMC HPC connector are defined in
Table 1-11 .
The component installed on the XM104 is factory programmed with parameters in
Table 1-12 .
For additional information on this component, including reprogramming the clock
frequency through the IIC serial bus interface, consult the manufacturer's data sheet at:
www.silabs.com .
Table 1-11: Si570 Clock Source Routed to XM104 FMC HPC J1 Connector
FMC HPC Connector J1
Pin
Signal Name Source
B20 GBTCLK1_M2C_P
(1)
Si570
B21 GBTCLK1_M2C_N
(1)
Si570
Notes:
1. Signals are AC coupled using 0.1 uF series capacitors
Table 1-12: Characteristics of Si570 Component
Si570 Characteristic XM104
Output Format LVDS
Output Enable Polarity High
Temperature Stability 50 ppm
Frequency Range 10–810 MHz
Six-Digit Startup Frequency 156.250 MHz
Power Supply 3.3V
IIC Address x5D