User guide

Si471x-EVB
Preliminary Rev. 0.4 9
3.2.3. Reference Clock for the Si471x
Figure 10. Reference Clock Block Diagram
The Si471x accepts a 32.768 kHz reference clock at the RCLK pin. On the EVB, this clock is provided by a
precision crystal oscillator. The user has the option of not using the oscillator and bringing in the reference clock
from an external source through SMA connector J54.
When the user chooses to provide an external RCLK jumper J52 has to be set accordingly. Also the user has the
option to turn off the onboard crystal oscillator by installing jumper J57.
DAUGHTER BOARD
Si471x
RCLK
9
X1
32.768kHz
INT RClk
Jumper
J52
J54
EXT
RClk
Jumper
J57
DIS_INT_RCLK
INT_RCLK
EXT_RCLK