9 Reference PRO
The Reference PRO board is used to program the LMX2594PSEVM and provide a clean reference clock
to LMX2594PSEVM at the same time. The board has several control pins dedicated for control of output
format, output frequency, and output enable control. These control pins are configurable through the jumpers
by strapping the center pin to Vdd position or GND position. Connections from the Vdd position to the device
supply or from the GND position to the ground plane are connected by 1.5-kΩ resistors. By default, the board is
configured for 100-MHz LVPECL output. The power supply to Reference PRO is obtained from the PC through a
USB connection.
Figure 9-1. Reference PRO Board
9.1 Output Frequency Selection
Jumpers FS1 and FS0 are used to set the output frequency.
Table 9-1. Reference PRO Output Frequency Selection
FS1
FS0
OUTPUT FREQUENCY (MHz)
GND
GND
100
GND
NC
312.5
GND
Vdd
125
NC
GND
106.25
NC
NC
156.25
NC
Vdd
212.5
Vdd
GND
62.5
Reference PRO
16
LMX2594PSEVM Evaluation Instructions
SNAU278 – JULY 2022
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