Texas Instruments LMX2594 - Page 20

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SNAU210–March 2017
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Connecting Reference Pro
Table 5. Output Frequency of LMK61PD0A2 (Reference Pro)
FS1 FS0 OUTPUT FREQUENCY (MHz)
0 0 100
0 NC 312.5
0 1 125
NC 0 106.25
NC NC 156.25
NC 1 212.5
1 0 62.5
Table 6. OutputType of LMK61PD0A2 (Reference Pro)
OS OE OUTPUT TYPE
X O Disabled (PLL Functional)
0 1 LVPECL
NC 1 LVDS
1 1 HCSL
The OS pin is used to bias internal drivers and change the output type. It is imperative to match the output
termination passive components as shown on Table 7 with the output type from Table 6.
Table 7 lists component values for each configuration.
(1)
50 Ω to V
CC
– 2? V termination is required on receiver.
(2)
100-Ω differential termination (R31) is provided on Reference Pro PCB. Removing the differential termination on the EVM is
possible if the differential termination is available on the receiver.
Table 7. Output Termination Schemes
OUTPUT FORMAT COUPLING COMPONENT VALUE
LVPECL AC
(default EVM
configuration)
R25, R28 0 Ω
R26, R29 150 Ω
C24, C25 0.01 uF
R27, R30, R31 DNP
DC
(1)
R25, R28, C24, C25 0 Ω
R26, R29, R27, R30, R31 DNP
LVDS
(2)
AC R25, R28, R27, R30 0 Ω
R31 100 Ω
C24, C25 0.01 uF
R26, R29 DNP
DC R25, R27, R28, R30, C24, C25 0 Ω
R31 100 Ω
R26, R29 DNP
HCSL AC R25, R28 0 Ω
R26, R29 50 Ω
C24, C25 0 Ω
R27, R30, R31 DNP
DC R25, R28 0 Ω
R26, R29 50 Ω
C24, C25 0.01 uF
R27. R30, R31 DNP