Texas Instruments LMX2595 EVM, Руководство пользователя

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Appendix E
13 SNAU219B – June 2017 – Revised March 2020
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Connecting Reference Pro
Table 7. Output Type 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 8 with the output type from Table 7 .
Table 8 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 8. 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 µF
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 µF
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 µF
R27. R30, R31 DNP
Figure 17. LMK61PD0A2 Output Termination