ZHCSKF3B April 2017 – October 2019 LMH0397
PRODUCTION DATA.
OUT0 is a 100-Ω driver output. In EQ Mode, OUT0 serves as a host-side output from the SDI_IO cable equalizer. In CD Mode, OUT0 serves as a host-side loopback output. OUT0 also supports polarity inversion.
NOTE
In EQ Mode, OUT0 is enabled by default, regardless of the logic applied to the OUT0_SEL pin.
The driver offers users the capability to select higher output amplitude and de-emphasis levels for longer board trace that connects the drivers to their downstream receivers. Driver de-emphasis provides transmitter equalization to reduce the ISI caused by the board trace.
In EQ Mode, the HOST_EQ0 pin determines the output amplitude (VOD) and de-emphasis levels applied to the OUT0 PCB driver. In CD Mode, the VOD and de-emphasis levels for OUT0 are set by default to 570 mVp-p and –0.4 dB. These settings can be changed through register control if desired.
Table 10 details the OUT0 VOD and de-emphasis settings that can be applied. The HOST_EQ0 pin settings can be overridden by register control. When these parameters are controlled by registers, the VOD and de-emphasis levels can be programmed independently. For more information, refer to the LMH0397 Programming Guide (SNLU225).
| EQ/CD_SEL
(MODE) |
HOST_EQ(1) | OUT0± VOD
(mVp-p) |
OUT0± DEM
(dB) |
|---|---|---|---|
| L
(EQ Mode) |
H | 400 | 0 |
| F | 570 | –0.4 | |
| R | 660 | –2.1 | |
| L | 830 | –4.4 | |
| H
(CD Mode) |
X | 570 | –0.4 |