ZHCSIC9D April 2016 – June 2018 LMH1219
PRODUCTION DATA.
The VOD_DE control pin selects the output amplitude and de-emphasis settings for both OUT0 and OUT1. It 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.
By default, the output driver VOD and de-emphasis settings are configured by the VOD_DE pin logic settings shown in Table 5. These settings can be overridden via register control by applying the appropriate override bit values. When these parameters are controlled by registers, the VOD and de-emphasis levels for each channel can be programmed independently. For more information, refer to the LMH1219 Register Map and the Programming Guide.
VOD_DE
LEVEL |
VOD REG SETTING
OUT0±: 0x30[5]=1, 0x30[2:0] OUT1±: 0x32[5]=1, 0x32[2:0] |
DEM REG SETTING
OUT0±: 0x31[6]=1, 0x31[2:0] OUT1±: 0x33[6]=1, 0x33[2:0] |
VOD (mVpp)(2) | VODDE (mVpp)(2) | DEM (dB) | FR4 TRACE LENGTH (inches) |
---|---|---|---|---|---|---|
H | 0 | 0 | 410 | 410 | 0 | 0 – 1 |
F | 2 | 2 | 560 | 500 | -0.9 | 2 – 4 |
R | 3 | 3 | 635 | 480 | -2.4 | 5 – 6 |
L | 5 | 5 | 810 | 480 | -6.1 | 7 – 8 |