2-18
Workstation 4 and 4 LX Field Service Guide
WS4 Technical Overview
TFT LCD Interface
The video output signals are fed to U1, a TI 75LVDS84A FlatLink Transmitter. This
device converts the 21-bits of TTL/CMOS timing and pixel data from the SC3200 into
three data and a single clock streams. These signals drive system board connector J5.
The primary reasons for converting the TTL/CMOS video signals to the LVDS format
are reduced noise and cable pin count. However, the LVDS compatible signals must
be converted back to TTL/CMOS compatible signals in order drive the LCD panel.
This is done in one of two ways depending on the type of LCD panel used.
Figure 2-12 depicts a unit with the Samsung LCD panel and companion LVDS
receiver board, XB34. The LVDS receiver board mounts to the LCD panel connector
and is attached to the LCD bracket with two screws.
Figure 2-13 on the following page, depicts units produced after October 2004. These
workstations use a Sharp LCD panel that includes an integrated LVDS receiver. The
LVDS receiver board is not required and would not fit the different connector on the
Sharp LCD.
Figure 2-12: WS4 LCD Interface - Samsung LCD Panel
TFTDE
O
Data Enable signals for Red, Blue, and
Green pixel data.
FP_VDD_ON
O
Enables power to the LCD panel with the
proper timing sequence.
Name
Type
Description
