GS1522 Gennum Corporation, GS1522 Datasheet - Page 15

• Manufacturer Part Number: GS1522
• Description: Hd-linx (tm) THDTV Serial Digital Serializer
• Manufacturer: Gennum Corporation

When the outputs are used to differentially drive another
device such as the GS1508, use 50Ω transmission lines
with the smallest possible signal swing while allowing 10%
variation at the output swing to select the correct R
resistor. To drive the GS1508, the recommended R
resistor is 150Ω. There is no need to compensate for the
return-loss in this situation. The uncompensated waveform at
the output is shown in Figure 24.
TABLE 4: R
GENNUM CORPORATION
R
SET
Fig. 23 Signal Swing for Various R
1.0
0.8
0.6
0.4
0.2
0.0
500.0 Ω
150.0 Ω
RESISTOR
75.0 Ω
53.6 Ω
52.3 Ω
49.9 Ω
SET
0.00
Values for Various Output Load Conditions
75Ω
0.01
THE R
(= 1/R
ADMITTANCE (g) OF
1/RSET (Ω)
SET
50Ω
SET
0.0020
0.0067
0.0133
0.0187
0.0192
0.0200
RESISTOR)
RESISTOR
SET
0.02
Admittances
0.03
OUTPUT CURRENT
SET
SET
15.161mA
20.702mA
21.216mA
22.032mA
2.506mA
7.896mA
15
NOTE: Figures 24 and 25 show the waveforms on an
oscilloscope using a 75Ω to 50Ω pad.
Fig. 24 Uncompensated Output Eye Waveform
Fig. 25 Compensated Output Eye Waveform
TRANSMISSION LINE,
TERMINATED AT THE
RESISTOR AT THE
SOURCE = 75Ω)
END. (PULL-UP
0.094V
0.296V
0.569V
0.776V
0.796V
0.826V
TRANSMISSION LINE,
TERMINATED AT THE
RESISTOR AT THE
SOURCE = 50Ω)
END. (PULL-UP
0.063V
0.197V
0.379V
0.517V
0.530V
-
522 - 26 - 02