GS1508-CTAE3 GENNUM [Gennum Corporation], GS1508-CTAE3 Datasheet - Page 6

• Manufacturer Part Number: GS1508-CTAE3
• Description: HDTV Cable Driver
• Manufacturer: GENNUM [Gennum Corporation]

TYPICAL APPLICATION CIRCUIT
TABLE 2: Typical Application Circuit Component Values
APPLICATION INFORMATION
PCB LAYOUT
Special attention must be paid to component layout when
designing serial digital interfaces for HDTV. Figures 8
through 11 show the artwork for a four layer printed circuit
evaluation board for the GS1508. The schematic is shown in
Figure 7. An FR-4 dielectric can be used, however,
controlled impedance transmission lines are required for
PCB traces longer than approximately 1cm. Note the
following
performance:
PCB trace width for HD rate signals is closely matched to
SMT component width to minimize reflections due to
change in trace impedance
The PCB ground plane is removed under the GS1508
output components to minimize parasitic capacitance.
The PCB ground plane is removed under the GS1508 R
pin and resistor to minimize parasitic capacitance
Input and output BNC connectors are surface mounted in-
line to eliminate a transmission line stub caused by a BNC
mounting via High speed traces are curved to minimize
impedance changes due to change of PCB trace width.
522 - 02 - 03
COMPONENT
C
L
R
COMP
COMP
Z
SET
0
PCB
PECL INPUT
artwork
VALUE
0.5pF
12nH
53.6
50
Z
0
1n
features
Z
For 800mV Output
For 50
Typical value. Component value will vary depending on PCB layout.
Typical value. Component value will vary depending on PCB layout.
0
53.6
PCB trace impedance
used
1
2
3
4
SDI
SDI
V
R
EE
SET
GS1508
to
optimize
SDO
SDO
GND
V
CC
COMMENT
SET
8
7
6
5
100n
6
75
0µ1
V
CC
V
CC
75
All resistors in ohms,
all capacitors in farads,
unless otherwise shown.
C
C
L
L
COMP
COMP
COMP
COMP
75
75
+
+
4µ7
4µ7
OUT
OUT