GS1508 HD-LINX™ HDTV Cable Driver

Data Sheet

9500 - 6

August 2010

11 of 14

5.2 PCB Layout

Special attention must be paid to component layout when designing serial digital interfaces

for HDTV. Figure 5-3 through Figure 5-6 show the artwork for a four-layer printed circuit

evaluation board for the GS1508. The schematic is shown in Figure 5-2. An FR-4 dielectric

can be used, however, controlled impedance transmission lines are required for PCB traces

longer than approximately 1cm. Note the following PCB artwork features used to optimize

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

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, which are

curved to minimize impedance changes due to change of PCB trace width

5.3 GS1508 Evaluation Board

5.3.1 EB1508 PCB Schematic

Figure 5-2: Schematic Diagram for the GS1508 Evaluation Board

R10

75

L2 10n

R9

75

C17 0p5

L3 10n

C18 0p5

EDGEMNT_BNC

EDGEMNT_BNC

J4

J5

C11

4µ7

C12

4µ7

C10

100n

R8

75

R7

C15

10n

75

SDO

SDO

GND

SDI

SDI

VEE

RSET VCC

R12

50

R13

50

C16

1n

1µ

1µ

EDGEMNT_BNC

C13

C14

J6

J7

EDGEMNT_BNC

TP1

TP2

C1

C2

C3

1µ

100n

1n

All resistors in Ohms and

all capacitors in Farads

unless otherwise shown.

R11

53.6

U2