ADV7120

REV. B

–10–

PC BOARD LAYOUT CONSIDERATIONS

The ADV7120 is optimally designed for lowest noise perfor-

mance, both radiated and conducted noise. To complement the

excellent noise performance of the ADV7120, it is imperative

that great care be given to the PC board layout. Figure 8 shows

a recommended connection diagram for the ADV7120.

The layout should be optimized for lowest noise on the

ADV7120 power and ground lines. This can be achieved by

shielding the digital inputs and providing good decoupling. The

minimized so as to minimize inductive ringing.

Ground Planes

The ADV7120 and associated analog circuitry, should have a

separate ground plane referred to as the analog ground plane.

This ground plane should connect to the regular PCB ground

plane at a single point through a ferrite bead, as illustrated in

Figure 8. This bead should be located as close as possible

(within 3 inches) to the ADV7120.

The analog ground plane should encompass all ADV7120

ground pins, voltage reference circuitry, power supply bypass

circuitry, the analog output traces and any output amplifiers.

The regular PCB ground plane area should encompass all the

digital signal traces, excluding the ground pins, leading up to

the ADV7120.

GND

FS ADJUST

IOR

IOG

IOB

GROUND

ADV7120

C3

0.1

µF

C5

0.1

µF

Z1 (AD589)

R1

75

Ω

R2

75

Ω

R3

75

Ω

C1

33

µF

C2

10

µF

COMP

C6

0.1

µF

ANALOG POWER PLANE

V

AA

V

REF

L2 (FERRITE BEAD)

R0

R7

G0

G7

B0

B7

CLOCK

REF WHITE

SYNC

BLANK

RGB

VIDEO

OUTPUT

VIDEO

DATA

INPUTS

VIDEO

CONTROL

INPUTS

ANALOG GROUND PLANE

C4

0.1

µF

R

SET

560

Ω

L1 (FERRITE BEAD)

+5V (V

I

SYNC

SET

COMPONENT

C1

C2

C3, C4, C5, C6

L1, L2

R1, R2, R3

Rset

Z1

SET

DESCRIPTION

33

µF TANTALUM CAPACITOR

10

µF TANTALUM CAPACITOR

0.1

µF CERAMIC CAPACITOR

FERRITE BEAD

75

Ω 1% METAL FILM RESISTOR

560

Ω 1% METAL FILM RESISTOR

1.235V VOLTAGE REFERENCE

VENDOR PART NUMBER

FAIR-RITE 274300111 OR MURATA BL01/02/03

DALE CMF-55C

DALE CMF-55C

ANALOG DEVICES AD589JH

Figure 8. ADV7120 Typical Connection Diagram and Component List