ADV7128KR80 Analog Devices Inc, ADV7128KR80 Datasheet - Page 7

• Manufacturer Part Number: ADV7128KR80
• Description: IC DAC VIDEO 80MHZ 5.0V 28SOIC
• Manufacturer: Analog Devices Inc
• Type: Video DACr

Specifications of ADV7128KR80

• Rohs Status: RoHS non-compliant
• Resolution (bits): 10 b
• Sampling Rate (per Second): 80M
• Voltage Supply Source: Single Supply
• Voltage - Supply: 4.75 V ~ 5.25 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 28-SOIC (7.5mm Width)
• Data Interface: -

REV. 0
PC Board Layout Considerations
The ADV7128 is optimally designed for lowest noise perfor-
mance, both radiated and conducted noise. To complement the
excellent noise performance of the ADV7128 it is imperative
that great care be given to the PC board layout. Figure 7 shows
a recommended connection diagram for the ADV7128.
The layout should be optimized for lowest noise on the
ADV7128 power and ground lines. This can be achieved by
shielding the digital inputs and providing good decoupling. The
lead length between groups of V
minimized so as to minimize inductive ringing.
Ground Planes
The ADV7128 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 7. This bead should be located as close as possible
(within 3 inches) to the ADV7128.
INPUTS
TERMINATION)
VIDEO
DATA
DAC
(SOURCE
Z
S
Z
= 75
2
I
OUT
CLOCK
ADV7128
D0
D9
Figure 6. AD848 As an Output Buffer
COMP
V
RSET
2
3
GND
V
REF
I
AD848
OUT
AA
+V
–V
4
7
S
S
560
R
Z
SET
1
0.1 F
0.1 F
Figure 7. ADV7128 Typical Connection Diagram and Component List
C6
0.1 F
C3
0.1 F
6
AA
and GND pins should be
ANALOG POWER PLANE
GAIN (G) = 1+
75
R1
C4
0.1 F
75
ANALOG GROUND PLANE
Z
Z
C5
0.1 F
1
Z1
(AD589)
2
Z
(CABLE)
O
= 75
(MONITOR)
Z
L
= 75
VIDEO
OUTPUT
L1 (FERRITE BEAD)
–7–
L2 (FERRITE BEAD)
C2
10 F
The analog ground plane should encompass all ADV7128
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 ADV7128.
Power Planes
The PC board layout should have two distinct power planes,
one for analog circuitry and one for digital circuitry. The analog
power plane should encompass the ADV7128 (V
sociated analog circuitry. This power plane should be connected
to the regular PCB power plane (V
a ferrite bead, as illustrated in Figure 7. This bead should be lo-
cated within three inches of the ADV7128.
The PCB power plane should provide power to all digital logic
on the PC board, and the analog power plane should provide
power to all ADV7128 power pins, voltage reference circuitry
and any output amplifiers.
The PCB power and ground planes should not overlay portions
of the analog power plane. Keeping the PCB power and ground
planes from overlaying the analog power plane will contribute to
a reduction in plane-to-plane noise coupling.
Supply Decoupling
Noise on the analog power plane can be further reduced by the
use of multiple decoupling capacitors. (See Figure 7.)
Optimum performance is achieved by the use of 0.1 F ceramic
capacitors. Each of the two groups of V
decoupled to ground. This should be done by placing the ca-
pacitors as close as possible to the device with the capacitor
leads as short as possible, thus minimizing lead inductance.
COMPONENT
C3, C4, C5,C6
L1, L2
R
C1
33 F
SET
C1
C2
R1
Z1
+5V (V
GROUND
DESCRIPTION
33 F TANTALUM CAPACITOR
10 F TANTALUM
0.1 F CERAMIC CAPACITOR
FERRITE BEAD
75 1% METAL FILM RESISTOR
560 1% METAL FILM RESISTOR
1.235V VOLTAGE REFERENCE
CC
)
CC
) at a single point through
AA
VENDOR PART NUMBER
FAIR-RITE 274300111 OR
DALE CMF-55C
DALE CMF-55C
ANALOG DEVICES AD589JH
should be individually
MURATA BL01/02/03
ADV7128
AA
) and all as-