ADV7127 Analog Devices, ADV7127 Datasheet - Page 14

• Manufacturer Part Number: ADV7127
• Description: CMOS 240 MHz 10-Bit High Speed Video DAC
• Manufacturer: Analog Devices

Specifications of ADV7127

• Resolution (bits): 10bit
• Dac Update Rate: 240MSPS
• Dac Settling Time: 15ns
• Max Pos Supply (v): +5.25V
• Single-supply: Yes
• Dac Type: Current Out
• Dac Input Format: Par

ADV7127
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 ADV7127 (V
associated analog circuitry. This power plane should be con-
nected to the regular PCB power plane (V
through a ferrite bead, as illustrated in Figure 25. This bead
should be located within three inches of the ADV7127.
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 ADV7127 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.
INPUTS
VIDEO
DATA
C3, C4, C5, C6
COMPONENT
Figure 25. Typical Connection Diagram and Component List
L1, L2
R
PDOWN
PSAVE
CLOCK
D0
D9
SET
ADV7127
C1
C2
R1
CC
COMP
R
) at a single point
V
GND
DESCRIPTION
33 F TANTALUM CAPACITOR
10 F TANTALUM
0.1 F CERAMIC CAPACITOR
FERRITE BEAD
75
560
I
V
OUT
REF
SET
AA
1% METAL FILM RESISTOR
AA
1% METAL FILM RESISTOR DALE CMF-55C
) and all
560
R
SET
C3
0.1 F
C6
0.1 F
75
ANALOG POWER PLANE
R1
C4
0.1 F
–14–
Supply Decoupling
Noise on the analog power plane can be further reduced by the
use of multiple decoupling capacitors (see Figure 25).
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.
It is important to note that while the ADV7127 contains cir-
cuitry to reject power supply noise, this rejection decreases with
frequency. If a high frequency switching power supply is used,
the designer should pay close attention to reducing power sup-
ply noise. A dc power supply filter (Murata BNX002) will pro-
vide EMI suppression between the switching power supply and
the main PCB. Alternatively, consideration could be given to
using a three terminal voltage regulator.
ANALOG GROUND PLANE
VENDOR PART NUMBER
FAIR-RITE 274300111 OR MURATA BL01/02/03
DALE CMF-55C
C5
0.1 F
L1 (FERRITE BEAD)
L2 (FERRITE BEAD)
C2
10 F
VIDEO
OUTPUT
C1
33 F
GROUND
+5V (V
AA
CC
should be individually
)
REV. 0