ADV7340EBZ datasheet(67/88 Pages) AD

67 / 88 page

ADV7340/ADV7341

Rev. 0 | Page 67 of 88

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10M

100M

FREQUENCY (Hz)

CIRCUIT FREQUENCY RESPONSE

GROUP DELAY (Seconds)

PHASE (Degrees)

MAGNITUDE (dB)

21n

18n

15n

12n

24n

Figure 87. Output Filter Plot for SD, 16× Oversampling

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10M

100M

FREQUENCY (Hz)

CIRCUIT FREQUENCY RESPONSE

MAGNITUDE (dB)

GROUP DELAY (Seconds)

PHASE

(Degrees)

320

240

160

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480

400

14n

12n

10n

18n

16n

Figure 88. Output Filter Plot for ED, 8× Oversampling

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FREQUENCY (MHz)

CIRCUIT FREQUENCY RESPONSE

100

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200

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120

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GROUP DELAY (Seconds)

PHASE

(Degrees)

MAGNITUDE (dB)

Figure 89. Output Filter Plot for HD, 4× Oversampling

PRINTED CIRCUIT BOARD (PCB) LAYOUT

The ADV7340/ADV7341 are highly integrated circuits

containing both precision analog and high speed digital

circuitry. They have been designed to minimize interference

effects on the integrity of the analog circuitry by the high speed

digital circuitry. It is imperative that these same design and

layout techniques be applied to the system-level design so that

optimal performance is achieved.

The layout should be optimized for lowest noise on the

ADV7340/ADV7341 power and ground planes by shielding the

digital inputs and providing good power supply decoupling.

It is recommended to use a 4-layer printed circuit board with

ground and power planes separating the signal trace layer and

the solder side layer.

Component Placement

Component placement should be carefully considered to

separate noisy circuits, such as clock signals and high speed

digital circuitry from analog circuitry.

The external loop filter components and components connected

to the COMP, VREF, and RSET pins should be placed as close as

possible to and on the same side of the PCB as the

ADV7340/ADV7341. Adding vias to the PCB to get the

components closer to the ADV7340/ADV7341 is not

recommended.

It is recommended that the ADV7340/ADV7341 be placed as

close as possible to the output connector, with the DAC output

traces as short as possible.

The termination resistors on the DAC output traces should be

placed as close as possible to and on the same side of the PCB as

the ADV7340/ADV7341. The termination resistors should

overlay the PCB ground plane.

External filter and buffer components connected to the DAC

outputs should be placed as close as possible to the

ADV7340/ADV7341 to minimize the possibility of noise

pickup from neighboring circuitry, and to minimize the effect

of trace capacitance on output bandwidth. This is particularly

important when operating in low drive mode (RSET = 4.12 kΩ,

RL = 300 Ω).

Power Supplies

It is recommended that a separate regulated supply be provided

for each power domain (VAA, VDD, VDD_IO, and PVDD). For

optimal performance, linear regulators rather than switch mode

regulators should be used. If switch mode regulators must be

used, care must be taken with regard to the quality of the output

voltage in terms of ripple and noise. This is particularly true for

the VAA and PVDD power domains. Each power supply should be

individually connected to the system power supply at a single

point through a suitable filtering device, such as a ferrite bead.

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