AD9380SLASHPCB datasheet(56/60 Pages) AD

56 / 60 page

AD9380

Rev. 0 | Page 56 of 60

OUTPUTS (BOTH DATA AND CLOCKS)

Try to minimize the trace length that the digital outputs have to

drive. Longer traces have higher capacitance, which require

more current that causes more internal digital noise.

Shorter traces reduce the possibility of reflections.

Adding a series resistor of value 50 Ω to 200 Ω can suppress

reflections, reduce EMI, and reduce the current spikes inside

the AD9380. If series resistors are used, place them as close as

possible to the AD9380 pins (although try not to add vias or

extra length to the output trace to move the resistors closer).

If possible, limit the capacitance that each of the digital outputs

drives to less than 10 pF. This can be accomplished easily by

keeping traces short and by connecting the outputs to only one

device. Loading the outputs with excessive capacitance increases

the current transients inside of the AD9380 and creates more

digital noise on its power supplies.

DIGITAL INPUTS

The digital inputs on the AD9380 were designed to work with

3.3 V signals, but are tolerant of 5.0 V signals. Therefore, no

extra components need to be added if using 5.0 V logic.

Any noise that enters the HSYNC input trace can add jitter to

the system. Therefore, minimize the trace length and do not run

any digital or other high frequency traces near it.

AD9380/PCB bảng dữ liệu(PDF) 56 Page - Analog Devices