AD9981SLASHPCB datasheet(10/44 Pages) AD

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AD9981

Rev. 0 | Page 10 of 44

Description

POWER SUPPLY

VD (3.3 V)

Main Power Supply.

These pins supply power to the main elements of the circuit. They should be as quiet and filtered as possible.

VDD (1.8 V–3.3 V)

Digital Output Power Supply.

A large number of output pins (up to 35) switching at high speed (up to 95 MHz) generate a lot of power supply

transients (noise). These supply pins are identified separately from the VD pins, so special care can be taken to

minimize output noise transferred into the sensitive analog circuitry. If the AD9981 is interfacing with lower voltage

logic, VDD may be connected to a lower supply voltage (as low as 1.8 V) for compatibility.

PVD (1.8 V)

Clock Generator Power Supply.

The most sensitive portion of the AD9981 is the clock generation circuitry. These pins provide power to the clock PLL

and help the user design for optimal performance. The designer should provide quiet, noise-free power to these pins.

DAVDD (1.8 V)

Digital Input Power Supply. This supplies power to the digital logic.

GND

Ground.

The ground return for all circuitry on-chip. It is recommended that the AD9981 be assembled on a single solid ground

plane, with careful attention to ground current paths.

AD9981/PCB Datasheet(PDF) 10 Page - Analog Devices