Datasheet

DAC7568

DAC8168

DAC8568

SBAS430D –JANUARY 2009–REVISED MAY 2012

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LAYOUT The power applied to AV

should be well-regulated

and low noise. Switching power supplies and dc/dc

A precision analog component requires careful layout,

converters often have high-frequency glitches or

adequate bypassing, and clean, well-regulated power

spikes riding on the output voltage. In addition, digital

supplies.

components can create similar high-frequency spikes

as their internal logic switches states. This noise can

The DAC7568, DAC8168, and DAC8568 offer single-

easily couple into the DAC output voltage through

supply operation, and are often used in close

various paths between the power connections and

proximity with digital logic, microcontrollers,

analog output.

microprocessors, and digital signal processors. The

more digital logic present in the design and the higher

As with the GND connection, AV

should be

the switching speed, the more difficult it is to keep

connected to a power-supply plane or trace that is

digital noise from appearing at the output.

separate from the connection for digital logic until

they are connected at the power-entry point. In

As a result of the single ground pin of the DAC7568,

addition, a 1μF to 10μF capacitor and 0.1μF bypass

DAC8168, and DAC8568, all return currents

capacitor are strongly recommended. In some

(including digital and analog return currents for the

situations, additional bypassing may be required,

DAC) must flow through a single point. Ideally, GND

such as a 100μF electrolytic capacitor or even a Pi

would be connected directly to an analog ground

filter made up of inductors and capacitors—all

plane. This plane would be separate from the ground

designed to essentially low-pass filter the supply and

connection for the digital components until they were

remove the high-frequency noise.

connected at the power-entry point of the system.

Product Folder Link(s): DAC7568 DAC8168 DAC8568