Datasheet

DAC5311

DAC6311

DAC7311

SBAS442B –AUGUST 2008–REVISED MAY 2013

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LAYOUT

A precision analog component requires careful layout, The power applied to AV

should be well-regulated

adequate bypassing, and clean, well-regulated power and low-noise. Switching power supplies and dc/dc

supplies. converters often have high-frequency glitches or

spikes riding on the output voltage. In addition, digital

The DACx311 offers single-supply operation; it is

components can create similar high-frequency spikes

often used in close proximity with digital logic,

as the internal logic switches state. This noise can

microcontrollers, microprocessors, and digital signal

easily couple into the DAC output voltage through

processors. The more digital logic present in the

various paths between the power connections and

design and the higher the switching speed, the more

analog output. This condition is particularly true for

difficult it is to achieve good performance from the

the DACx311, as the power supply is also the

converter.

reference voltage for the DAC.

Because of the single ground pin of the DACx311, all

As with the GND connection, AV

should be

return currents, including digital and analog return

connected to a +5V power supply plane or trace that

currents, must flow through the GND pin. Ideally,

is separate from the connection for digital logic until

GND is connected directly to an analog ground plane.

they are connected at the power entry point. In

This plane should be separate from the ground

addition, the 1μF to 10μF and 0.1μF bypass

connection for the digital components until they are

capacitors are strongly recommended. In some

connected at the power entry point of the system.

situations, additional bypassing may be required,

such as a 100μF electrolytic capacitor or even a Pi

filter made up of inductors and capacitors—all

designed to essentially low-pass filter the +5V supply,

removing the high-frequency noise.

Product Folder Links: DAC5311 DAC6311 DAC7311