DAC8541

SLAS353 − DECEMBER 2001

19

www.ti.com

APPLICATION INFORMATION

layout

A precision analog component requires careful layout, adequate bypassing, and clean, well-regulated power

supplies. The following measures should be taken to assure optimum performance of the DAC8541.

The DAC8541 offers dual-supply operation, as it can often be used in close proximity with digital logic,

microcontrollers, microprocessors, and digital signal processors. The more digital logic present in the design

and the higher the switching speed, the more important it becomes to separate the analog and digital ground

and supply planes at the DAC.

Because the DAC8541 has both analog and digital ground pins, return currents can be better controlled and

have less effect on the DAC’s output error. Ideally, AGND would be connected directly to an analog ground plane

and DGND to the digital ground plane. The analog ground plane would be separate from the ground connection

for the digital components until they were connected at the power entry point of the system.

and low-noise. Switching power supplies and dc/dc converters often have high-frequency glitches or spikes

riding on the output voltage. In addition, digital components can create similar high-frequency spikes as their

internal logic switches states. This noise can easily couple into the DAC output voltage through various paths

between the power connections and analog output.

from the connection for digital logic until they are connected at the power entry point. In addition, the 1-

µF to

10-

µF and 0.1-µF bypass capacitors are strongly recommended. In some situations, additional bypassing may

be required, such as a 100-

µF electrolytic capacitor or even a Pi filter made up of inductors and capacitors—all