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

The DACx311 offers single-supply operation, and is often used in close proximity to digital logic, microcontrollers, microprocessors, and digital signal processors. The more digital logic present in the design and the higher the switching speed, the more difficult the task is to achieve good performance from the converter.

As a result of the single ground pin of the DACx311, all return currents, including digital and analog return currents, must flow through the GND pin. Ideally, GND is connected directly to an analog ground plane. Separate this plane from the ground connection for the digital components until connected at the power entry point of the system.

The power applied to AV_DD must be well-regulated 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 the internal logic switches state. This noise can easily couple into the DAC output voltage through various paths between the power connections and analog output. This condition is particularly true for the DACx311, as the power supply is also the reference voltage for the DAC.

As with the GND connection, connect AV_DD to a 5‑V power supply plane or trace that is separate from the connection for digital logic until connected at the power entry point. In addition, 1-μF to 10-μF and 0.1-μF bypass capacitors are strongly recommended. In some situations, additional bypassing can be required, such as a 100 μF electrolytic capacitor or even a Pi filter made up of inductors and capacitors—all designed to essentially low-pass filter the 5-V supply and remove high-frequency noise.