10 Power Supply Recommendations

The DACx1416 require five power supply inputs: VIO, VDD, VAA, VCC and VSS. VDD and VAA should be at same level. Assuming VIO and VDD/VAA to be different, there are four separate power-supply sources required.

Place a 0.1-µF ceramic capacitor close to each power-supply pin. Be aware that VCC and VSS have two pins each. In addition, a 4.7-µF or 10-µF bulk capacitor is recommended for each power supply; tantalum or aluminum types can be chosen for the bulk capacitors.

There is no sequencing requirement for the power supplies. As the DAC output range is configurable, make sure that the power-supplies have enough headroom to achieve linearity at codes close to the power supply rails. When sourcing or sinking current from or to the DAC output, the heat dissipation must be considered. For example, a typical application of MZM bias with 25-mA load current from or to 12 channels with 2.5-V power-supply headroom can create a power dissipation across the DAC of (12 × 2.5 × 25 mA) = 0.75 W. The thermal design to dissipate the power in this example may involve inclusion of heat sinks in order to avoid thermal shutdown of the device.