There are several critical signals which require specific care during board design:
- Analog input and clock signals
- Traces should be as short as possible and vias should be avoided where possible to minimize impedance discontinuities.
- Traces should be routed using loosely coupled 100-Ω differential traces.
- Differential trace lengths should be matched as close as possible to minimize phase imbalance and HD2 degradation.
- Digital output interface
- Traces should be routed using tightly coupled 100-Ω differential traces.
- Voltage reference
- The bypass capacitor should be placed as close to the device pins as possible and connected between VREF and REFGND – on top layer avoiding vias.
- Depending on configuration an additional bypass capacitor between REFBUF and REFGND may be recommended and should also be placed as close to pins as possible on top layer.
- Power and ground connections
- Provide low resistance connection paths to all power and ground pins.
- Use power and ground planes instead of traces.
- Avoid narrow, isolated paths which increase the connection resistance.
- Use a signal/ground/power circuit board stackup to maximize coupling between the ground and power plane.