7

PCB precautions

•

A ground plane on each layer of the PCB with multiple vias dedicated for interconnexion is recommended

for high-speed circuit applications to provide low parasitic inductance and resistance. The goal is to have a

“common ground plane” where AGND and DGND are connected with the lowest DC resistance and lowest

AC impedance.

•

The separation of the analog signal from the digital output is mandatory to prevent noise from coupling onto

the input signal.

•

Power supply bypass capacitors must be placed as close as possible to the IC pins to improve high-

frequency bypassing and reduce harmonic distortion.

•

All leads must be as short as possible, especially for the analog input, so to decrease parasitic capacitance

and inductance.

•

To minimize the transition current when the output changes, the capacitive load at the digital outputs must

be reduced as much as possible by using the shortest possible routing tracks. One way to reduce capacitive

load is to remove the ground plane under the output digital pins and layers at high sampling frequencies.

•

Choose the smallest possible component sizes (SMD).

LEOAD128

PCB precautions

DS13668 - Rev 2

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