AD8003

Data Sheet

Rev. C | Page 14 of 16

Minimizing the trace length and widening the trace from the

capacitors to the amplifier reduces the trace inductance. A

series inductance with the parallel capacitance can form a tank

circuit, which can introduce high frequency ringing at the output.

This additional inductance can also contribute to increased

distortion due to high frequency compression at the output.

The use of vias should be minimized in the direct path to the

amplifier power supply pins because vias can introduce parasitic

inductance, which can lead to instability. When required, use

multiple large diameter vias because this lowers the equivalent

parasitic inductance.

GROUNDING

The use of ground and power planes is encouraged as a method

of proving low impedance returns for power supply and signal

currents. Ground and power planes can also help to reduce stray

trace inductance and provide a low thermal path for the amplifier.

Ground and power planes should not be used under any of the

pins of the AD8003. The mounting pads and the ground or power

planes can form a parasitic capacitance at the amplifiers input.

Stray capacitance on the inverting input and the feedback

resistor form a pole, which degrades the phase margin, leading

to instability. Excessive stray capacitance on the output also forms a

pole, which degrades phase margin.