10

FN6247.3

April 13, 2007

Power Supply Bypassing and Printed Circuit

Board Layout

As with any high frequency device, good printed circuit

board layout is necessary for optimum performance. Low

impedance ground plane construction is essential. Surface

mount components are recommended, but if leaded

components are used, lead lengths should be as short as

possible. The power supply pins must be well bypassed to

reduce the risk of oscillation. The combination of a 4.7µF

tantalum capacitor in parallel with a 0.01µF capacitor has

been shown to work well when placed at each supply pin.

For good AC performance, parasitic capacitance should be

kept to a minimum, especially at the inverting input. When

ground plane construction is used, it should be removed

from the area near the inverting input to minimize any stray

capacitance at that node. Carbon or Metal-Film resistors are

acceptable with the Metal-Film resistors giving slightly less

peaking and bandwidth because of additional series

inductance. Use of sockets, particularly for the SO package,

should be avoided if possible. Sockets add parasitic

inductance and capacitance which will result in additional

peaking and overshoot.

ISL28190, ISL28290