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FN6142.4

March 15, 2007

Power Supply Bypassing Printed Circuit Board

Layout

As with any modern operational amplifier, a good printed

circuit board layout is necessary for optimum performance.

Lead lengths should be as short as possible. The power

supply pin must be well bypassed to reduce the risk of

oscillation. For normal single supply operation, where the

tantalum capacitor in parallel with a 0.1µF ceramic capacitor

combination should be placed at each supply pin to ground if

becomes the negative supply rail.

Printed Circuit Board Layout

For good AC performance, parasitic capacitance should be

kept to minimum. Use of wire wound resistors should be

avoided because of their additional series inductance. Use

of sockets should also be avoided if possible. Sockets add

parasitic inductance and capacitance that can result in

compromised performance. Minimizing parasitic capacitance

at the amplifier's inverting input pin is very important. The

feedback resistor should be placed very close to the

inverting input pin. Strip line design techniques are

recommended for the signal traces.

ISL59112