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Application Section
(Continued)
Symmetry between the positive and negative paths in the
layout of differential circuitry should be maintained to mini-
mize the imbalance of amplitude and phase of the differential
signal.
These free evaluation boards are shipped when a device
sample request is placed with National Semiconductor.
Component value selection is another important parameter
in working with high speed/high performance amplifiers.
Choosing external resistors that are large in value compared
to the value of other critical components will affect the closed
loop behavior of the stage because of the interaction of
these resistors with parasitic capacitances. These parasitic
capacitors could either be inherent to the device or be a
by-product of the board layout and component placement.
Moreover, a large resistor will also add more thermal noise to
the signal path. Either way, keeping the resistor values low
will diminish this interaction. On the other hand, choosing
very low value resistors could load down nodes and will
contribute to higher overall power dissipation and high dis-
tortion.
Device
Package
Evaluation Board Part
Number
LMH6624MF
SOT23–5
CLC730216
LMH6624MA
SOIC-8
CLC730227
LMH6624
www.national.com
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