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Figure 1: Characteristic gain performance for Mini-Circuits PGA-
103+ high-dynamic-range MMIC amplifier.
Figure 2: Yoni2 Search for a surface mount amplifier with 13 dB minimum gain from 50 to 1000 MHz
information is widely available on
product datasheets and supplier
websites, and most parametric search
engines for RF components match
customer performance criteria against
these figures.
The problem with this approach is
that in reality, electrical performance
is not a single value but a variable
dependent on frequency. For products
specified over a wide frequency range,
the spec may understate or overstate
performance within a particularbandto
better approximate performance over
the product’s full rated frequency
range. If the customer only intends to
use the product within a specificband,
searching by performance specs
alonemay reject a part that actually
provides ideal performance for the
customer’s intended application –
or worse, it may include a part that
achieves marginal performance relative
to the requirement.
For example, a published spec table
shows 11 dB typical gain for Mini-
Circuits’ PGA-103+ high-dynamic-range
MMIC amplifier, which is specified from
50 to 4000 MHz. In reality, the model’s
gain curve exhibits a negative slope
when plotted over frequency as shown
in figure 1.
Notice that characteristic gain
performance is greater than the 11
dB spec up to 1500 MHz. Therefore
a customer working in an application
at lower frequencies with a 13 dB
minimum gain requirement may falsely
dismiss this model as a viable option if
he bases his search onthe spec alone.
Specs may offer a convenient general
point of reference, but they are, by
nature, reductive. Nevertheless, this is
the methodology most RF component
search engines employ. Such search
engines may still be preferable to
manually poring over dozens of
datasheets, tables, and charts, but
they should be approached with
healthy skepticism toward the accuracy
and completeness of the results they
return.
New-Tech Magazine Europe l 29