or
maximum
values. For the
IAM-91563, these parameters are:
Conversion Gain (G
test
), Noise
Figure (NF
test
), and Device
Current (I
d
). Each of these
guaranteed parameters is 100%
tested.
Values for most of the parameters
in the table of Electrical Specifica-
tions that are described by
typical
data are the mathematical mean
(µ), of the normal distribution
taken from the characterization
data. For parameters where
measurements or mathematical
averaging may not be practical,
such as the Typical Reflection
Coefficients table or performance
curves, the data represents a
nominal part taken from the
“center” of the characterization
distribution. Typical values are
intended to be used as a basis for
electrical design.
To assist designers in optimizing
not only the immediate circuit
using the IAM-91563, but to also
optimize and evaluate trade-offs
that affect a complete wireless
system, the
standard deviation
(σ) is provided for many of the
Electrical Specifications param-
eters (at 25°) in addition to the
mean. The standard deviation is a
measure of the variability about
the mean. It will be recalled that a
normal distribution is completely
described by the mean and
standard deviation.
Standard statistics tables or
calculations provide the probabil-
ity of a parameter falling between
any two values, usually symmetri-
cally located about the mean.
Referring to Figure 12 for ex-
ample, the probability of a param-
eter being between
±
1σ is 68.3%;
between
±
2σ is 95.4%; and be-
tween
±
3σ is 99.7%.
68%
use multiple vias to further
minimize ground path inductance.
95%
99%
-3σ
-2σ
-1σ Mean (µ) +1σ +2σ
(typical)
Parameter Value
+3σ
C
Figure 19. Normal Distribution.
Phase Reference Planes
The positions of the reference
planes used to specify Reflection
Coefficients for this device are
shown in Figure 20. As seen in the
illustration, the reference planes
are located at the point where the
package leads contact the test
circuit.
REFERENCE
PLANES
R
Figure21. RFLayout.
TEST CIRCUIT
It is recommended that the PCB
pads for the ground pins
not
be
connected together underneath
the body of the package. PCB
traces hidden under the package
cannot be adequately inspected
for SMT solder quality.
Figure20. PhaseReferencePlanes.
PCB Material
FR-4 or G-10 printed circuit board
materials are a good choice for
most low cost wireless applica-
tions. Typical board thickness is
0.020 to 0.031 inches. Thicknesses
greater than 0.031 inch began to
introduce excessive inductance in
the ground vias. The width of the
50
Ω
microstriplines on PC boards
in this thickness range is also very
convenient for mounting chip
components such as the series
inductor at the input or DC
blocking and bypass capacitors.
For applications using higher
frequencies such as the 5.8 GHz
ISM band, the additional cost of
PTFE/glass dielectric materials
may be warranted to minimize
transmission line loss at the
mixer’s RF input. An additional
consideration of using lower cost
RF Layout
An RF layout similar to the one in
Figure 21 is suggested as a
starting point for microstripline
designs using the IAM-91563
mixer. This layout shows the
capacitor for the Source Bypass
pin and the optional resistor used
to increase bias current. Adequate
grounding is important to obtain
maximum performance and to
maintain stability. Both of the
ground pins of the MMIC should
be connected to the RF
groundplane on the backside of
the PCB by means of plated
through holes (vias) that are
placed near the package termi-
nals. As a minimum, one via
should be located next to each of
the ground pins to ensure good RF
grounding. It is a good practice to
7-141
AGILENT [ AGILENT TECHNOLOGIES, LTD. ]
