HP IAM-91563-BLK 0.8-6 ghz 3v downconverter Datasheet

0.8 – 6 GHz 3 V Downconverter
Technical Data
IAM-91563
Features
• +0 dBm Input IP3 at 1.9 GHz
Surface Mount Package
SOT-363 (SC-70)
• Single +3V Supply
• 8.5 dB SSB Noise Figure at
1.9 GHz
• 9.0 dB Conversion Gain at
1.9 GHz
• Ultra-miniature Package
Applications
6 IF and Vd
LO 1
91
• Downconverter for PCS,
PHS, ISM, WLL, and other
Wireless Applications
Pin Connections and
Package Marking
GND 2
RF 3
5 GND
4 SOURCE
BYPASS
Note:
1. Package marking provides orientation and identification.
Simplified Schematic
IF and Vd
6
LO
1
SOURCE
BYPASS
RF
4
3
GROUND
2, 5
7-135
Description
Hewlett-Packard’s IAM-91563 is an
economical 3V GaAs MMIC mixer
used for frequency down-conversion. RF frequency coverage is
from 0.8 to 6 GHz and IF coverage
is from 50 to 700 MHz. Packaged
in the SOT-363 package, this
4.0␣ sq. mm. package requires half
the board space of a SOT-143 and
only 15% the board space of an
SO-8 package.
At 1.9 GHz, the IAM-91563 provides 9 dB of conversion gain,
thus eliminating an RF or IF gain
stage normally needed with a
lossy mixer. LO drive power is
nominally only -5 dBm, eliminating an LO buffer amplifier. The
8.5 dB noise figure is low enough
to allow the system to use a low
cost LNA. The -6 dBm Input IP3
provides adequate system linearity
for most commercial applications,
but is adjustable to 0 dBm.
The circuit uses GaAs PHEMT
technology with proven reliability,
and uniformity. The MMIC
consists of a cascode FET structure that provides unbalanced gm
modulation type mixing. An onchip LO buffer amp drives the
mixer while bias circuitry allows a
single +3V supply (through a
choked IF port). The LO port is
internally matched to 50 Ω. The
RF and IF ports are high impedance and require external matching networks.
5965-9973E
IAM-91563 Absolute Maximum Ratings
Symbol
Parameter
Absolute
Units Maximum[1]
Vd
VRF, VLO
Pin
Tch
TSTG
Device Voltage, RF output to ground
RF voltage or LO voltage to ground
CW RF Input Power
Channel Temperature
Storage Temperature
V
V
dBm
°C
°C
6.0
+0.5, -1.0
+13
150
-65 to 150
Thermal Resistance[2]:
θch-c = 310°C/W
Notes:
1. Permanent damage may occur if
any of these limits are exceeded.
2. TC = 25°C (TC is defined to be the
temperature at the package pins
where contact is made to the
circuit board).
IAM-91563 Electrical Specifications, TC = 25°C, Vd = 3 V
Symbol
G test
Parameters and Test Conditions
Gain in test circuit[1]
circuit[1]
Units Min. Typ. Max. Std Dev[2]
RF=1890 GHz, IF=250 MHz
dB
RF=1890 GHz, IF=250 MHz
dB
NFtest
Noise Figure in test
Id
Device Current
NF
Noise Figure (RF & IF with external matching,
IF=250 MHz, LO power=-5 dBm)
f = 0.9 GHz
f = 1.9 GHz
f = 2.4 GHz
f = 4.0 GHz
f = 6.0 GHz
dB
Conversion gain (RF and IF with external matching,
IF=250 MHz, LO power=-5 dBm)
f = 0.9 GHz
f = 1.9 GHz
f = 2.4 GHz
f = 4.0 GHz
f = 6.0 GHz
dB
Output power @ 1 dB compression (RF and IF with
external matching, IF=250 MHz, LO power =-5 dBm)
f = 0.9 GHz
f = 1.9 GHz
f = 2.4 GHz
f = 4.0 GHz
f = 6.0 GHz
dBm
Gc
P1 dB
mA
4.0
6.0
9.0
8.5
11.0
9.0
12.0
7.0
8.5
11.0
16.5
18.0
11.0
9.0
7.7
4.6
1.7
-6.7
-8.0
-8.7
-15.0
-17.8
0.5
1.5
1.3
RL RF
RF port return loss
f = 0.5 - 6.0 GHz
dB
-1.7
0.2
RL LO
LO port return loss
f = 0.5 - 6.0 GHz
dB
-9.4
0.3
RL IF
IF port return loss
f = 50 - 700 MHz
dB
-3.7
0.2
IP3
Input Third Order Intercept Point
Id = 9.0 mA, LO power = -5 dBm
RF = 1.9 GHz, IF = 250 MHz
dBm
-6.0
1.3
IP3
Input Third Order Intercept Point
Id = 15 mA, LO power = -2 dBm
RF = 1.9 GHz, IF = 250 MHz
dBm
0
1.1
dB
18
ISOLR-I RF-IF Isolation (No Match)
dB
2
ISOLL-I LO-IF Isolation (No Match)
dB
4
ISOLL-R LO-RF Isolation
RF = 1.9 GHz
Notes:
1. Guaranteed specifications are 100% tested in the circuit in Figure 18 in the Applications Information section.
2. Standard deviation number is based on measurement of at least 500 parts from three non-consecutive wafer lots during
the initial characterization of this product, and is intended to be used as an estimate for distribution of the typical
specification.
7-136
IAM-91563 Typical Performance, TC = 25°C, Vd = 3.0 V, RF=1890 MHz, LO = -5 dBm, IF = 250 MHz,
unless otherwise stated.
7-137
IAM-91563 Typical Performance, TC = 25°C, Vd = 3.0 V, RF=1890 MHz, LO = -5 dBm, IF = 250 MHz,
12
12
10
10
10
8
6
TA = +85°C
TA = +25°C
TA = -40°C
4
2
8
6
TA = 3.3V
TA = 3.0V
TA = 2.7V
4
2
100
200 300 400
500 600 700
0
100
200 300 400
IF FREQUENCY (MHz)
8
6
TA = +85°C
TA = +25°C
TA = -40°C
4
2
0
500 600 700
100
Figure 10. SSB Noise Figure vs.
Frequency and Temperature.
Figure 11. Conversion Gain vs.
Frequency and Supply Voltage.
14
P1 dB and INPUT IP3 (dBm)
NF
12
10
8
GAIN
6
500 600 700
Figure 12. Conversion Gain vs.
Frequency and Temperature.
0
0
-2
-2
-4
IP3
-4
-6
P1 dB
-8
200 300 400
IF FREQUENCY (MHz)
IF FREQUENCY (MHz)
ISOLATION (dB, No Match)
0
CONVERSION GAIN and
NOISE FIGURE (dB)
CONVERSION GAIN (dB)
12
CONVERSION GAIN (dB)
SSB NOISE FIGURE (dB)
unless otherwise stated.
RF-IF
LO-IF
-6
-8
LO-RF
-10
-12
-14
-16
-18
4
-10
-9
-8
-7
-6
-5 -4
-3
-2
-1
LO POWER (dBm)
-10
-10
-20
-9
-8
-7
-6
RF-LO
ISOLATION (dB)
-8
-12
-16
-20
RF-IF
-28
-32
LO-IF
-36
-40
0
1
2
3
4
-2
-1
Figure 14. One dB Compression and
Input Third Order Intercept vs. LO
Drive Power.
0
-24
-3
LO POWER (dBm)
Figure 13. Available Conversion Gain
and Noise Figure vs. LO Drive Power.
-4
-5 -4
5
6
RF FREQUENCY (GHz)
Figure 16. Isolation (RF-LO, RF-IF,
LO-IF) vs. Frequency with RF and IF
Matching Networks.
7-138
0
1
2
3
4
5
6
RF FREQUENCY (GHz)
Figure 15. Isolation (LO-RF, RF-IF,
LO-IF) vs. Frequency with no RF and
IF Matching Networks.
IAM-91563 Typical Reflection Coefficients, TC = 25°C, Z O = 50 Ω, Vd = 3 V
Frequency (GHz)
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3
3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
4
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
5
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.8
5.9
6
RF (Mag)
0.91
0.91
0.91
0.92
0.91
0.88
0.87
0.85
0.84
0.83
0.82
0.82
0.81
0.81
0.81
0.81
0.81
0.80
0.80
0.81
0.81
0.81
0.82
0.83
0.83
0.83
0.85
0.86
0.87
0.85
0.83
0.83
0.82
0.83
0.83
0.84
0.84
0.84
0.85
0.84
0.85
0.85
0.85
0.86
0.85
0.84
0.84
0.84
0.83
0.83
0.81
0.81
0.80
RF (Ang)
-18
-21
-23
-25
-28
-29
-32
-33
-34
-35
-37
-37
-39
-40
-41
-42
-44
-45
-45
-46
-48
-50
-51
-53
-55
-56
-59
-61
-64
-67
-71
-71
-73
-76
-79
-82
-85
-87
-91
-95
-97
-100
-103
-106
-108
-113
-115
-117
-121
-123
-125
-128
-130
LO (Mag)
LO (Ang)
IF (Mag)
IF (Ang)
0.43
0.39
0.39
0.39
0.39
0.39
0.40
0.39
0.39
0.38
0.39
0.39
0.40
0.39
0.39
0.39
0.39
0.39
0.38
0.39
0.38
0.38
0.37
0.37
0.36
0.36
0.35
0.35
0.34
0.34
0.33
0.33
0.32
0.32
0.31
0.32
0.31
0.30
0.30
0.29
0.29
0.28
0.29
0.27
0.28
0.26
0.28
0.25
0.27
0.25
0.27
0.25
0.27
0.25
0.27
0.25
0.27
0.25
0.26
0.24
-1
-6
-8
-9
-10
-11
-14
-14
-16
-17
-17
-19
-22
-22
-24
-25
-26
-27
-29
-29
-31
-31
-32
-33
-34
-35
-36
-36
-37
-37
-38
-39
-39
-40
-40
-42
-42
-45
-43
-46
-45
-47
-48
-49
-50
-51
-52
-52
-54
-54
-57
-56
-58
-58
-61
-61
-64
-65
-67
-65
0.64
0.63
0.63
0.63
0.62
0.62
0.62
-8
-9
-10
-10
-11
-12
-13
7-139
Introduction
The IAM-91563 is a miniature
downconverter developed for use
in superheterodyne receivers for
commercial wireless applications
with RF bands from 800 MHz to
6␣ GHz. Operating from only
3␣ volts, the IAM-91563 is an
excellent choice for use in low
current applications such as:
1.9␣ GHz Personal Communication
Systems (PCS) & Personal Handy
System (PHS), 2 GHz Digital
European Cordless Telephone
(DECT), and 800 MHz cellular
telephones (e.g., GSM, NADC,
JDC). Combined with HewlettPackard’s other RFICs and discrete components housed in the
same ultra-miniature SOT-363
package, the IAM-91563 also
provides flexible, building-block
solutions for WLAN’s and wireless
datacomm such as PCMCIA RF
modems as well as many Industrial, Scientific and Medical (ISM)
systems operating at 900␣ MHz,
2.5␣ GHz, and 5.8 GHz.
The IAM-91563 is a 3-port,
downconverting RFIC mixer of the
cascode (common source common gate) type that uses a low
level (-5 dBm) local oscillator (LO)
to convert an RF signal in the
800␣ MHz to 6 GHz range to an IF
between 50 and 700 MHz. The
basic mixing function takes place
in a cascode connected pair of
FETs as shown in Figure 17.
IF
LO
FET 2
RF
FET 1
Figure17. CascodeFETMixer.
The received RF signal is connected to the gate of FET1 and the
LO is applied to the gate of FET2.
The purpose of FET2 is to vary the
transconductance of FET1 over a
highly nonlinear region at the rate
of the LO frequency. This produces the nonlinearity required
for frequency mixing to take
place. This type of mixer is also
known as a “transconductance
mixer.” The IF is taken from the
drain of FET2.
An advantage of the cascode type
of design is the inherent isolation
between the gates of the two
FETs which results in very good
LO-to-RF isolation. An integrated
buffer amplifier between the LO
input and the gate of FET2 not
only increases the LO-RF isolation
but also reduces the amount of LO
input power required by the
mixer.
The IAM-91563 uses an innovative
bias regulation circuit that realizes
several benefits to the designer.
First, the IAM-91563 operates with
a single, positive device voltage
from 1.5 to 5 volts with stable
performance over a wide temperature range. Second, a unique
feature of the IAM-91563 allows
the device current to be easily
increased by adding an external
resistor to boost device current
and increase linearity.
Using a minimum of external
components with a standard bias
of 3 volts/9 mA and LO power of
-5␣ dBm, the IAM-91563 mixer
achieves an RF to IF conversion
gain of 9 dB at 1.9 GHz with a
noise figure of 8.5 dB and an input
third order intercept point of
-6␣ dBm. LO-to-IF isolation is
greater than 35 dB. Setting the
bias for the higher linearity/higher
current mode (approximately
16␣ mA) along with an LO drive
7-140
level of -2 dBm will boost the
input IP3 to approximately 0 dBm.
Test Circuit
The circuit shown in Figure 18 is
used for 100% RF and DC testing.
The test circuit is impedance
matched for an RF of 1890 MHz
and an IF of 250 MHz. The LO is
set at 1640 MHz and -5 dBm for
low side conversion. (High side
conversion with an LO of
2240␣ MHz would produce similar
performance.) The RF choke at
the IF port is used to provide DC
bias. Tests in this circuit are used
to guarantee the Gtest, NFtest, and
Device Current (Id) parameters
shown in the table of Electrical
Specifications.
0.5 pF
Vd
220 nH
100 pF
(2)
Z = 50
500 pF 68 nH
IF
250 MHz
Z = 110
I=10.4 mm
91
IAM-91563 Applications
Information
RF
1890 MHz
Z = 50
4.7 pF
LO
1640 MHz
Figure 18. Test Circuit.
Specifications and
Statistical Parameters
Several categories of parameters
appear within this data sheet.
Parameters may be described with
values that are either “minimum
or maximum,” “typical,” or
“standard deviations.”
The values for parameters are
based on comprehensive product
characterization data, in which
automated measurements are
made on of a minimum of
500␣ parts taken from 3 nonconsecutive process lots of
semiconductor wafers. The data
derived from product characterization tends to be normally
distributed, e.g., fits the standard
“bell curve.”
Parameters considered to be the
most important to system performance are bounded by minimum
or maximum values. For the
IAM-91563, these parameters are:
Conversion Gain (Gtest), Noise
Figure (NFtest), and Device
Current (Id). Each of these
guaranteed parameters is 100%
tested.
Values for most of the parameters
in the table of Electrical Specifications 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 parameters (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 probability of a parameter falling between
any two values, usually symmetrically located about the mean.
Referring to Figure 12 for example, the probability of a parameter being between ± 1σ is 68.3%;
between ± 2σ is 95.4%; and between ± 3σ is 99.7%.
use multiple vias to further
minimize ground path inductance.
68%
95%
99%
-3σ
-2σ
-1σ Mean (µ) +1σ +2σ
(typical)
+3σ
Parameter Value
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
TEST CIRCUIT
Figure20. PhaseReferencePlanes.
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 terminals. 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
R
Figure21. RFLayout.
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.
PCB Material
FR-4 or G-10 printed circuit board
materials are a good choice for
most low cost wireless applications. 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
materials at higher frequencies is
the degradation in the Q’s of
transmission lines used for
impedance matching.
Biasing
The IAM-91563 is a voltage-biased
device and is designed to operate
in the “normal mode” from a
single, +3 volt power supply with
a typical current drain of only
9␣ mA. The internal current regulation circuit allows the mixer to be
operated with voltages as high as
+5␣ volts or as low as +1.5 volt.
The device current can be increased up to 20 mA by adding an
external resistor from the Source
Bypass pin to ground. This feature
makes it possible to operate the
IAM-91563 in the “high power
mode” to achieve greater linearity.
Refer to the section titled “High
Linearity Mode” for information
on applications and performance
when using this feature.
Application Guidelines
Several design considerations
should be taken into account to
ensure that maximum performance is obtained from the
IAM-91563 downconverter. The
RF and IF ports must be impedance matched at their respective
frequencies to the circuits to
which they are connected. This is
typically 50 ohms when the mixer
is used as a building block component in a 50-ohm system. These
ports have been left untuned on
the MMIC to allow the mixer to be
used over a wide range of RF and
IF bands. The LO port is already
sufficiently well matched (less
than 1 dB of mismatch loss) for
most applications.
As with most mixers, appropriate
filters must be placed at the RF
port and IF port such as in
Figure␣ 22. The filter in front of the
RF port eliminates interference
from the image frequency and the
IF filter prevents RF and LO signal
leakage into the IF signal processing circuitry.
RF
HP Filter
IF
LP Filter
LO
Figure 22. Image and IF Filters.
Additional design considerations
relate to the use of higher bias
current where greater linearity is
required, bypassing of the Source
Bypass pin, bias injection, and DC
blocking and bypassing.
Each of these design factors will
be discussed in greater detail in
the following sections.
RF Port
A well matched RF port is especially important to maximize the
conversion gain of the IAM-91563
mixer. Matching is also necessary
to realize the specified noise
figure and RF-to-LO isolation. The
amount the conversion gain can
be increased by impedance
matching is equal to the mismatch
loss at the RF port. The impedance of the RF port is characterized by the measured reflection
coefficients shown in Typical
Reflection Coefficients Table. The
maximum “mismatch gain” that
results from eliminating the
mismatch loss is expressed in dB
as a function of the reflection
coefficient as:
GRF, mm = 10 log10
1
1 – ΓRF
2
(1)
For wireless bands in the 800 MHz
to 6 GHz range, the magnitude of
the reflection coefficient of the RF
port varies from 0.91 to 0.80,
which corresponds to a mismatch
gain of 7.6 to 4.4 dB.
7-142
The impedance of the RF port is
capacitive, and for frequencies
from 800 MHz to 2.4 GHz, falls
very near the R=1 circle of a Smith
chart. While these impedances
could be easily matched to
50␣ ohms with a simple series
inductor, it is advantageous to use
a 2-element matching network of
the series C, shunt L type as
shown in Figure 23 instead. There
are two main reasons for this
choice. The first is to incorporate
a high pass filter characteristic
into the matching circuit. Second,
the series C, shunt L combination
will match the entire range of RF
port impedances to 50 Ω. Most
wireless communication bands
are sufficiently narrow that a
single (mid-band) frequency
approach to impedance matching
is adequate.
RF
Input
C
RF
L
IF
LO
Figure 23. RF Input HPF Matching.
Impedance matching can be
accomplished with lumped
element components, transmission lines, or a combination of
both. The use of surface mount
inductors and capacitors is
convenient for lower frequencies
to minimize printed circuit board
space. The use of high impedance
transmission lines works well for
higher frequencies where lumped
element inductors may have
excessive parasitics and/or selfresonances.
If other types of matching networks are used, it should be noted
that while the RF input terminal of
the IAM-91563 is at ground
potential, it should not be used as
a current sink. If the input is
The IF port impedance matching
network should be of the low pass
filter type to reflect RF and LO
power back into the mixer while
allowing the IF to pass through.
The shunt C, series L type of
network in Figure 24 is a very
practical choice that will meet the
low pass filter requirement while
matching any IF impedances over
the 50 - 700 MHz range to 50 ohms.
IF
LO
RFC
RF
IF
IF
Output
LO
The IAM-91563 can be used for
downconvesion to intermediate
frequencies in the 50 to 700 MHz
range. Similar to the RF port, the
reflection coefficient at the IF is
fairly high and Equation 1 can be
used to predict a mismatch gain of
up to 2.2 dB by impedance matching. A well matched IF port will
also provide the optimum output
power and LO-to-IF isolation.
Reflection coefficients for the IF
port are shown in the Typical
Reflection Coefficients Table.
RF
Vd
IF
Output
Figure 24. IF Output LPF Matching.
The DC bias is also applied to the
mixer through the IF port. Figure
25 shows how an inductor (RFC)
is used to isolate the IF from the
DC supply. The bias line is bypassed to ground with a capacitor
to keep RF off of the DC supply
lines and to prevent dips or peaks
in the response of the mixer.
9 mA to as high as 20 mA. The
additional current increases mixer
linearity (IP3) and output
power(P1dB). Mixer performance
at higher device current is shown
in Figures 26 and 27.
14
Figure 25. Bias Connection.
LO Port
The LO input port is internally
matched to 50 Ω within a 2.2:1
VSWR over the entire operating
frequency range. Additional
matching will normally not be
needed. However, if desired, a
small series inductor can be used
to provide some improvement in
the LO match and thus reduce the
LO drive level requirement by up
to 0.7 dB. Reflection coefficients
for the LO port are shown in the
table of Typical Reflection
Coefficients.
CONVERSION GAIN and NF (dB)
IF port
Bypass
Capacitor
NF
12
10
GAIN
8
6
4
7
9
11
13
15
17
19
DEVICE CURRENT (mA)
1000
56
21
9
5
3
Approximate Resistor Value (Ω)
Figure 26. Available Conversion Gain
Figure 26. Available Conversion Gain
and SSB Noise Figure vs. Device
Current (Source Resistor).
0
Source Bypass Pin
The Source Bypass pin should be
RF bypassed to ground at both the
RF and LO frequencies as well as
the IF. Many capacitors with
values large enough to adequately
bypass lower intermediate frequencies contain parasitics that
may have resonances in the RF
band. It is often practical to use
two capacitors in parallel for this
purpose instead of one. A small
value, high quality capacitor is
used to bypass the RF/LO frequencies and a large value capacitor
for the IF. When biased in the high
linearity mode, a resistor is added
from the Source Bypass pin to
ground.
High Linearity Mode
The IAM-91563 has a feature that
allows the user to place an
external resistor from the Source
Bypass pin to ground and increase
the device current from a nominal
7-143
P1 dB and INPUT IP3 (dBm)
connected directly to a preceding
stage that has a voltage present, a
DC blocking capacitor should be
used.
-2
IP3
-4
P1 dB
-6
-8
-10
7
9
11
13
15
17
19
DEVICE CURRENT (mA)
1000 56
21
9
5
3
Approximate Resistor Value (Ω)
Figure 27. One dB Compression and
Input Third Order Intercept Point vs.
Device Current (Resistor).
As an example of improved
linearity, the use of a 15 Ω resistor
at the Source Bypass pin increases
the device current to 14 mA. At
1.9␣ GHz, the input IP 3 is increased
from -6.5 dBm to -3 dBm. Increasing the LO drive level from -5 dBm
to -1 dBm further increases the
input IP3 to 0 dBm.
LO
H
RF
IF
+V
IAM-91
Figure 28. PCB Layout.
1.9 GHz Design Example
To illustrate a design approach for
using the IAM-91563, a PCS band
downconverter with an RF of
1.9␣ GHz and IF of 110 MHz is
presented. The PCB layout above
was used to assemble the mixer
and verify performance.
LO
Input
RF
Input
C7
C1
C5
Vd
C6
L3
L1 = 0
RFC
91
Application Example
The printed circuit layout in
Figure 28 is a general purpose
layout that will accommodate
components for using the
IAM-91563 for RF inputs from
800␣ MHz to 6 GHz. This layout is a
microstripline design (solid
groundplane on the backside of
the circuit board) with 50 Ω
interfaces for the RF input, IF
output, and LO input. The circuit
is fabricated on 0.031-inch thick
FR-4 dielectric material. Plated
through holes (vias) are used to
bring the ground to the top side of
the circuit where needed. Multiple
vias are used to reduce the
inductance of the paths to ground.
MLIN
IF
Output
L2
C3
C4
C2
Figure 29. Schematic of Example
Application Circuit.
At the RF input port, series
capacitor C1 and transmission line
MLIN form the input matching
network and high pass filter.
(Note: The PCB layout above has
provision for an inductor, L1, in
series with MLIN. Inductor L1 is
not used in this design.)
Referring to the table of Reflection Coefficients, the RF input
port ΓRF = 0.82 ∠−37° at 1.9 GHz.
This point is plotted as Point A on
the Smith chart in Figure 30. For
reasons previously discussed in
the “RF Port” section above, a
series C - shunt L network (from
the 50 Ω source to ΓRF) will be
used to match ΓRF to 50 Ω.
Addition of a 6.5 nH shunt inductance moves the impedance
trajectory from Point A to Point B.
The match to 50 Ω is completed
with a 0.6 pF series capacitance,
C1, that moves the match to
Point␣ C, the center of the Smith
chart.
1
0.5
2
B
0.2
A schematic diagram of the
1.9␣ GHz circuit is shown in
Figure␣ 29.
0.2
C
-0.2
1
C
0.5
B
RF C1
Input
2
For this example, the shunt
inductor was realized with the
transmission line, MLIN in Figure␣ 29 ( Z O = 90 Ω, length =
0.35␣ in.). A high quality capacitor
should be selected for C1 to
minimize the effects of the
capacitor’s parasitic inductance
and resistance. Series capacitor
C1 also serves to block any DC
that may be present at the output
of the stage preceding the mixer.
At the IF output, the low pass
filter and impedance match is
formed by shunt capacitor C2 and
series inductor L2. Referring again
to the table of Reflection Coefficients, the IF output port ΓIF =
0.64 ∠ -8° at 100 MHz, which is the
frequency point closest to the
desired IF of 110 MHz. ΓIF is
plotted as Point A in Figure 31.
1
0.5
2
A
0.2
B
L2
C2
0.2
0.5
1
C
-0.2
C
IF
Output
2
A
B
-2
-0.5
-1
Figure 31. IF Input Impedance Match.
Adding a shunt capacitance (C2)
of 11.3 pF brings the impedance to
Point B. The match to Point C at
the center of the chart is completed with a series inductance
(L2) of 150 nH.
A
L
A
-2
-0.5
-1
Figure 30. RF Input Impedance
Match.
7-144
Although not necessary for many
applications, the match at the LO
port can be improved by the
addition of series inductor L3 with
a value of approximately 8 nH.
Design information (ΓLO) for
matching the LO port is obtained
from the table of Reflection
Coefficients. Capacitor C7 is a DC
block for the LO port.
DC bias is applied to the
IAM-91563 through the RFC at the
IF Output pin. The power supply
is bypassed to ground with
capacitor C5 to keep RF, IF, and
LO signals off of the DC bias lines
and to prevent gain dips or peaks
in the response of the mixer. C4 is
a DC blocking capacitor for the
output.
The values of the RF bypass
capacitors and DC blocking
capacitors that are not part of a
impedance matching structure
(i.e., C3 - C7) should be chosen to
provide a small reactance (typically < 5 ohms) at the lowest
frequency at the port for which
they are used. The reactance of
the RF choke (RFC) should be
high (e.g., several hundred ohms)
at the lowest IF.
The completed 1.9 GHz mixer
from the design example above
with all components and SMA
connectors in place is shown in
Figure 32. Again, L1 is not used
and is replaced by a metal tab.
The length of the shunt transmission line, MLIN, is adjustable by
moving the position of the shorting tab between the line and the
ground pad. Provision is made for
an additional bypass capacitor,
C6, to be added to the bias line
near the Vd connection to eliminate unwanted RF feedback
through bias lines.
When multiple bypass capacitors
are used, consideration should be
given to potential resonances. It is
important to ensure that the
capacitors, when combined with
additional parasitic L’s and C’s on
the circuit board, do not form
resonant circuits. The addition of
a small value resistor in the bias
supply line between bypass
capacitors will often “de-Q” the
bias circuit and eliminate resonance effects.
The values shown in Table 1 may
vary from those used above to
describe the basic impedance
matching approach. The final
component values take into
consideration additional effects
such as, the various line lengths
between components, parasitics
in components (e.g., the series
inductance in C1), as well as
other circuit parasitics. A CAD
program such as HP Touchstone®
may be used to fully analyze and
account for these circuit
variables.
Table 1 below summarizes the
component values for the 1.9 GHz
design.
Component
C1
C2
C3, C5, C7
C4
L1
L2
L3
MLIN
Value
0.5 pF
9 pF
100 pF
500 pF
(not used)
100 nH
8.2 nH
Zo=90 Ω
l = 0.41 in.
320 nH
RFC
Table 1. Component Values for
1.9␣ GHz Downconverter.
H
LO
C2
C7
RF
L2
L3
C4
RFC
C5
C1
C3
IF
L1
MUN 1
IAM-91
+V
C6
Figure 32. Complete 1.9 GHz Mixer.
The following performance was measured for a 1.9 GHz circuit:
Measured results:
Conversion Gain = 9.0 dB
SSB Noise Figure = 8.5 dB
P1dB (output) = -8.1 dB
IP3 (Input) = -7 dBm
Operating conditions:
RF Frequency = 1.89 GHz
LO Frequency = 1.78 GHz
IF Frequency = 110 MHz
7-145
LO-RF Isolation = 17 dB
LO-IF Isolation = 34 dB
RF-IF Isolation = 23 dB
LO Drive Level = -5 dBm
DC Power = 3.0V @ 9 mA
Designs for Other Frequencies
The same design methodology described above can be applied to other wireless frequency bands. Design
examples and measurement results for the 900 MHz and 2.4 GHz bands are shown in Figures 33 and 34.
100 pF
0.9 pF
Vd
50 Ω
RF
2450
MHz
220 pF
220 nH
GC
IF
250
MHz
GND
IF
180 nH
50 Ω
1000 pF
10 nH
RF
91
GN
LO
50 Ω
15 pF
LO
2200
MHz
Measured results:
Conversion Gain = 10.6 dB
SSB Noise Figure = 7.1 dB
1 dB Compression = -7.0 dB
P3 (Input) = -7 dBm
LO-RF Isolation = 21 dB
LO-IF Isolation = 33 dB
RF-IF Isolation = 17 dB
Operating conditions:
RF Frequency = 900 MHz
IF Frequency = 80 MHz
LO Frequency = 980 MHz
LO Drive Level = -5 dBm
DC Power = 3.0V @ 9 mA
Figure 33. 800-900 MHz Cellular and ISM Band Mixer.
100 pF
0.5 pF
Vd
100 pF
220 nH
68 nH
50 Ω
500 pF
RF
2450
MHz
110 Ω, 3 mm
GC
RF
91
GN
IF
250
MHz
50 Ω
IF
4.7 pF
GND
LO
3.3 nH
50 Ω
LO
2200
MHz
Measured results:
Conversion Gain = 7.7 dB
SSB Noise Figure = 11 dB
1 dB Compression = -8.7 dB
IP3 (Input) = -7 dBm
LO-RF Isolation = 16 dB
LO-IF Isolation = 35 dB
RF-IF Isolation = 27 dB
Operating conditions:
RF Frequency = 2.45 GHz
IF Frequency = 250 MHz
LO Frequency = 2.2 GHz
LO Drive Level = -5 dBm
DC Power = 3.0V @ 9 mA
Figure 34. 2.4 GHz ISM Band Mixer.
7-146
SOT-363 PCB Footprint
SMT Assembly
A recommended PCB pad layout
for the miniature SOT-363 (SC-70)
package used by the IAM-91563 is
shown in Figure 35 (dimensions
are in inches). This layout provides ample allowance for package placement by automated
assembly equipment without
adding parasitics that could
impair the high frequency RF
performance of the IAM-91563.
The layout is shown with a
nominal SOT-363 package footprint superimposed on the PCB
pads.
Reliable assembly of surface
mount components is a complex
process that involves many
material, process, and equipment
factors, including: method of
heating (e.g., IR or vapor phase
reflow, wave soldering, etc.)
circuit board material, conductor
thickness and pattern, type of
solder alloy, and the thermal
conductivity and thermal mass of
components. Components with a
low mass, such as the SOT-363
package, will reach solder reflow
temperatures faster than those
with a greater mass.
0.075
0.035
0.016
Figure 35. PCB Pad Layout
(dimensions in inches).
The IAM-91563 is has been
qualified to the time-temperature
profile shown in Figure 36. This
profile is representative of an IR
reflow type of surface mount
assembly process.
The rates of change of temperature for the ramp-up and cooldown zones are chosen to be low
enough to not cause deformation
of the board or damage to components due to thermal shock. The
maximum temperature in the
reflow zone (TMAX) should not
exceed 235 °C.
These parameters are typical for a
surface mount assembly process
for the IAM-91563. As a general
guideline, the circuit board and
components should be exposed
only to the minimum temperatures and times necessary to
achieve a uniform reflow of
solder.
After ramping up from room
temperature, the circuit board
with components attached to it
(held in place with solder paste)
250
TMAX
200
TEMPERATURE (°C)
0.026
passes through one or more
preheat zones. The preheat zones
increase the temperature of the
board and components to prevent
thermal shock and begin evaporating solvents from the solder paste.
The reflow zone briefly elevates
the temperature sufficiently to
produce a reflow of the solder.
150
Reflow
Zone
100
Preheat
Zone
Cool Down
Zone
50
0
0
60
120
180
TIME (seconds)
Figure 36. Surface Mount Assembly Profile.
7-147
240
300
Electrostatic Sensitivity
GaAs MMICs are
electrostatic discharge
(ESD) sensitive
devices. Although the
IAM-91563 is robust in design,
permanent damage may occur to
these devices if they are subjected
to high energy electrostatic
discharges. Electrostatic charges
as high as several thousand volts
(which readily accumulate on the
human body and on test equipment) can discharge without
detection and may result in
degradation in performance or
failure. The IAM-91563 is a ESD
Class 1 device. Therefore, proper
ESD precautions are recommended when handling, inspecting, and assembling these devices
to avoid damage.
7-148
Package Dimensions
Outline 63 (SOT-363/SC-70)
1.30 (0.051)
REF.
2.20 (0.087)
2.00 (0.079)
1.35 (0.053)
1.15 (0.045)
0.650 BSC (0.025)
0.425 (0.017)
TYP.
2.20 (0.087)
1.80 (0.071)
0.10 (0.004)
0.00 (0.00)
0.30 REF.
1.00 (0.039)
0.80 (0.031)
0.25 (0.010)
0.15 (0.006)
10°
0.30 (0.012)
0.10 (0.004)
0.20 (0.008)
0.10 (0.004)
DIMENSIONS ARE IN MILLIMETERS (INCHES)
Part Number Ordering Information
Part Number
IAM-91563-TR1
IAM-91563-BLK
No. of Devices
3000
100
Container
7" Reel
antistatic bag
7-149
Device Orientation
REEL
TOP VIEW
END VIEW
4 mm
8 mm
CARRIER
TAPE
91
91
91
91
USER
FEED
DIRECTION
COVER TAPE
Tape Dimensions and Product Orientation
For Outline 63
P
P2
D
P0
E
F
W
C
D1
t1 (CARRIER TAPE THICKNESS)
Tt (COVER TAPE THICKNESS)
K0
8° MAX.
A0
DESCRIPTION
5° MAX.
B0
SYMBOL
SIZE (mm)
SIZE (INCHES)
CAVITY
LENGTH
WIDTH
DEPTH
PITCH
BOTTOM HOLE DIAMETER
A0
B0
K0
P
D1
2.24 ± 0.10
2.34 ± 0.10
1.22 ± 0.10
4.00 ± 0.10
1.00 + 0.25
0.088 ± 0.004
0.092 ± 0.004
0.048 ± 0.004
0.157 ± 0.004
0.039 + 0.010
PERFORATION
DIAMETER
PITCH
POSITION
D
P0
E
1.55 ± 0.05
4.00 ± 0.10
1.75 ± 0.10
0.061 ± 0.002
0.157 ± 0.004
0.069 ± 0.004
CARRIER TAPE
WIDTH
THICKNESS
W
t1
8.00 ± 0.30
0.255 ± 0.013
0.315 ± 0.012
0.010 ± 0.0005
COVER TAPE
WIDTH
TAPE THICKNESS
C
Tt
5.4 ± 0.10
0.062 ± 0.001
0.205 ± 0.004
0.0025 ± 0.00004
DISTANCE
CAVITY TO PERFORATION
(WIDTH DIRECTION)
F
3.50 ± 0.05
0.138 ± 0.002
CAVITY TO PERFORATION
(LENGTH DIRECTION)
P2
2.00 ± 0.05
0.079 ± 0.002
7-150
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