April 1, 2009 • Skyworks Proprietary and Confidential information • Products and Product Information are Subject to Change Without Notice • 200990B
DATA SHEET • SKY73085-11 DOWNCONVERSION MIXER
Functional Description
The SKY73085-11 is a high gain diversity mixer, optimized for
base station receiver applications. The device consists of two
diversity channels, each consisting of a low loss RF balun, high
linearity passive mixer, and a low noise IF amplifier.
LO amplifiers are also included that allow the SKY73085-11 to
connect directly to the output of a Voltage Controlled Oscillator
(VCO). This eliminates the extra gain stages needed by most
discrete passive mixers. A Single Pole, Double Throw (SPDT)
switch has been included to select between two different LO
inputs for frequency hopping applications (i.e., GSM).
RF Baluns and Passive Mixer
The RF baluns provide a single ended input, which can easily be
matched to 50
Ω
using a simple matching circuit. The RF
baluns offer very low loss and excellent amplitude and phase
balance.
The high linearity mixer is a passive, double balanced mixer that
provides a very low insertion loss, and excellent 3
rd
Order Input
Insertion Point (IIP3) and linearity performance.
Additionally, the balanced nature of the mixer provides for
excellent port-to-port isolation.
LO Buffers and SPDT LO Switch
The LO buffers allow the input power of the SKY73085-11 to be
programmed in the range of –6 to +6 dBm. The LO section has
been optimized for high-side LO injection. However, the LO can
be driven over a wide frequency range with only slight
degradation in performance.
A high isolation SPDT switch allows the SKY73085-11 to be
used for frequency hopping applications. This switch provides
greater than 60 dB of LO1 to LO2 isolation:
LO_SEL Logic:
High
Low (default)
LO Path Enabled:
Pin 19 (LO1)
Pin 27 (LO2)
For applications that do not require frequency hopping, LO_SEL
is fixed to one state and the appropriate LO input is used. An
internal pull-down resistor on pin 23 (LO_SEL) sets the default
LO path to LO2.
IF Amplifier
The SKY73085-11 includes high dynamic range IF amplifiers
that follow the passive mixers in the signal path. The outputs
require a supply voltage connection using inductive chokes.
These choke inductors should be high-Q and have the ability to
handle 200 mA or greater.
A simple matching network allows the output ports to be
matched to a balanced 200
Ω
impedance. The IF amplifiers are
optimized for IF frequencies between 40 and 250 MHz. The IF
amplifiers can be operated outside of this range, but with a
slight degradation in performance.
Electrical and Mechanical Specifications
The absolute maximum ratings of the SKY73085-11 are
provided in Table 2. The recommended operating conditions are
specified in Table 3 and electrical specifications are provided in
Table 4.
Typical performance characteristics of the SKY73085-11 are
illustrated in Figures 3 through 28.
Table 2. SKY73085-11 Absolute Maximum Ratings
Parameter
Supply voltage, +5 V (VCC1 – VCC7)
Supply current
RF input power
LO input power
Operating case temperature
Junction temperature
Storage case temperature
Note:
Symbol
VCC
I
CC
P
RF
P
LO
T
C
T
J
T
STG
Minimum
4.5
Typical
5.0
350
Maximum
5.5
420
20
Units
V
mA
dBm
dBm
°C
°C
°C
0
–40
20
+85
+150
–40
+125
Exposure to maximum rating conditions for extended periods may reduce device reliability. There is no damage to device with only one parameter set at the limit and all other
parameters set at or below their nominal value.
Nominal thermal resistance (junction to center ground pad) is 5.1
April 1, 2009 • Skyworks Proprietary and Confidential information • Products and Product Information are Subject to Change Without Notice • 200990B
DATA SHEET • SKY73085-11 DOWNCONVERSION MIXER
Table 4. SKY73085-11 Electrical Specifications (2 of 2)
(Voltage Supply = +5 V, T
C
= +25
°C,
LO = 0 dBm, RF Frequency = 450 MHz, IF Frequency = 90 MHz, LO Frequency = 540 MHz, Unless
Otherwise Noted)
Parameter
RF to IF isolation
LO leakage:
1xLO to RF port
2xLO to RF port
3xLO to RF port
4xLO to RF port
1xLO to IF port
Symbol
Test Condition
F
RF
= 450 MHz
F
LO
= 540 MHz
–30
–29
–44
–40
–40
–25
–25
–28
–28
–23
dBm
dBm
dBm
dBm
dBm
Min
30
Typical
63
Max
Units
dB
Note 1:
The SKY73085-11 has been optimized for high-side LO injection. However, the LO can be used outside of the specified frequency range with degraded performance.
12.0
11.5
11.0
10.5
4.75 V
5.00 V
5.25 V
12.0
11.5
11.0
10.5
–40
C
+25
o
C
+85
C
Gain
(dB)
Gain
(dB)
10.0
9.5
9.0
8.5
8.0
7.5
7.0
435
445
455
465
475
485
10.0
9.5
9.0
8.5
8.0
7.5
7.0
435
445
455
465
475
485
RF Frequency (MHz)
RF Frequency (MHz)
Figure 3. Mixer A Gain vs Frequency and Supply Voltage
Figure 4. Mixer A Gain vs Frequency and Temperature
12.0
11.5
11.0
10.5
–3 dBm
0 dBm
+3 dBm
12.0
11.5
11.0
10.5
4.75 V
5.00 V
5.25 V
Gain
(dB)
10.0
9.5
9.0
8.5
8.0
7.5
7.0
435
445
455
465
475
485
Gain
(dB)
10.0
9.5
9.0
8.5
8.0
7.5
7.0
435
445
455
465
475
485
RF Frequency (MHz)
RF Frequency (MHz)
Figure 5. Mixer A Gain vs Frequency and LO Power
Figure 6. Mixer B Gain vs Frequency and Supply Voltage
12.0
12.0
11.5
11.0
10.5
–40
C
+25
o
C
+85
C
11.5
11.0
10.5
10.0
9.5
9.0
8.5
8.0
7.5
435
445
455
465
475
485
–3 dBm
0 dBm
+3 dBm
Gain
(dB)
10.0
9.5
9.0
8.5
8.0
7.5
7.0
Gain
(dB)
7.0
435
445
455
465
475
485
RF Frequency (MHz)
RF Frequency (MHz)
Figure 7. Mixer B Gain vs Frequency and Temperature
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