SKY73009 Datasheet, PDF (13/22 Pages) Skyworks Solutions Inc. – 400 -3000 MHz Direct Quadrature Demodulator

DATA SHEET • SKY73009 DEMODULATOR
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19
18
17
16
15
14
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12
2300
LO = -6 dBm
LO = 0 dBm
LO = +3 dBm
2350
2400
Frequency (MHz)
2450
2500
Figure 53. NF vs Frequency: 2300-2500 MHz
(Murata LDB15C500A2400 Balun on RF Port)
Evaluation Board Description
The SKY73009 Evaluation Board is used to test the performance
of the SKY73009 direct quadrature demodulator. There are three
Evaluation Boards for this device, each configured for a specific
frequency range. Schematic diagrams and Bills of Materials
(BOMs) for each board are presented in the following Figures and
Tables:
• Figure 55 and Table 5 (800-1000 MHz)
• Figure 56 and Table 6 (1500-2500 MHz)
• Figure 57 and Table 7 (custom frequency)
The Evaluation Board assembly diagram is shown in Figure 58
(800-1000 MHz), Figure 59 (1500-2500 MHz), and Figure 60
(custom frequency).
Circuit Design Considerations
The following design considerations are general in nature and
must be followed regardless of final use or configuration.
1. Paths to ground should be made as short as possible.
2. The ground pad of the SKY73009 direct quadrature
demodulator has special electrical and thermal grounding
requirements. This pad is the main thermal conduit for heat
dissipation. Since the circuit board acts as the heat sink, it
must shunt as much heat as possible from the device. As
such, design the connection to the ground pad to dissipate the
maximum wattage produced to the circuit board.
3. Two external output bypass capacitors are required on the
VCC pin. The values of these capacitors will change with
respect to the desired RF frequency. One capacitor should be
used for low frequency bypassing and the other capacitor for
high frequency bypassing. Special attention should be given
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19
18
17
16
15
14
13
12
11
10
2300
Vdd = 2.7V
Vdd = 3.0V
Vdd = 3.3V
2350
2400
Frequency (MHz)
2450
2500
Figure 54. NF vs Frequency: 2300-2500 MHz
(Murata LDB15C500A2400 Balun on RF Port)
so that the smaller value capacitor does not go into self-
resonance at the desired RF frequency.
4. The RF input must be driven differentially. A 1:1 impedance
ratio balun is recommended with a center tap on the
secondary side that is DC grounded.
Testing Procedure
Use the following procedure to set up the SKY73009 Evaluation
Board for testing. Refer to Figure 61 for guidance:
1. Connect a +3.0 VDC power supply using an insulated supply
cable. If available, enable the current limiting function of the
power supply to 100 mA.
2. Connect a signal generator to the RF signal input port. Set it to
the desired RF frequency at a power level of 0 dBm to the
Evaluation Board but do NOT enable the RF signal.
3. Connect a signal generator to the LO signal input port. Set to
the desired LO frequency at a power level of 0 dBm, but do
not enable.
4. Connect a spectrum analyzer to the IFI signal output port and
terminate the IFQ signal input port in 50 Ω.
5. Enable the power supply.
6. Enable the LO input signal.
7. Enable the RF signal.
8. Take measurements and repeat these steps for channel Q.
CAUTION: If any of the input signals exceed the rated maximum
values, the SKY73009 Evaluation Board can be
permanently damaged.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [e-mail] • www.skyworksinc.com
103034F • Skyworks Proprietary and Confidential information • Products and Product Information are Subject to Change Without Notice • February 13, 2006
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