SKY73012-11 Datasheet, PDF (16/25 Pages) Skyworks Solutions Inc. – SKY73012 400 – 3900 MHz Direct Quadrature Demodulator

DATA SHEET • SKY73012 DEMODULATOR
Evaluation Board Description
The SKY73012 Evaluation Board is used to test the performance
of the SKY73012 direct quadrature demodulator. There are three
Evaluation Boards for this device, each configured for a specific
frequency range. Each of these boards is described by the
following Figures and Tables:
• 800 to 1000 MHz: Figure 60 (schematic), Table 5 (component
values), and Figure 61 (assembly diagram)
• 1800 to 3900 MHz: Figure 62 (schematic), Table 6 (component
values), and Figure 63 (assembly diagram)
• Custom Frequency: Figure 64 (schematic), Table 7 (component
values), and Figure 65 (assembly diagram)
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 SKY73012 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
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 SKY73012 Evaluation
Board for testing. Refer to Figure 66 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 SKY73012 Evaluation Board can be
permanently damaged.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [e-mail] • www.skyworksinc.com
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January 12, 2007 • Skyworks Proprietary and Confidential information • Products and Product Information are Subject to Change Without Notice • 200473B