SKY72300-21 Datasheet, PDF (14/23 Pages) Skyworks Solutions Inc. – SKY72300-21: Spur-Free, 2.1 GHz Dual Fractional-N Frequency Synthesizer

DATA SHEET • SKY72300-21 FREQUENCY SYNTHESIZER
A3 A2 A1 A0 11 10 9 8 7 6 5 4 3 2 1 0
1000X X
0 000
Reserved Bits
Modulation Data Magnitude Offset
Modulation Data Input Select
Modulation Address Disable
C1425
Figure 14. Modulation Control Register (Write Only)
A3 A2 A1 A0 11 10 9 8 7 6 5 4 3 2 1 0
1 0 0 1 MSB
LSB
Figure 15. Modulation Data Register (Write Only)
Modulation Data Bits
C1426
The Modulation Control Register is used to configure the
modulation unit of the main synthesizer. The modulation unit adds
or subtracts a frequency offset to the selected center frequency at
which the main synthesizer operates. The size of the modulation
data sample, controlled by the duration of the CS signal, can be
from 2 to 12 bits wide to provide from 4 to 4096 selectable
frequency offset steps.
The modulation data magnitude offset selects the magnitude
multiplier for the modulation data and can be from 0 to 8. As
shown in Figure 14, the values to be loaded are:
x Modulation Data Magnitude Offset = Four-bit value that
indicates the magnitude multiplier (m) for the modulation data
samples. Valid values range from 0 to 13, effectively providing a
2m multiplication of the modulation data sample.
x Modulation Data Input Select = One-bit flag to indicate the pin
on which modulation data samples are serially input when the
CS signal is between 2 and 12 bits long. When this bit is
cleared, modulation data samples are to be presented on the
Data pin. When this bit is set, modulation data samples are to
be presented on the Mod_in pin.
x Modulation Address Disable = One-bit flag to indicate the
presence of the address as modulation data samples are
presented on either the Mod_in or Data pins. When this bit is
cleared, the address is presented with the modulation data
samples (i.e., all transfers are 16 bits long). When this bit is set,
no address is presented with the modulation data samples (i.e.,
all transfers are 2 to 12 bits long).
The Modulation Data Register is used to load the modulation data
samples to the modulation unit. These values are transferred to
the modulation unit on the falling edge of F_{pd_main} where they are
passed to the main '6 modulator at the selected magnitude
offset on the next falling edge of F_{pd_main}. Modulation Data Register
values are 2's complement format. As shown in Figure 15, the
value to be loaded is:
x Modulation Data Bits = Modulation data samples that represent
the instantaneous frequency offset to the selected main
synthesizer frequency (selected channel) before being affected
by the modulation data magnitude offset.
Package and Handling Information
Since the device package is sensitive to moisture absorption, it is
baked and vacuum packed before shipping. Instructions on the
shipping container label regarding exposure to moisture after the
container seal is broken must be followed. Otherwise, problems
related to moisture absorption may occur when the part is
subjected to high temperature during solder assembly.
The SKY72300-21 is rated to Moisture Sensitivity Level 3 (MSL3)
at 260 qC. It can be used for lead or lead-free soldering.
Care must be taken when attaching this product, whether it is
done manually or in a production solder reflow environment.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [e-mail] • www.skyworksinc.com
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September 11, 2009 • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • 101217N