SKY72300-21 Datasheet, PDF (13/23 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
0111X X
MSB
LSB
Full Power Down
Main Synthesizer Power Down
Main Synthesizer Mode
Main Synthesizer ΔΣ Fractionality
Auxiliary Synthesizer Power Down
Auxiliary Synthesizer Mode
Multiplexer Output Selection
Mux_out Pin Tri-State Enable
C1424
Figure 13. Power Down and Multiplexer Output Register (Write Only)
Table 4. Multiplexer Output
Multiplexer Output Select
(Bit 8)
0
0
0
0
1
1
1
1
Multiplexer Output Select
(Bit 7)
0
0
1
1
0
0
1
1
Multiplexer Output Select
(Bit 6)
0
1
0
1
0
1
0
1
Multiplexer Output
(Mux_out)
Reference Oscillator
Auxiliary Reference Frequency (Fref_aux)
Main Reference Frequency (Fref_main)
Auxiliary Phase Detector Frequency (Fpd_aux)
Main Phase Detector Frequency (Fpd_main)
Serial data out
Serial interface test output
Unused
x Main Synthesizer '6 Fractionality = One-bit flag to configure
the size of the main '6 modulator. This has a direct effect on
power consumption, and on the level of fractionality and step
size. When this bit is cleared, the main '6 modulator is 18-bit
with a fractionality of 218 and a step size of F_{ref_main}/262144.
When this bit is set, the main '6 modulator is 10-bit with a
fractionality of 210 and a step size of F_{ref_main}/1024.
x Auxiliary Synthesizer Power Down = One-bit flag to power down
the auxiliary synthesizer. When this bit is cleared, the auxiliary
synthesizer is powered up. When this bit is set, the auxiliary
synthesizer is in power-down mode.
x Auxiliary Synthesizer Mode = One-bit flag to power down the
auxiliary synthesizer’s '6 modulator and fractional unit to
operate as an integer-N synthesizer. When this bit is cleared,
the auxiliary synthesizer is in fractional-N mode. When this bit is
set, the auxiliary synthesizer is in integer-N mode.
NOTE: There are no special power-up sequences required for the
SKY72300-21.
x Multiplexer Output Selection = Three-bit value that selects
which internal signal is output to the Mux_out pin. The following
internal signals are available on this pin:
 Reference oscillator: F_ref
 Main or auxiliary divided reference (post-reference frequency
main or auxiliary dividers): F_{ref_main} or F_{ref_aux}
 Main or auxiliary phase detector frequency (post-main or
auxiliary frequency dividers): F_{pd_main} or F_{pd_aux}
 Serial data out for loop-back and test purposes
Refer to Table 4 for more information.
x Mux_out Pin Tri-State Enable = One-bit flag to tri-state the
Mux_out pin. When this bit is cleared, the Mux_out pin is
enabled. When this bit is set, the Mux_out pin is tri-stated.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [e-mail] • www.skyworksinc.com
101217N • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • September 11, 2009
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