SKY72301-22 Datasheet, PDF (13/21 Pages) Skyworks Solutions Inc. – Spur-Free, 1.0 GHz Dual Fractional-N Frequency Synthesizer

DATA SHEET • SKY72301-22 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/Multiplexer Output Select Control 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
• Main Synthesizer ∆Σ Fractionality = One-bit flag to configure
the size of the main ∆Σ 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 ∆Σ modulator is 18-bit
with a fractionality of 218 and a step size of Fref_main/262144.
When this bit is set, the main ∆Σ modulator is 10-bit with a
fractionality of 210 and a step size of Fref_main/1024.
• Auxiliary Synthesizer Power Down = One-bit value 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.
• Auxiliary Synthesizer mode = One-bit value to power down the
auxiliary synthesizer’s ∆Σ 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
SKY72301-22.
• Multiplexer Output Selection = Three-bit value that selects
which internal signal is output to the Mux_out pin. Internal
signals available on this pin are the following:
− 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 and
auxiliary frequency dividers), F_{pd_main} or F_{pd_aux}
− Serial data out, for loop-back and test purposes
See Table 4 for more information.
• 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
200706B • Skyworks Proprietary and Confidential information • Products and Product Information are Subject to Change Without Notice • May 21, 2007
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