SKY72302-21 Skyworks Solutions Inc, SKY72302-21 Datasheet - Page 5

• Manufacturer Part Number: SKY72302-21
• Description: IC SYNTHESIZER 6.1GHZ 28-EPTSSOP
• Manufacturer: Skyworks Solutions Inc
• Type: Fractional N Synthesizerr

Specifications of SKY72302-21

• Pll: Yes
• Input: Clock, Crystal
• Output: Clock, Crystal
• Number Of Circuits: 1
• Ratio - Input:output: 2:2
• Differential - Input:output: Yes/Yes
• Frequency - Max: 6.1GHz
• Divider/multiplier: Yes/No
• Voltage - Supply: 2.7 V ~ 3.3 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 28-TSSOP Exposed Pad, 28-eTSSOP, 28-HTSSOP
• Frequency-max: 6.1GHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 863-1079-2

Fractional-N Applications. The desired division ratio for the
main synthesizer is given by:
The desired division ratio for the auxiliary synthesizer is given by:
where N
synthesizer or between 37.5 and 537.5 for the auxiliary
synthesizer.
The value to be programmed by the Main or Auxiliary Divider
Register is given by:
NOTE: The Round function rounds the number to the nearest
When in fractional mode, allowed values for N
inclusive.
The value to be programmed by either of the MSB/LSB Dividend
Registers or the Auxiliary Dividend Register is given by:
where the divider is either 1024 in 10-bit mode or 262144 in
18-bit mode. Therefore, the dividend is a signed binary value
either 10 or 18 bits long.
NOTE: Because of the high fractionality of the SKY72302-21,
Sample calculations for two fractional-N applications are provided
in Figure 4.
Integer-N Applications. The desired division ratio for the main or
auxiliary synthesizer is given by:
where N
The value to be programmed by the Main or Auxiliary Divider
Register is given by:
When in integer mode, allowed values for N
for both the main and auxiliary synthesizers.
dividend
integer.
there is no practical need for any integer relationship
between the reference frequency and the channel spacing
or desired VCO frequencies.
fractional
integer
is an integer number from 32 to 543.
must be between 150 and 2150 for the main
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [e-mail] • www.skyworksinc.com
N
Round
101216L • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • September 9, 2009
N
N
reg
frac tion al
frac tion al
N
N
Round
[
reg
int
divider
eger
=
N
=
(
int
---------------------------------
F
N
4 F
F
F
eger
F
------------------------ -
vco
div
VCO_main
F
fractional
(
VCO_aux
_
_
div_r ef
N
main
ref
div_r ef
32
fractional
)
reg
32
reg
are from 0 to 511
are from 6 to 505
N
reg
32
)]
NOTE: As with all integer-N synthesizers, the minimum step size
A sample calculation for an integer-N application is provided in
Figure 5.
Register Loading Order. In applications where the main
synthesizer is in 18-bit mode, the Main Dividend MSB Register
holds the 10 MSBs of the dividend and the Main Dividend LSB
Register holds the 8 LSBs of the dividend. The registers that
control the main synthesizer’s divide ratio are to be loaded in the
following order:
In applications where the main synthesizer is in 10-bit mode, the
Main Dividend MSB Register holds the 10 bits of the dividend. The
registers that control the main synthesizer’s divide ratio are to be
loaded in the following order:
For the auxiliary synthesizer, the Auxiliary Dividend Register holds
the 10 bits of the dividend. The registers that control the auxiliary
synthesizer’s divide ratio are to be loaded in the following order:
NOTE: When in integer mode, the new divide ratios take effect as
Direct Digital Modulation
The high fractionality and small step size of the SKY72302-21
allow the user to tune to practically any frequency in the VCO’s
operating range. This allows direct digital modulation by
programming the different desired frequencies at precise
instants. Typically, the channel frequency is programmed by the
Main Divider and MSB/LSB Dividend Registers, and the
instantaneous frequency offset from the carrier is programmed by
the Modulation Data Register.
The Modulation Data Register can be accessed in three ways as
defined in the following subsections.
Main Divider Register
Main Dividend LSB Register
Main Dividend MSB Register (at which point the new divide ratio
takes effect)
Main Divider Register
Main Dividend MSB Register (at which point the new divide ratio
takes effect)
Auxiliary Divider Register
Auxiliary Dividend Register (at which point the new divide ratio
takes effect)
is related to the crystal frequency and reference frequency
division ratio.
soon as the Main or Auxiliary Divider Register is loaded.
DATA SHEET • SKY72302-21 FREQUENCY SYNTHESIZER
5