SKY73103-11 Skyworks Solutions, Inc., SKY73103-11 Datasheet - Page 11

• Manufacturer Part Number: SKY73103-11
• Description: Sky73103-11 1460-1665 Mhz High Performance Vco/synthesizer With Integrated Switch
• Manufacturer: Skyworks Solutions, Inc.

Here, N is not equal to N
three LSBs (the 4
The fractional divisor code (FN) sets the fractional-N modulo up to
256 modulo according to the following equation:
The value of FN is equal to the binary representation of 256 (or 2
The fractional modulo can be extended up to 2
extender (ME) if required:
The value of ME is equal to the binary representation of the
integer part of 2
Example:
A desired synthesizer frequency of 1537.25 MHz is required using
a crystal frequency of 16 MHz and a 16/17 prescaler. Since the
maximum internal reference frequency is 25 MHz, the crystal
frequency does not need to be divided. However, a reference
divider ratio of 2 is used for this example.
Restating Equation 2 as a function of D
Where: RF = 1537.26
Determine N
fractional portion:
Using Equation 3:
Where: M
M = M
A = A
N = M 2
Multiply the fractional portion that was removed in the previous
step by 256 and remove the fractional portion of the result to
determine FN:
FN
ME
actual
actual
actual
FN
actual
P = 16
A
, or:
actual
actual
actual
ME = D
R1 = 2
F
= 12 = 1100b (the four LSBs)
= D
4
REF
= 11 = 001011b (the six MSBs)
+ A = 0010111100b (this is the same as N
FN = D
actual
= 12
= 16
= 11
14
D
Total
(1/2
D
23
by subtracting 3.5 from D
N
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [e-mail] • www.skyworksinc.com
th
7
14
200649D • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • November 30, 2009
actual
bit of the A-counter is a “don’t care” bit).
7
9
1
2
= (1537.26 2)/16 = 192.1575
ME
) + D
2
D
= 188 = M
2
14
Total
actual
actual
7
D
+ D
13
+ D
6
– 3.5 = 188.6575
(1/2
, or:
. The A-counter portion only uses the
2
13
1
6
2
10
) + D
2
2
actual
6
D
13
+ D
5
+ D
12
2
Total
1
(1/2
3
5
P + A
12
:
Total
2
11
5
) + . . . + D
2
+ . . . D
actual
and removing the
12
23
+ . . .D
using the modulo
D
0
0
actual
0
2
0
1
(1/2
8
)
23
)
(4)
8
)
0.6575 256 = 168.32
FN = 168 = 10101000b
Divide FN by 256 to determine the actual fractional part, FN
FN
Subtract this result from the fractional portion of (D
determine the actual fractional modulus extender, ME
ME
Multiply this result by 8388608 (the 23-bit
2
ME:
0.00125 8388608 = 10485.76
ME = 10485 = 010100011110101b
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 SKY73103-11 is rated to Moisture Sensitivity Level 3 (MSL3)
at 260 C. It can be used for lead or lead-free soldering. For
additional information, refer to Skyworks Application Note, PCB
Design and SMT Assembly/Rework Guidelines for MCM-L
Packages, document number 101752.
Care must be taken when attaching this product, whether it is
done manually or in a production solder reflow environment.
Production quantities of this product are shipped in a standard
tape and reel format. For packaging details, refer to the Skyworks
Application Note, Tape and Reel, document number 101568.
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 and as low
2. The ground pad of the SKY73103-11 provides critical
23
actual
) and remove the fractional portion to determine the value of
actual
impedance as possible.
electrical grounding requirements. Design the connection to
the ground pad to provide the best electrical connection to the
circuit board. Multiple vias to the grounding layer are
recommended to connect the top layer ground area to the
main ground layer.
= 168/256 = 0.65625
= (D
= 0.6575 – 0.65625
= 0.00125
Total
– 3.5 – N
DATA SHEET • SKY73103-11 VCO/SYNTHESIZER
actual
) – FN
actual
modulator value,
Total
actual
– 3.5) to
:
actual
:
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