sky73112-11 Skyworks Solutions, Inc., sky73112-11 Datasheet - Page 11

• Manufacturer Part Number: sky73112-11
• Description: Sky73112-11 750-850 Mhz High Performance Vco/synthesizer With Integrated Switch
• Manufacturer: Skyworks Solutions, Inc.

The value of ME is equal to the binary representation of the
integer part of 2
Example :
A desired synthesizer frequency of 850 MHz is required using a
crystal frequency of 52 MHz and an 8/9 prescaler. Since the
maximum internal reference frequency is 25 MHz, the crystal
frequency needs to be divided; a reference divider ratio of 8 is
used for this example.
Restating Equation (2) as a function of D
Where: RF = 850
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:
0.2692307692308 256 = 68.9230769230848
FN = 68 = 01000100b (the value programmed)
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
actual
actual
actual
actual
= 68/256 = 0.265625
= (D
P = 8
A
actual
actual
ME = D
R1 = 8
F
= 0.2692307692308 – 0.265625
= 0.0036057692308
= 7 = 0111b (the four LSBs)
4
D
REF
= 15 = 001111b (the six MSBs)
Total
+ A = 0011110111b (the value programmed)
Total
actual
= 7
= 52
= 15
– 3.5 – N
D
23
= (850 8)/52 = 130.7692307692308
by subtracting 3.5 from D
N
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [e-mail] • www.skyworksinc.com
Total
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200736B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • November 30, 2009
actual
ME
– 3.5 = 127.2692307692308
2
= 127 = M
14
actual
actual
+ D
, or:
) – FN
13
2
actual
actual
13
+ D
Total
P + A
12
Total
:
2
actual
and removing the
12
+ . . .D
Total
actual
– 3.5 to
0
:
actual
:
Multiply this result by 8388608 (the 23-bit
2
ME:
0.0036057692308 8388608 = 30247.3846156427264
ME = 30247 = 111011000100111b (the value programmed).
Refer to Tables 6 and 7 for the location of the resulting bits in the
ME parameter.
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 SKY73112-11 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 SKY73112-11 provides critical
3. Skyworks recommends including external bypass capacitors
4. A 50
23
) and remove the fractional portion to determine the value of
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.
on the VDD voltage input (pin 37) of the device. These
capacitors should be placed as close as possible to the VDD
input pin.
line.
impedance trace is needed for the RF_OUT (pin 10)
DATA SHEET • SKY73112-11 VCO/SYNTHESIZER
modulator value,
11