SKY72302-21 Skyworks Solutions Inc, SKY72302-21 Datasheet - Page 6

• 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

DATA SHEET • SKY72302-21 FREQUENCY SYNTHESIZER
6
Case 1: To achieve a desired F
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [e-mail] • www.skyworksinc.com
September 9, 2009 • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • 101216L
of the synthesizer in 18-bit mode. Since the maximum internal reference frequency (F
frequency is divided by 2 to obtain a F
The value to be programmed in the Main Divider Register is:
With the modulator in 18-bit mode, the value to be programmed in the Main Dividend Registers is:
where 11 0000 0101 is loaded in the MSB of the Main Dividend Register and 1100 1100 is loaded in the LSB of the
Main Dividend Register.
Summary:
· · Main Divider Register = 0 0010 1010
· · Main Dividend Register, LSB = 1100 1100
· · Main Dividend Register, MSB = 11 0000 0101
· · The resulting main VCO frequency is 5900.4529 MHz
Note: The frequency step size for this case is 4 x 20 MHz divided by 2
N
N
dividend = Round[divider × (N
fractional
reg
= Round[N
= Round[73.755663] – 32
= 74 – 32
= 42 (decimal)
= 000101010 (binary)
= Round[262144 × (73.755663 – 42 – 32)]
= Round[262144 × (–0.2443375)]
= Round[–64051.6096]
= –64052 (decimal)
= 110000010111001100 (binary)
= F
= 5900.4530
= 73.755663
Figure 4. Fractional-N Applications: Sample Calculation (1 of 2)
4 x F
vco_main
vco_main
fractional
80
div_ref
frequency of 5900.4530 MHz using a crystal frequency of 40 MHz with operation
] – 32
fractional
div_ref
of 20 MHz. Therefore:
– N
reg
– 32)]
18
, giving 305.2 Hz.
div_ref
) is 25 MHz, the crystal
C1449