PRELIMINARY DATA SHEET • SKY73134 FREQUENCY SYNTHESIZER

Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

6

December 15, 2009 • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • 201199A

PLL Control Registers (R-Divider and N-Divider)

There are three digital PLL control registers that are used to store

the R-divider and N-divider values: R_DIV, N_DIV1, and N_DIV2.

By default, all registers are 25 bits wide. Bit[21] is the read/write

bit, cleared when writing to the device. Bits[20:16] are the

address bits of the registers. The 16 least significant bits (LSBs)

represent the data bits.

Three values are needed to calculate the three PLL dividers,

VCO divider, D:

D

F

F

RF

VCO

(1)

The VCO divider (equal to 1, 2, 3, 4, or 8) is chosen so that the

D

F

F

STEP

COMP

(2)

The R_DIV register stores the value of the 16-bit R-divider that

according to the following equation:

COMP

REF

F

F

R

(3)

The N_DIV1 and N_DIV2 registers store the value of the N-divider

according to the following equation:

R

F

F

N

REF

VCO

(4)

Bits[1:0] of the N_DIV2 register are the most significant bits

(MSBs) of the 18-bit representation of the N number.

Bits[15:0] of the N_DIV1 register are the LSBs of the 18-bit binary

representation of the N number.

The calculated R-divider and N-divider values are programmed

into the SKY73134 using the SPI interface.

Additional programming information is provided in the Skyworks

document, SKY73134 Frequency Synthesizer Programming Guide,

document number *** TBD ***.

Example:

A desired RF output frequency of 2000 MHz is required using a

reference frequency of 38.4 MHz and a desired frequency step

size of 100 kHz. If the VCO divider is equal to 2, the VCO

frequency is 4000 MHz from Equation 1 and the comparison

frequency is equal to 200 kHz from Equation 2.

From Equations 3 and 4, the R and N values become:

R = 192 = 11000000b

N = 20000 = 100111000100000b

These values would be programmed through the SPI interface.

Figure 5 represents the bits of the R_DIV register with the value of

R = 192. Figures 6 and 7 represent the bits of the N_DIV1 and

N_DIV2 registers, respectively, with the value of N = 20000.

Electrical and Mechanical Specifications

The absolute maximum ratings of the SKY73134 are provided in

Table 3. The recommended operating conditions are specified in

Table 4 and electrical specifications are provided in Tables 5

through 7.

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

0

00

0

00

00

01

0

10

0

00

0

0

1

00

0

0

1

16-Bit R-Divider Value

3-Bit Device

Address

5-Bit Register

Address

1-Bit Read/Write Flag

S1847

Figure 5. R_DIV Register Showing an R-Divider Value of 192