Si1000/1/2/3/4/5
fcarrier 10MHz(hbsel 1)(N F)
fc[15:0]
fTX 10MHz*(hbsel 1)*( fb[4:0] 24
)
64000
D7
D6
D5
D4
D3
D2
D1
D0 POR Def.
Add R/W
Function/
Description
73 R/W
74 R/W
Frequency
Offset 1
fo[7]
fo[6]
fo[5]
fo[4]
fo[3]
fo[2]
fo[1] fo[0]
fo[9] fo[8]
fb[1] fb[0]
fc[9] fc[8]
fc[1] fc[0]
00h
00h
35h
BBh
80h
Frequency
Offset 2
75 R/W Frequency Band
Select
sbsel
fc[14]
fc[6]
hbsel
fc[13]
fc[5]
fb[4]
fc[12]
fc[4]
fb[3]
fc[11]
fc[3]
fb[2]
fc[10]
fc[2]
76 R/W Nominal Carrier
Frequency 1
fc[15]
fc[7]
77 R/W Nominal Carrier
Frequency 0
The integer part (N) is determined by fb[4:0]. Additionally, the output frequency can be halved by connect-
ing a ÷2 divider to the output. This divider is not inside the loop and is controlled by the hbsel bit in "Regis-
ter 75h. Frequency Band Select". This effectively partitions the entire 240–960 MHz frequency range into
two separate bands: High Band (HB) for hbsel = 1, and Low Band (LB) for hbsel = 0. The valid range of
fb[4:0] is from 0 to 23. If a higher value is written into the register, it will default to a value of 23. The integer
part has a fixed offset of 24 added to it as shown in the formula above. Table 23.3 demonstrates the selec-
tion of fb[4:0] for the corresponding frequency band.
After selection of the fb (N) the fractional component may be solved with the following equation:
fTX
fc[15:0]
fb[4:0] 24 *64000
10MHz*(hbsel 1)
fb and fc are the actual numbers stored in the corresponding registers.
Table 23.3. Frequency Band Selection
fb[4:0] Value
N
Frequency Band
hbsel=0
hbsel=1
0
1
2
3
4
5
6
7
8
24
25
26
27
28
29
30
31
32
240–249.9 MHz
250–259.9 MHz
260–269.9 MHz
270–279.9 MHz
280–289.9 MHz
290–299.9 MHz
300–309.9 MHz
310–319.9 MHz
320–329.9 MHz
480–499.9 MHz
500–519.9 MHz
520–539.9 MHz
540–559.9 MHz
560–579.9 MHz
580–599.9 MHz
600–619.9 MHz
620–639.9 MHz
640–659.9 MHz
246
Rev. 1.0
SILICON [ SILICON ]
