LMX2571_15 Datasheet, PDF (21/61 Pages) Texas Instruments – LMX2571 Low-Power, High-Performance PLLatinum™ RF Synthesizer with FSKModulation

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7.6.7 R40 Register (offset = 28h) [reset = 101Ch]
LMX2571
SNAS654 – MARCH 2015
Figure 26. R40 Register
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0
0
0
CP_IUP
CP_GAIN
0
1
1
1
0
0
R/W-0h
R/W-10h
R/W-0h
R/W-1Ch
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 7. R40 Register Field Descriptions
Bit
15-13
12-8
Field
CP_IUP
7-6 CP_GAIN
5-0
Type
R/W
R/W
Reset
0h
10h
R/W
0h
R/W
1Ch
Description
Program 0h to this field.
Set the base charge pump current for internal VCO in
synthesizer mode operation. The total base charge pump current
is equal to CP_IDN + CP_IUP. CP_IDN must be equal to
CP_IUP.
0 = Tri-state
1 = 156.25 µA
2 = 312.5 µA
3 = 468.75 µA
...
31 = 3593.75 µA
Set the multiplication factor to the base charge pump current for
internal VCO in synthesizer mode operation. For example, if the
gain here is 2x and if the total base charge pump current
(CP_IDN + CP_IUP) is 2.5 mA, then the final charge pump
current applied to the loop filter is 5 mA. The gain values are not
precise. They are provided as a quick way to boost the total
charge pump current for debug purposes or specific
applications.
0 = 1x
1 = 2x
2 = 1.5x
3 = 2.5x
Program 1Ch to this field.
7.6.8 R39 Register (offset = 27h) [reset = 11F0h]
Figure 27. R39 Register
15
14
13
12
11
10
9
8
7
6
5
0
0
0
1
0
0
0
1
1
1
1
R/W-11Fh
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
4
3
2
1
1 SDO_ 0
1
LD_SE
L
R/W-
0h
R/W-0h
0
LD_E
N
R/W-
0h
Bit
15-4
3
Field
SDO_LD_SEL
2-1
Table 8. R39 Register Field Descriptions
Type
R/W
R/W
Reset
11Fh
0h
R/W
0h
Description
Program 11Fh to this field.
Defines the MUXout pin function.
0 = Register readback serial data output
1 = Lock detect output
Program 1h to this field.
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