LMX2430 National Semiconductor Corporation, LMX2430 Datasheet - Page 43

• Manufacturer Part Number: LMX2430
• Description: Pllatinum Dual High Frequency Synthesizer For Rf Personal Communications
• Manufacturer: National Semiconductor Corporation

Reg
R3
2.0 Programming Description
2.7 R3 REGISTER
The R3 register contains the IF_R, IF_CPP, IF_CPG, IF_CPT, and IF_RST control words, in addition to two of the four bits that
compose the MUX control word. The detailed descriptions and programming information for each control word is discussed in the
following sections.
2.7.1 IF_R[14:0] - IF Synthesizer Programmable Reference Divider (R Counter) (R3[17:3])
The IF reference divider (IF_R) can be programmed to support divide ratios from 3 to 32767. Divide ratios less than 3 are
prohibited.
2.7.2 IF_CPP - IF Synthesizer Phase Detector Polarity (R3[18])
The IF_CPP bit is used to control the IF synthesizer’s phase/ frequency detector polarity based on the VCO tuning characteristics.
MUX[1:0]
23
Divide Ratio
32767
22
3
4
•
Control Bit
IF_CPP
RST
IF_
21
CPT
IF_
20
CPG
IF_
19
14
0
0
1
•
CPP
IF_
18
Register Location
13
0
0
1
•
17
R3[18]
12
0
0
1
•
16
11
15
0
0
1
•
DATA[20:0] FIELD
IF VCO Characteristics
14
(Continued)
IF Phase/ Frequency
Detector Polarity
10
0
0
1
•
13
Description
9
0
0
1
•
12
43
8
0
0
1
11
•
IF_R[14:0]
IF_R[14:0]
10
7
0
0
1
•
IF VCO Negative
Tuning
Characteristics
9
20053568
6
0
0
1
•
8
0
5
0
0
1
•
7
Function
6
4
0
0
1
•
IF VCO Positive
Tuning
Characteristics
5
3
0
0
1
•
4
1
2
0
1
1
•
3
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2
0
1
1
0
1
•
ADDRESS
FIELD
[2:0]
1
1
0
1
0
1
•
0
1