LMX2330L National Semiconductor Corporation, LMX2330L Datasheet - Page 15

• Manufacturer Part Number: LMX2330L
• Description: Pllatinum? Low Power Dual Frequency Synthesizer For Rf Personal Communications
• Manufacturer: National Semiconductor Corporation

Functional Description
PROGRAMMABLE MODES
Several modes of operation can be programmed with bits R16–R20 including the phase detector polarity, charge pump
TRI-STATE and the output of the F
programmable modes are shown in Table 1 . Truth table for the programmable modes and F
Table 3 .
Note 9: Refer to POWERDOWN OPERATION in Functional Description.
Note 10: The I
Note 11: PHASE DETECTOR POLARITY
0
1
Depending upon VCO characteristics, R16 bit should be set accordingly: (see figure right)
When VCO characteristics are positive like (1), R16 should be set HIGH;
When VCO characteristics are negative like (2), R16 should be set LOW.
Phase Detector Polarity
CPo
(Note 11)
Negative
Positive
LOW current state = 1/4 x I
C1
0
0
C2
0
1
Detector Polarity
Detector Polarity
RF Phase
Normal Operation
IF Phase
D
o
LD pin. The prescaler and powerdown modes are selected with bits N19 and N20. The
CPo
R16
o
TRI-STATE
C1
(Note 9)
1
1
TRI-STATE
(Continued)
HIGH current.
TABLE 2. Mode Select Truth Table
C2
0
1
TABLE 1. Programmable Modes
VCO Characteristics
RF Prescaler
RF I
IF Prescaler
IF I
R17
(Note 10)
CPo
N19
HIGH
CPo
LOW
I
CPo
15
TRI-STATE
TRI-STATE
Prescaler
RF D
IF D
R18
16/17
8/9
IF
o
o
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01280609
N20
2330L RF
Prescaler
32/33
64/65
RF LD
IF LD
R19
o
LD output are shown in Table 2 and
2331L/32L RF
Prescaler
128/129
64/65
RF F
IF F
R20
o
o
Pwrd Up
Pwrd Dn
(Note 9)
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Pwdn