LMX2301 National Semiconductor Corporation, LMX2301 Datasheet - Page 7

• Manufacturer Part Number: LMX2301
• Description: Pllatinumtm 160 Mhz Frequency Synthesizer For Rf Personal Communications
• Manufacturer: National Semiconductor Corporation

Functional Description
PROGRAMMABLE DIVIDER (N COUNTER)
The N counter consists of the 11-bit programmable counter If the Control Bit (last bit shifted into the Data Register) is LOW
data is transferred from the 19-bit shift register into an 11-bit latch which sets the 11-bit programmable Counter Serial data
format is shown below
Note R8 to R18 Programmable counter divide ratio control bits (3 to 2047)
7 LSB BITS OF N REGISTER
Note X
11-BIT PROGRAMMABLE COUNTER DIVIDE RATIO
Note Divide ratio 3 to 2047 (Divide ratios less than 3 are prohibited)
Divide
Divide
Ratio
Ratio
2047
N
3
4
X
#
e
Don’t care state
18
N
X
N
7
0
0
1
#
N
6
X
17
N
0
0
1
#
N
5
X
16
N
0
0
1
#
N
4
X
15
N
0
0
1
#
N
X
3
14
N
0
0
1
#
N
X
2
13
N
0
0
1
#
N
X
1
12
(Continued)
N
0
0
1
#
11
N
0
0
1
#
10
N
0
1
1
#
N
9
1
0
1
#
N
8
1
0
1
#
7
EQUATION FOR OUTPUT FREQUENCY
DETERMINATION
f
f
N
f
R
VCO
VCO
OSC
e
Output frequency of external voltage controlled oscil-
lator (VCO)
Preset divide ratio of binary 11-bit programmable
counter (3 to 2047)
Output frequency of the external reference frequency
oscillator
Preset divide ratio of binary 14-bit programmable ref-
erence counter (3 to 16383)
N
c
f
OSC
R
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