LMX2320TM National Semiconductor, LMX2320TM Datasheet - Page 11

• Manufacturer Part Number: LMX2320TM
• Description: IC FREQ SYNTH 2.0GHZ 20-TSSOP
• Manufacturer: National Semiconductor
• Series: PLLatinum™r
• Type: PLL Frequency Synthesizerr

Specifications of LMX2320TM

• Pll: Yes
• Input: CMOS, TTL
• Output: CMOS
• Number Of Circuits: 1
• Ratio - Input:output: 1:1
• Differential - Input:output: Yes/No
• Frequency - Max: 2GHz
• Divider/multiplier: Yes/No
• Voltage - Supply: 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 20-TSSOP
• Frequency-max: 2.5GHz
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: *LMX2320TM

Functional Description
PROGRAMMABLE DIVIDER (N COUNTER)
The N counter consists of the 7-bit swallow counter (A counter) and the 11-bit programmable counter (B counter). If the Control
Bit (last bit shifted into the Data Register) is LOW, data is transferred from the 19-bit shift register into a 7-bit latch (which sets
the 7-bit Swallow (A) Counter) and an 11-bit latch (which sets the 11-bit programmable (B) Counter). Serial data format is shown
below.
Note: S8 to S18: Programmable counter divide ratio control bits (3 to 2047)
7-BIT SWALLOW COUNTER DIVIDE RATIO
(A COUNTER)
Note: Divide ratio: 0 to 127
B
11-BIT PROGRAMMABLE COUNTER DIVIDE RATIO
(B COUNTER)
Note:
Divide ratio: 3 to 2047 (Divide ratios less than 3 are prohibited)
B
PULSE SWALLOW FUNCTION
f
f
B:
A:
f
R:
P:
VCO
VCO
OSC
Divide
Divide
Ratio
Ratio
2047
127
A
A
A
0
1
B
•
3
4
•
:
:
= [(P x B) + A] x f
Output frequency of external voltage controlled os-
cillator (VCO)
Preset divide ratio of binary 11-bit programmable
counter (3 to 2047)
Preset divide ratio of binary 7-bit swallow counter
(0
Output frequency of the external reference fre-
quency oscillator
Preset divide ratio of binary 14-bit programmable
reference counter (3 to 16383)
Preset modulus of dual moduIus prescaler (64 or
128 for 2315/20 or 32 or 64 for 2325)
S
7
0
0
1
18
•
S
0
0
1
•
A
S
6
0
0
1
•
17
S
0
0
1
•
127, A
S
5
0
0
1
•
16
S
0
0
1
•
S
1
4
0
0
•
OSC
15
S
0
0
1
•
B)
S
3
0
0
1
•
/R
14
S
0
0
1
•
S
2
0
0
1
•
13
S
S
1
0
1
1
0
0
1
•
•
12
S
0
0
1
•
(Continued)
11
S
0
0
1
•
10
S
0
1
1
•
S
9
1
0
1
•
S
8
1
0
1
•
11
DS012339-20
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