1.2 PROGRAMMABLE DIVIDER (N COUNTER)

The N counter consists of the 5-bit swallow counter (A counter) and the 13-bit programmable counter (B counter). If the Control

Bits are [C

a 13-bit latch (which sets the 13-bit programmable (B) Counter), and the GO bit (See Section 1.3.4 FastLock MODES section)

MSB first. For the LMX2306 the maximum N value is 65535 and the minimum N value is 56. For the LMX2316/26, the maximum

N value is 262143 and the minimum N value is 992. Serial data format is shown below.

10012706

Note: Data is shifted in MSB first.

1.2.1 5-bit Swallow Counter Divide Ratio (A Counter)

LMX2316/26

Divide

NNNN

N

Ratio

5432

1

0

0000

0

1

0000

1

•

••••

•

31

1111

1

Note: Divide ratio: 0 to 31

B

≥ A

LMX2306

Divide

NNNN

N

Ratio

5432

1

0X

X

0

0

0

Divide

NNNN

N

Ratio

5432

1

1X

X

0

0

1

•

••••

•

7X

X

1

1

1

Note: Divide ratio: 0 to 7

B

≥ A

X denotes a Don’t Care condition

1.2.2 13-Bit Programmable Counter Divide Ratio (B Counter)

Divide

NNNNNNNNN

N

N

N

N

Ratio

18

17

16

15

14

13

12

11

10

9

8

7

6

3

000000000

0

0

1

1

4

000000000

0

1

0

0

•

•••••••••

•

•

•

•

8191

111111111

1

1

1

1

Divide ratio: 3 to 8191 (Divide ratios less than 3 are prohibited)

B

≥A

1.2.3 Pulse Swallow Function

fvco = [(P x B) + A] x fosc/R

f

B:

Preset divide ratio of binary 13-bit programmable counter (3 to 8191)

A:

Preset divide ratio of binary 5-bit swallow counter (0

≤ A ≤ 31; A ≤ B for LMX2316/26)

or (0

≤ A ≤ 7, A ≤ B for LMX2306)

f

R:

Preset divide ratio of binary 14-bit programmable reference counter (3 to 16383)

P:

Preset modulus of dual modulus prescaler

for the LMX2306; P = 8

for the LMX2316/26; P = 32

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