S1T8825B

1.3GHZ DUAL PLL

12

CHANNEL 1, CHANNEL 2 PROGRAMMABLE N COUNTER

These programmable dividers are composed of a 5-bit swallow counter (5-bit programmable divider),

12-bit programmable main counter, and two-modulus prescalers providing 64 and 66 divisions.

Sending certain data to the swallow counter and the 12-bit programmable main counter allows the setting of any of

2048 to 262142 divisions (multiple of two).

The 12-bit programmable divider and swallow counter are set by each channel;

each channel is identified by a group code.

Figure 5.

5-BIT SWALLOW COUNTER DIVISION RATIO (A COUNTER)

12-BIT MAIN COUNTER DIVISION RATIO (B COUNTER)

B = N6

Division ratio: 3 to 4095

Data is shifted in LSB first

A = N1

Division ratio: 0 to 31, B

≥ A

Division Ratio

(A)

N5

N4

N3

N2

N1

0

00000

1

00001

•

•••••

31

11111

Division

Ratio (B)

N17

N16

N15

N14

N13

N12

N11

N10

N9

N8

N7

N6

3

000

000000011

4

000

000000000

•

•••

•••••••••

4095

111

111111111

N1

N2

N3

N4

N5

N6

N7

N8

N9

N10

N11

N12

N13

N14

N15

N16

N17

N18

N19

LSB

Swallow counter

Division Ratio of the N Counter, N

main counter

Group Code

CH1 = "10"

CH2 = "01"

MSB