Functional Description

The simplified block diagram below shows the 22-bit data register, two 15-bit R Counters and two 18-bit N Counters (intermediate

latches are not shown). The data stream is clocked (on the rising edge of Clock) into the DATA register, MSB first. The data stored

in the shift register is loaded into one of the 4 appropriate latches on the rising edge of LE. The last two bits are the Control Bits.

The DATA is transferred into the counters as follows:

Control Bits

DATA Location

C1

C2

0

0

RF2 R Counter

0

1

RF1 R Counter

1

0

RF2 N Counter

1

1

RF1 N Counter

PROGRAMMABLE REFERENCE DIVIDERS (RF1 AND RF2 R COUNTERS)

If the Control Bits are 00 or 01 (00 for RF2 and 01 for RF1) data is transferred from the 22-bit shift register into a latch which sets

the 15-bit R Counter. Serial data format is shown below.

15-BIT PROGRAMMABLE REFERENCE DIVIDER RATIO (R COUNTER)

Divide

RRRRRRRRRRRRRRR

Ratio 15 14 13 12 11 10

987654321

3

000000000000011

4

000000000000100

•

•••••••••••••••

32767

111111111111111

Notes:

Divide ratios less than 3 are prohibited.

Divide ratio: 3 to 32767

R1 to R15: These bits select the divide ratio of the programmable reference divider.

Data is shifted in MSB first.

DS012807-5

DS012807-6

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