ML145162 Просмотр технического описания (PDF) - LANSDALE Semiconductor Inc.

Номер в каталоге

Компоненты Описание

производитель

ML145162

60 MHz and 85 MHz Universal Programmable Dual PLL Frequency Synthesizers CMOS

LANSDALE Semiconductor Inc. 

ML145162

LANSDALE Semiconductor, Inc.

ADin

16–BIT Tx COUNTER

DIVDE RATIO

Din

16–BIT Rx COUNTER

DIVIDE RATIO

CLK

LAST

CLOCK

ENB

NOTE: ENB must be low during the serial transfer.

Figure 15. Programming Format for Transmit and Receive Counters

(4–Pin Interfacing Scheme)

Table 3. Global CT–1 Reference Frequency Setting vs Channel Frequencies

Country

Channels Frequency

fR1

fR2

U.S.A.

46/49 MHz (10, 15, 25 Channels)

5.0 kHz

—

France

26/41 MHz

6.25 kHz/12.5 kHz

—

Spain

31/41 MHz

5.0 kHz

—

Australia

30/39 MHz

5.0 kHz

—

U.K.

1.7/47 MHz

6.25 kHz

1.0 kHz

New Zealand

1.7/34/40 MHz

6.25 kHz

1.0 kHz

REFERENCE FREQUENCY SELECTION

AND PROGRAMMING

Figure 16 shows the bit function of the reference frequency

programming word. The user can either select the “fixed” ref-

erence frequency for all channels accordingly or provide a spe-

cific reference frequency for a particular channel by using two

reference frequency counters (e.g., for an application in

France, the base set transmit channel common fixed reference

frequency is 6.25 kHz or 12.5 kHz). (See Table 3 and Figure 6

for reference frequencies for various countries.) However,

transmit channels 6, 8, and 14 can be set to 25 kHz, and chan-

nel 8 reference frequency can be set to 50 kHz. But this refer-

ence frequency may not be applied to the receiving side; there-

fore, the receiving side reference frequency must be generated

by another reference frequency counter. The higher the refer-

ence frequency, the better the phase noise performance and

faster the lock time, but the PLL consumes more current if

both reference frequency counters are in operation.

In general, the 12–bit reference frequency counter plus the ÷ 4

and ÷ 25 module can offer all the reference frequencies for

global CT–1 transmit and receive channel requirements. Users

can select their own reference frequency by introducing the

additional 14–bit auxiliary reference frequency counter.

Again, the 14–bit auxiliary reference frequency counter can

be shut down by the auxiliary reference enable bit in the refer-

ence counter programming word by setting the bit to 0. At this

state, the fR2 is automatically connected to point C (the ÷25

block output), and fR1 can be connected to point A or B by

setting the fR1–S1 and fR1–S2 bits in the reference counter

program word. The 14–bit auxiliary reference frequency count-

er data will be in “Don’t Care” state.

If the 14–bit auxiliary reference frequency counter is enabled

(auxiliary reference enable = 1), then fR2 is automatically con-

nected to point D (14–bit counter output), and fR1 can be

selected to connect to point A, B, or C, depending on the bit

setting of fR1–S1 and fR1–S2. Table 4 and Figure 16 describe

the functions of the auxiliary reference enable bit and the

fR1–S1 and fR1–S2 bits selection.

Page 11 of 24

www.lansdale.com

Issue 0

Share Link: