LC72133M(1999) Просмотр технического описания (PDF) - SANYO -> Panasonic

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Компоненты Описание

производитель

LC72133M
(Rev.:1999)

PLL Frequency Synthesizer for Electronic Tuning

SANYO -> Panasonic 

LC72133M, 72133V

2. Unlock Detection Software

CE

Data input

N

Old data

New data

Data output ➀ Data output ➁

VCO

frequency

øERROR

Unlock (UL) serial

data input

Unlock detection

pin output

Locked

Unlocked

Locked

Figure 3

A11938

3. Unlocked State Data Output Using Serial Data Output

In the LC72133, once an unlocked state occurs, the unlocked state serial data (UL) will not be reset until a data input

(or output) operation is performed. At the data output ① point in Figure 3, although the VCO frequency has

stabilized (locked), since no data output has been performed since the divisor N was changed the unlocked state data

remains in the unlocked state. As a result, even though the frequency has stabilized (locked), the system remains

(from the standpoint of the data) in the unlocked state.

Therefore, the unlocked state data acquired at data output ①, which occurs immediately after the divisor N was

changed, should be treated as a dummy data output and ignored. The second data output (data output ➁) and

following outputs are valid data.

Divisor N modification

(data input)

...............

Wait for at least two reference

frequency periods.

Dummy data output

Valid data output

...............

Valid data can be output at intervals

of one reference frequency period or

longer

Locked?

*

NO

YES

Note: Locking state determination is more

reliable if it is based on reading valid

output data several times.

Locked State Determination Flowchart

4. Directly Outputting Unlocked State Data from the DO Pin (Set by the DO pin control data)

Since the locking state (high = locked, low = unlocked) is output directly from the DO pin, the dummy data

processing described in section 3 above is not required. After changing the divisor N, the locking state can be

checked after waiting at least two reference frequency periods.

No. 5427-19/23

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