LC72140M Ver la hoja de datos (PDF) - SANYO -> Panasonic
Número de pieza
componentes Descripción
Fabricante
LC72140M Datasheet PDF : 15 Pages
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LC72140, 72140M
When unlock is detected following a channel change, PDS (the sub-charge pump) operates. The value of R1 changes to
R1M||R1S (R1S≅500Ω), as shown in Figure 14, decreasing the low-pass filter time-constant and accelerating PLL lock-
ing.
Figure 14. Charge pump connections
The local oscillator signal is divided by N. When the frequency of the divided signal is higher than the reference fre-
quency, PD0 and PD1 are HIGH, and when lower, they are LOW. Both outputs are floating when the two signals are
equal in frequency.
Pin States After Power-ON Reset
The state of the input/output ports after power-ON reset is shown in Table 16.
Table 16. Power-ON reset states
Pin
Reset state
Pin type
I/O1
I1
Open-drain
I/O2
I2
Open-drain
I/O3
I3
Open-drain
I/O4
I4
CMOS
I/O5
I5
CMOS
O6
O6
CMOS
O7
O7
CMOS
HCTR/I6
I6
LCTR/I7
I7
Notes
1. Phase comparator control
Modes DZA and DZB do not have insensitive bands (dead zones) and, therefore, the charge pump operates continu-
ously. Consequently, measures should be taken to ensure reference freqeuncy sidebands do not occur.
Modes DZC and DZD do have insensitive bands. Consequently, measures should be taken to ensure phase noise is not
generated.
2. FMIN, AMIN, HCTR and LCTR
These inputs should each be capacitively coupled using a 50 to 100pF capacitor. Also, these capacitors should be
mounted as close as possible to their respective inputs.
3. IF counting using HCTR or LCTR
The LC72140 and LC72140M can perform IF count tuning when connected to an SD (station detector) signal from an
IF IC. IF counting should start when the SD signal becomes active.
4. Using the general-purpose counter
In IF count mode, the IF IC’s SD (station detector) signal presence is determined by the microcontroller and if an SD
signal is present, the IF count buffer output turns ON and IF count becomes active. During auto-search in IF count
only, there is a possibility of the count stopping even when there is no station present due to the IF count buffer output
leakage.
No.4464–14/15
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