Preliminary
HT9015
PLL
erence frequency for the receiver (RX) and
transmitter (TX) loops.
The figure below shows a simplified block dia-
gram of the programmable universal dual
phase-locked loop (PLL). It provides accurate
channel frequencies for cordless phone.
This dual PLL is fully programmable through
the mC serial interface and supports most coun-
try channel frequencies including USA, Spain,
Australia, Korea, New Zealand, U.K., Nether-
lands, France, Taiwan, and China.
The PLL contains one 14-bit programmable
counter, one phase detector, charge pump, un-
lock detector and the 2nd local oscillator. The
12-bit programmable counter provides the ref-
V
C
O
_
C
O
N
T
R
X
_
V
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V
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1
V
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2
1
4
-
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u
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h
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h
a
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(
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)
c
t
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(
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)
L
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2
1
1
2
-
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i
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F
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h
a
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(
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c
t
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(
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)
1
4
-
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Figure 9 PLL block diagram
19
April 10, 2000
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
