廬
TDA7427
AM-FM RADIO FREQUENCY SYNTHESIZER
AND IF COUNTER
ON-CHIP REFERENCE OSCILLATOR AND
PROGRAMMABLE IF COUNTER
VHF INPUT AND PRECOUNTER FOR FRE-
QUENCIES UP TO 290MHz (SUITABLE FOR
DAB APPLICATION)
HF INPUT FOR FREQUENCIES UP TO
64MHz (SHORT WAVE BAND)
IN-LOCK DETECTOR FOR SEARCH/STOP
STATION FUNCTION
STAND-BY MODE FOR LOW POWER CON-
SUMPTION
HIGH CURRENT SOURCE FOR 0.5ms
LOCK-IN TIME
DIGITAL PORT EXTENSION WITH TWO
OUTPUTS FOR FLEXIBILITY IN APPLICA-
TION
FULLY PROGRAMMABLE BY I
2
C BUS
DESCRIPTION
The TDA7427 is a PLL frequency synthesizer
BLOCK DIAGRAM
DIP20
SO20
ORDERING NUMBERS:
TDA7427(DIP20)
TDA7427D (SO20)
with an additional IF counting system that per-
forms all the functions needed in a complete PLL
radio tuning system for conventional and high
speed RDS tuners. The device has dedicated out-
puts for IN-LOCK detection and Search/Stop sta-
tion.
13
FM_IN
16
SWITCH
AM/FM
HFREF
14
SWITCH
SWM/DIR
SWITCH
SWM/DIR
PHASE
COMP
CHARGE
PUMP
-
+
VDD1
20
PRECOUNTER
:32/33
5 BIT PROG.
CNT
INLOCK
DETECTOR
2
3
SWITCH
LP1/LP2
1
DOUT1/INLOCK
LP_HC
LP_AM
LP_FM
AM_IN
17
LPOUT
11 BIT PROG
CNT
OSCIN
OSCOUT
5
6
REF
OSCILLATOR
16 BIT PROG
CNT
4
VREF
SCL
SDA
8
9
I2C BUS
INTERFACE
18
GNDan/GNDdig
VDD2
VDD1
19
15
14 BIT PROG
CNT
TIMER
CONTROL
TEST
LOGIC
POWER ON
RESET
IF_AM
10
11-21 BIT PROG CNT
PORT EXTENSION
IF_FM
11
12
D95AU418B
7
DOUT3
SSTOP
November 1999
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