廬
TDA7427A
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 SIX OUT-
PUTS FOR FLEXIBILITY IN APPLICATION
FULLY PROGRAMMABLE BY I
2
C BUS
DESCRIPTION
The TDA7427A is a PLL frequency synthesizer
BLOCK DIAGRAM
TSSOP28
SO28
ORDERING NUMBERS:
TDA7427AAD (TSSOP28)
TDA7427AAD1 (SO28)
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.
SWITCH
OUT
FM_IN
24
PRECOUNTER
:32/33
HFREF
19
SWITCH
AM/FM
SWITCH
SWM/DIR
SWITCH
SWM/DIR
PHASE
COMP
CHARGE
PUMP
-
+
VDD1
5 BIT PROG.
COUNTER
INLOCK
DETECTOR
17
DOUT1/INLOCK
2
3
SWITCH
LP1/LP2
1
LP_HC
LP_AM
LP_FM
AM_IN
25
28
LP_OUT
11 BIT PROG
COUNTER
OSCIN
OSCOUT
9
10
REF
OSCILLATOR
16 BIT PROG
COUNTER
4
VREF
ADDR
SCL
SDA
20
12
13
I2C BUS
INTERFACE
26
GNDAN
VDD2
VDD1
GNDDIG
IF_AM
27
21
22
14
SWITCH
AM/FM
11-21 BIT PROG COUNTER
PORT EXTENSION
SUPPLY
&
POWER-ON
RESET
14 BIT PROG
COUNTER
TIMER
CONTROL
TEST
LOGIC
IF_FM
15
16
D95AU372D
18
DOUT2
5
DOUT3
6
DOUT4
7
DOUT5
8
DOUT6
SSTOP
July 1998
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