AM/FM TUNER FOR CAR RADIO AND HI-FI APPLICATIONS
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TDA7421N
August 2000
This is preliminary information on a new product now in development or undergoing evaluation. Details are subject to change without notice.
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HIGH PERFORMANCE FRONT-END IC FOR
AM/FM RECEIVERS
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FULLY INTEGRATED HIGH-SPEED PLL FOR
OPTIMIZED RDS APPLICATIONS
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FM MPX/AM AUDIO OUTPUT, 450kHz AM IF
OUTPUT FOR STEREO AM APPLICATIONS
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AM DOUBLE CONVERSION ARCHITECTURE
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AM/FM STATION DETECTOR AND DIGITAL
IF-COUNTER
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SINGLE FREQUENCY REFERENCE FOR
BOTH AM AND FM
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FULL ELECTRICAL ADJUSTMENT
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I
2
C-BUS PROGRAMMABLE
DESCRIPTION
The TDA7421N is a high-performance tuner circuit
which integrates AM and FM sections, PLL frequency
sinthesizer and IF counter on a single chip.
Use of BICMOS technology allows the implementa-
tion of tuning functions with a minimum of external
components.Value spread of external components
can be fully compensated by means of on-chip elec-
trical adjustment controlled by external
P.
The FM quality detection circuit, in conjunction with
the digital IF counter, enables the stop-station func-
tion in "seek" mode and MPX mute during reception.
The combination of programmable level detector and
IF counter allows reliable AM stop-station perfor-
mance.
The Automatic Gain Control (AGC) operates on dif-
ferent signal bandwidths in order to optimize sensitiv-
ity and dynamic range.
I
2
C-bus controls functions such as AGC, amplifier
gains, PLL and counter settings.
TQFP64
ORDERING NUMBER: TDA7421N
PRELIMINARY DATA
AM/FM TUNER FOR CAR RADIO AND HI-FI APPLICATIONS
PIN CONNECTIONS
1
2
3
5
6
4
7
8
9
10
27
11
28 29 30 31 32
59 58 57 56
54
55
53 52 51 50 49
43
42
41
39
38
40
48
47
46
44
45
FM AGC OUT
FM RF AGC IN
FM MIX IN +
AM MIX1 IN +
AM MIX1 IN -
FM MIX IN -
XTAL D
OSC GND
VCO E
RF GND
VCO B
PLL GND
SLEEP
SDA
SCL
DIG GND
DIG VDD
IFC SSTOP AM
STEREO OUT
CLN GND
IF2 GND
AM AGC2 TC
AM DET
FM IF AGC IN
AM MIX2 IN +
AM MIX2 IN-
RF VCC
AM SMETER TC
AM MIX2 OUT
FM IF AMP1 IN +
FM IF AMP1 IN -
FM IF AMP1 OUT
FM IF AMP2 IN +
FM IF AMP2 IN -
FM BW TC
FM MUTE DRIVE
FM SMETER AM SMETER
FM DET ADJ
FM QUAD+
FM SD AM SD
FM IF AMP2 OUT
IF1 VCC
FM LIM IN +
IF1 GND
FM LIM IN -
D98AU909
22 23 24 25 26
60
MIX OUT -
61
MIX OUT +
62
AM AGC1 TC
63
AM AGC1 RF AMP
64
AM AGC1 PIN
LP OUT
LP IN1
LP IN2
LP IN3
PLL VREF
17 18 19 20 21
37
36
34
33
35
FM QUAD-
IF2 VCC
AM REF
AM BPF
AM IF2 IN
12
13
14
15
16
PLL VCC
FM RF ADJ
FM ANT ADJ
XTAL G
OSC VCC
AUDIO OUT
TDA7421N
2/38
BLOCK DIAGRAM
AM RF AGC
AM MIX
IN+
AM MIX IN-
AGC1 ANT
AM AGC1 RF AMP OUT
AM
AGCI TC
AM
MIX2 IN+
AM MIX2
IN-
AM MIX2
OUT-
AM
DETECTOR
AM IF
AGC
AM IF2
IN
AM
IFREF
AM BPF
AM IF
COUNTER
AM DET
AM AGC2
TC
I
2
C
BUS
SDA
SCL
D99AU1042
FILTER
ADJ.
SLEEP
FILTER
ADJ.
FM
AGC
FILTER
ADJ.
FM MIX
IN+
FM MIX
IN-
VCOE
VCOB
XTALG
XTALD
FM AGC OUT
FM RF AGC IN
MIX OUT-
MIX OUT+
FM IF
AMP1 IN-
FM IF
AMP1 IN+
FM IF
AMP1 OUT
PHASE
COMPARATOR
FM IF
AMP2 IN+
FM IF
AMP2 OUT
CHARGE
PUMP
-
LIM IN-
TRIPLE
OUT
AM
SMETER
AM IF
IFC SSTOP
AM STEREO OUT
LPIN2
LPIN1
LPIN3
LPOUT
PLL V
CC
PLL VREF
PLL GND
-
+
FM IF
AGC IN
FM IF
AMP2 IN-
LIM IN+
FM IF
COUNTER
QUADRATURE
DETECTOR
AM
QUAD+
QUAD-
SLIDER
DETUNING
DETECTOR
S METER
ADJACENT
CH. DET.
ADJACENT
CH. MUTE
STOP
STATION
DETUNING
MUTE
SOFT
MUTE
FM MUTE
+
4 BIT DAC
+
4 BIT DAC
FM RF ADJ
FM ANT ADJ
AUDIO OUT
AM SMETER
FM SMETER
FM DET ADJ OUT
AM SD/
FM SD
BW TC
LIMITER
AM IF
COUNT
AM SD
FM SD
VCO
10.25MHz
OSC
LOCK
DET
FM
SMETER
AM SMETER TC
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TDA7421N
ABSOLUTE MAXIMUM RATINGS
THERMAL DATA
PIN DESCRIPTION
Symbol
Parameter
Value
Unit
T
amb
Operating Temperature Range
-40 to 85
C
T
stg
Storage Temperature Range
-55 to 150
C
V
CC
Analog Supply Voltages (PLL, RF, IF1, IF2, OSC)
10.2
V
V
DD
Digital Supply Voltage
5.5
V
Symbol
Parameter
Typ. Value
Unit
R
th j-amb, fa
Thermal Resistance Junction-Ambient, Free Air
68
C/W
R
th j-amb, sol
Thermal Resistance Junction-Ambient, Soldered
55
C/W
N.
Name
Function
1
AM MIX1 IN -
AM 1
st
mixer negative input (differential -)
2
AM MIX1 IN +
AM 1
st
mixer positive input (differential +)
3
FM MIX1 IN -
FM mixer negative input (differential -)
4
FM MIX1 IN +
FM mixer positive input (differential +)
5
FM RF AGC IN
RF AGC input
6
FM AGC OUT
FM AGC output voltage
7
RF GND
RF ground
8
VCO B
Local oscillator input to the transistor base
9
VCO E
Local oscillator input to the transistor emitter
10
OSC GND
Oscillator ground
11
XTAL D
Crystal oscillator MOS amplifier output
12
XTAL G
Crystal oscillator MOS amplifier input
13
OSC VCC
Oscillator positive supply
14
FM ANT ADJ
Tuning varicap voltage for antenna FM filter
15
FM RF ADJ
Tuning varicap voltage for RF FM filter
16
PLL VCC
PLL positive supply
17
LP OUT
Op Amp output to PLL loop filters
18
LP IN1
FM loop filter connection to op-amp inverting input
19
LP IN2
AM loop filter connection to op-amp inverting input
TDA7421N
4/38
20
LP IN3
FM-HS loop filter connection to op-amp inverting input
21
PLL VREF
Voltage reference to Op Amp noninverting input
22
PLL GND
PLL ground
23
SLEEP
I
2
C bus disconnect signal
24
SDA
I
2
C bus data
25
SCL
I
2
C bus clock
26
DIG VDD
Digital positive supply
27
DIG GND
Digital ground
28 (*)
IFC SSTOP
AM STEREO OUT
IF-Counter stop signal or
AM IF2 amplifier output
29
CLN GND
"Clean" ground
30
IF2 GND
IF2 ground
31
AM AGC2 TC
AM 2
nd
AGC time constant
32
AM DET
AM detector capacitor
33
AM BPF
AM IF filter
34
AM REF
Reference voltage of AM IF amplifier
35
AM IF2 in
AM IF2 amplifier input
36
IF2 VCC
IF2 positive supply
37
FM QUAD -
FM quadrature detector tank (differential -)
38
FM QUAD +
FM quadrature detector tank (differential +)
39
AUDIO OUT
FM MPX/AM Audio output
40 (*)
FM SD
AM SD
FM station detector output or
AM station detector output
41 (*)
FM SMETER
AM SMETER
FM DET ADJ
FM S-meter output or
AM S-meter output or
FM detector adjustment output
42
FM MUTE DRIVE
FM mute time constant
43
FM BW TC
FM detuning detector time constant
44
IF1 GND
IF1 ground
45
FM LIM IN -
FM limiter negative input (differential -)
46
FM LIM IN +
FM limiter negative input (differential +)
47
IF1 VCC
IF1 positive supply
48
FM IF AMP2 OUT
FM 2
nd
IF amplifier output
N.
Name
Function
PIN DESCRIPTION (Continued)
5/38
TDA7421N
(*) Pin function is user defined by software.
49
FM IF AMP2 IN -
FM 2
nd
IF amplifier negative input (differential -)
50
FM IF AMP2 IN +
FM 2
nd
IF amplifier positive input (differential +)
51
FM IF AMP1 OUT
FM 1
st
IF amplifier output
52
FM IF AMP IN -
FM 1
st
IF amplifier negative input (differential -)
53
FM IF AMP IN +
FM 1
st
IF amplifier positive input (differential +)
54
AM S-METER TC
AM S-meter time constant
55
AM MIX2 OUT
AM 2
nd
mixer output
56
RF VCC
RF positive supply
57
AM MIX2 IN -
AM 2nd mixer negative input (differential -)
58
AM MIX2 IN +
AM 2nd mixer positive input (differential +)
59
FM IF AGC IN
FM IF AGC input
60
MIX OUT -
FM/AM 1
st
mixer negative output (differential -)
61
MIX OUT +
FM/AM 1
st
mixer positive output (differential +)
62
AM AGC1 TC
AM 1
st
AGC time constant
63
AM AGC1 RF AMP
AM 1
st
AGC voltage output (to RF amplifier)
64
AM AGC1 PIN
AM 1
st
AGC current output (to antenna attenuation diodes)
N.
Name
Function
PIN DESCRIPTION (Continued)
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