TDA7479
SINGLE CHIP RDS DEMODULATOR + FILTER
1
■
FEATURES
VERY HIGH RDS DEMODULATION QUALITY
WITH IMPROVED DIGITAL SIGNAL
PROCESSING
HIGH PERFORMANCE, 57KHz BANDPASS
FILTER (8th ORDER)
FILTER ADJUSTMENT FREE AND WITHOUT
EXTERNAL COMPONENTS
PURELY DIGITAL RDS DEMODULATION
WITHOUT EXTERNAL COMPONENTS
ARI (SK INDICATION) AND RDS SIGNAL
QUALITY OUTPUT
4.332MHz CRYSTAL OSCILLATOR(8.664 and
17.328MHz OPTIONAL)
LOW NOISE CMOS TECHNOLOGY
LOW RADIATION
Figure 1. Packages
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■
■
■
■
■
■
SO16
TSSOP16
Table 1. Order Codes
Part Number
TDA7479D
TDA7479AD
Package
SO16
TSSOP16
EBU (European Broadcasting Union) specifications.
The device is made up of two sections: a cascaded
antialiasing + switched capacitors 8
th
bandpass filter
for precise RDS band selection and a demodulating
section that performs the extraction od RDS data
stream (RDDA) and clock (RDCL), to be further pro-
cessed by a suitable RDS decoder.
Outputs for RDS signal quality and ARI indication are
also present.
2
DESCRIPTION
The TDA7479 recovers the additional inaudible RDS
information which is transmitted by FM radio broad-
casting stations and operates in accordance with the
Figure 2. Block Diagram
C1 27pF
4.332MHz
C2 47pF
T57
15
4
270pF
2nd ORDER
ANTIALIASING
FILTER
OSCIN
13
OSCOUT
14
MPX
5
OSCILLATOR &
DIVIDER
9
OSEL
FSEL
16
FILOUT
8
8th ORDER
SC-BANDPASS
FILTER
57KHz PLL
1187.5Hz
PLL
7
1
V
S
100nF
VREF
10
µ
F
INTEGRAL
BIPHASE DEC.
3
-
+
POLARITY
BIPHASE DEC.
0
1
2
12
FAST ARI
INDICATOR
QUAL DET.
RDCL
ARI
QUAL
MUX
DIFF. DECODER
RDDA
10
TEST LOGIC
TM
6
GND
11
EXTRES
D97AU751A
December 2004
Rev. 6
1/8
TDA7479
Table 2. Pin Description
No pin
1
2
3
4
5
Name
QUAL
RDDA
VREF
MPX
OSEL
RDS data output
Reference voltage
RDS input signal
Oscillator selector pin:
- open, closed to V
S
= quartz oscillator
- closed to GND=external driven
Ground
Output for ARI indication:
- high when RDS+ARI are present
- high when only ARI is present
- low when only RDS is present
- undefined when nos signal is present
Filter output
Frequency selector pin:
-100K to V
S
= 17.328MHz
- open = 4.332MHz
- closed to VS = 8.664MHz
Test mode pin: - open = normal operation - closed to VS = testmode
Reset pin: - open=run mode - closed to VS = reset condition
Supply voltage
Oscillator input
Oscillator output
Testing output pin: 57kHz clock output
RDS clock output 1187.5Hz
Description
Output for signal quality indication (High = good)
6
7
GND
ARI
8
9
FILOUT
FSEL
10
11
12
13
14
15
16
TM
EXTRES
V
S
OSCIN
OSCOUT
T57
RDCL
Figure 3. Pin Connection
(Top view)
QUAL
RDDA
VREF
MPX
OSEL
GND
ARI
FILOUT
1
2
3
4
5
6
7
8
D97AU752
16
15
14
13
12
11
10
9
RDCL
T57
OSCOUT
OSCIN
V
S
EXTRES
TM
FSEL
Table 3. Thermal Data
Symbol
R
th j-case
Description
Thermal Resistance Junction-case Max.
SO16
200
TSSOP16
160
Unit
°C/W
2/8
TDA7479
Table 4. Absolute Maximum Ratings
Symbol
V
S
T
op
T
stg
Supply Voltage
Operating Temperature Range
Storage Temperature
Parameter
Value
-0.3 to 7
-40 to 85
-55 to 150
Unit
V
°C
°C
Table 5. Electrical Characteristcs
(T
amb
= 25°C, V
S
= 5V, unless otherwise specified)
Symbol
V
S
I
S
FILTER
f
C
BW
G
A
Center frequency
3dB Bandwidth
Gain
Attenuation
f = 57kHz
∆f
± 4kHz
f = 38kHz
f = 67kHz
R
I
R
L
S/N
V
IN
S
RDS
S
ARI
V
REF
Input impedance of MPX
Load impedance on FILOUT
Signal to noise ratio
MPX input signal
RDS Detection Sensitivity
ARI Detection Sensitivity
Reference
V
IN
= 3mVRMS
f = 19kHz; T3
≤
40dB
(1)
f = 57kHz (RDS+ ARI)
1
3
V
S
/2
56.5
2.5
18
18
50
35
80
1
30
40
1000
50
57
3
20
22
60
45
120
150
57.5
3.5
22
kHz
kHz
dB
dB
dB
dB
KΩ
MΩ
dB
mV
RMS
mV
RMS
mVrms
mVrms
V
Parameter
Supply voltage
Supply current
Test Condition
Min.
4.5
Typ.
5
7.5
Max.
5.5
11.0
Unit
V
mA
DEMODULATOR
Input pins (EXTRES, FSEL, TM)
Input pin (OSEL)
I
PD
I
PU
V
IH
VIL
V
OH
V
OL
VCLL
VCLH
V
PP
Input Current
Input Current
Input voltage high
Input voltage low
Ouput voltage high
Output voltage low
Input level OSCIN pin
Input level OSCIN pin
Amplitude OSCOUT
Amplitude OSCIN
(for external drive)
I
L
= 0.5mA
I
L
= 0.5mA
OSEL = open circuit
OSEL = open circuit
OSEL = open circuit
OSEL = GND, f = 4.332MHz
OSEL = GND, f = 8.664MHz
OSEL = GND, f = 17.328MHz
(1) The 3rd harmonic (57kHz) must be less than -40dB with respect to the input signal plus gain.
all with internal pull down resistor
with internal pull up resistor
V
IN
= 5V (pull-down input)
V
IN
= 0V (pull-up input)
15
-25
0.7 · V
S
0.8 · V
S
0.2 · V
S
0.3 · V
S
4
4.6
0.4
1
1
4
4.5
100
120
150
30
-10
µA
µA
V
V
V
V
V
V
V
mVpp
mVpp
mVpp
Output pins (RDCL, RDDA, ARI, QUAL, T57)
OSCILLATOR
3/8
TDA7479
Figure 4. RDS timing diagram
CLOCK
LINE
DATA
LINE
3
OUTPUT TIMING
The RDS (1187.5Hz) output clock on RDCL line is synchronized to the incoming data. According to the internal
PLL lock condition data change can result on the falling or on the rising clock edge. (see Fig. 4)Whichever clock
edge is used by the decoder (rising or falling edge) the data will remain valid for 416.7
µs
after the clock transi-
tion.
4
OSCILLATOR CONTROLS (FSEL, OSEL)
Three different crystal frequencies can be used. The adaption of the internal clock divider to the external crystal
is achieved via the input pin FSEL. See the following table for reference:
Table 6.
Crystal
4.332MHz
8.664MHz
17.328MHz
FSEL (pin configuration)
connected to GND or openconnected to Vs external resistor of 100K to Vs
A special mode is introduced to reduce EMI. With pin OSEL connected to GND the internal oscillator is switched
off and an external sinusoidal frequency could be applied on OSCIN. The peak to peak voltage of this signal
can be reduced down to 60mV.
In this mode the frequency selection via FSEL is still active.
Suggested values of C1 and C2 are shown in the following table:
Table 7.
Crystal
4.332MHz
8.664MHz
17.328MHz
C1
27pF
27pF
27pF
C2
47pF
-
-
4/8
TDA7479
Figure 5. SO16 Mechanical Data & Package Dimensions
mm
DIM.
MIN.
A
A1
B
C
D
(1)
E
e
H
h
L
k
ddd
10.0
0.25
0.40
2.35
0.10
0.33
0.23
10.10
7.40
1.27
10.65
0.75
1.27
0.394
0.010
0.016
TYP.
MAX.
2.65
0.30
0.51
0.32
10.50
7.60
MIN.
0.093
0.004
0.013
0.009
0.398
0.291
0.050
0.419
0.030
0.050
TYP.
MAX.
0.104
0.012
0.200
0.013
0.413
0.299
inch
OUTLINE AND
MECHANICAL DATA
0˚ (min.), 8˚ (max.)
0.10
0.004
(1) “D” dimension does not include mold flash, protusions or gate
burrs. Mold flash, protusions or gate burrs shall not exceed
0.15mm per side.
SO16 (Wide)
0016021 C
5/8
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