VERYHIGH RDS DEMODULATION QUALITY
WITH IMPROVED DIGITAL SIGNAL PROCESSING
HIGH PERFORMANCE, 57KHz BANDPASS
FILTER (8th ORDER)
PURELY DIGITAL RDS DEMODULATION
WITHOUTEXTERNAL COMPONENTS
ARI INDICATION AND RDS SIGNAL QUALITY OUTPUTS
4.332MHzCRYSTALOSCILLATOR
(8.664 and 17.328MHz SELECTABLE OPTIONS)
LOW NOISE CMOS TECHNOLOGY
LOW RADIATION
TDA7331
DIP20SO20
ORDERING NUMBERS:
TDA7331TDA7331D
DESCRIPTION
TheTDA7331,animprovedversionof
TDA7330B, recovers the additional inaudible
RDS informationwhich is transmittedby FM radio
broadcasting stations and operates in accordance with the EBU (European Broadcasting Union) specifications.
The device is made up of two sections: a cas-
BLOCK DIAGRAM and TESTCIRCUIT
FILOUT
1
2nd ORDER
ANTIALIASING
FILTER
4
16
2VREF
8th ORDER
SC-BANDPASS
FILTER
-
+
MPX
V
S
100nF
10µF
270pF
caded antialiasing + switched capacitors bandpass filter for precise RDS band selection and a
demodulatingsection that performs the extraction
od RDS data stream (RDDA) and clock (RDCL),
to be furher processed by a suitable RDS decoder.
Outputs for RDS signal quality and ARI indication
are also present.
4.332MHz C2 47pFC1 27pF
T57
11
57KHz PLL
FAST
INDICATOR
POLARITY
BIPHASEDEC.
INTEGRAL
BIPHASEDEC.
OSCILLATOR
ARI
DIVIDER
OSCOUTOSCIN
910
3
&
1187.5Hz
PLL
QUAL DET.
0
MUX
1
DIFF. DECODER
TEST LOGIC
OSEL
18
FSEL
12
RDCL
15
ARI
14
QUAL
13
RDDA
19
TM
February 1998
5
GNDN.C.
6,7,8,17
EXTRES
20
D97AU686B
1/7
TDA7331
ABSOLUTE MAXIMUM RATINGS
SymbolParameterValueUnit
V
T
op
T
stg
PIN FUNCTION
NopinNameFunctional description
1MPXRDS inputsignal
2VREFReference voltage
3OSELOscillator selector pin: - open, or closed to Vs = quartz oscillator
4FILOUTFilter output
5GNDGround
6ncNot connected
7ncNot connected
8ncNot connected
9OSCOUTOscillator output
10OSCINOscillator input
11T57Testing output pin: 57kHz clock output
12RDCLRDS clock output 1187.5Hz
13RDDARDS dataoutput
14QUALOutput for signal quality indication (High = good)
15ARIOutput for ARI indication: - high whenRDS+ARI arepresent
16VsSupply voltage
17ncNot connected
18FSELFrequency selector pin: - 100K to V
19TMTest mode pin:- open = normal operation
20EXTRESReset pin: - open = run mode
Supply Voltage7V
S
Operating Temperature Range-40 to 85
Storage Temperature-55 to 150
- closed to GND = external driven
- high when only ARI is present
- low when only RDS is present
- undefined when nos signal is present
= 17.328MHz
S
S
= testmode
S
= 8.664MHz
- closed to V
-closed to V
- open = 4.332MHz
- closed to V
= reset condition
S
C
°
C
°
PIN CONNECTION
2/7
MPX
VREF
OSEL
FILOUT
GND
N.C.
N.C.
N.C.
OSCOUT
1
2
3
4
5
6
7
8
9RDCL
OSCIN10T5711
D97AU687
19
18
17
16
15
14
13
12
EXTRES20
TM
FSEL
N.C.
V
S
ARI
QUAL
RDDA
TDA7331
THERMAL DATA
SymbolDescriptionDIP20SO20Unit
R
th j-amb
Thermal Resistance Junction-AmbientMax100200
C/W
°
ELECTRICALCHARACTERISTICS (T
=25°C, VS=5V, unlessotherwisespecified).
amb
SymbolParameterTest ConditionMin.Typ.Max.Unit
V
S
I
S
Supply voltage4.555.5V
Supply current7.511.0mA
FILTER
f
C
BW3dBBandwidth2.533.5kHz
GGainf = 57kHz182022dB
AAttenuation
R
R
L
S/NSignal to noise ratioV
V
IN
V
REF
Center frequency56.55757.5kHz
4kHz1822dB
∆f±
f = 38kHz5060dB
f = 67kHz3545dB
Input impedance of MPX80120150K
I
Load impedance on FILOUT1M
=3mV
IN
RMS
3040dB
MPX input signalf = 19kHz; T3 ≤ 40dB(1)
f = 57kHz (RDS+ ARI)
ReferenceVS/2V
100050mV
mV
DEMODULATOR
Input pins (EXTRES, FSEL, TM)all with internal pull down resistor
Input pin (OSEL)with internal pull up resistor
Ouput voltage highIL= 0.5mA44.6V
Output voltage lowIL= 0.5mA0.41V
OSCILLATOR
VCLLInput level OSCIN pinOSEL= open circuit1V
VCLHInput level OSCIN pinOSEL= open circuit4V
Amplitude OSCOUTOSEL= open circuit4.5V
V
PP
Amplitude OSCIN
(for external drive)
(1) The 3rd harmonic (57kHz) must be less than -40dB with respect to the input signal plus gain.
OSEL = GND,
f = 4.332MHz
OSEL = GND,
f = 8.664MHz
OSEL = GND,
f = 17.328MHz
100mVpp
120mVpp
150mVpp
µ
µ
Ω
Ω
RMS
RMS
A
A
V
V
3/7
TDA7331
Figure 1. RDS timing diagram
CLOCK
LINE
DATA
LINE
OUTPUT TIMING
The RDS (1187.5Hz) output clock on RDCL line
is synchronizedto 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. 1)
Whichever clock edge is used by the decoder
(rising or falling edge) the data will remain valid
for 416.7 µsec after the clock transition.
OSCILLATORCONTROLS (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 followings table for reference:
CrystalFSEL (pin configuration)
4.332MHz
8.664MHz
17.328MHz
connected to GND or open
connected toVs
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.
Suggestedvalues of C1 and C2 are shown in the
followingtable:
CrystalC1C2
4.332MHz
8.664MHz
17.328MHz
27pF
27pF
27pF
47pF
-
-
4/7
DIP20 PACKAGE MECHANICAL DATA
TDA7331
DIM.
MIN.TYP.MAX.MIN.TYP.MAX.
a10.2540.010
B1.391.650.0550.065
b0.450.018
b10.250.010
D25.41.000
E8.50.335
e2.540.100
e322.860.900
F7.10.280
I3.930.155
L3.30.130
Z1.340.053
mminch
5/7
TDA7331
SO20 PACKAGEMECHANICAL DATA
DIM.
MIN.TYP.MAX.MIN.TYP.MAX.
A2.650.104
a10.10.30.0040.012
a22.450.096
b0.350.490.0140.019
b10.230.320.0090.013
C0.50.020
c145 (typ.)
D12.613.00.4960.512
E1010.650.3940.419
e1.270.050
e311.430.450
F7.47.60.2910.299
L0.51.270.0200.050
M0.750.030
S8 (max.)
mminch
6/7
TDA7331
Information furnished is believed to be accurate and reliable.However, SGS-THOMSON Microelectronicsassumes no responsibility for the
consequences of use of such information nor for any infringementof patentsor other rights of third parties which may result fromits use. No
license is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics. Specification mentioned in this publication are subject to change without notice.This publication supersedes and replaces all information previously supplied.
SGS-THOMSON Microelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of SGS-THOMSON Microelectronics.
1998 SGS-THOMSON Microelectronics – Printed in Italy – All RightsReserved
SGS-THOMSON Microelectronics GROUP OF COMPANIES
Australia - Brazil - Canada - China - France - Germany - Italy - Japan - Korea - Malaysia - Malta - Morocco - The Netherlands -
Singapore - Spain - Sweden - Switzerland- Taiwan - Thailand - United Kingdom - U.S.A.
7/7
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