SGS Thomson Microelectronics TDA7331D, TDA7331 Datasheet

SINGLE CHIP RDS DEMODULATOR + FILTER

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

DIP20 SO20

ORDERING NUMBERS:

TDA7331 TDA7331D

DESCRIPTION

The TDA7331, an improved version of
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

GND N.C.

6,7,8,17

EXTRES

20

D97AU686B

1/7

TDA7331

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

V

T

op

T

stg

PIN FUNCTION

Nopin Name Functional description

1 MPX RDS inputsignal
2 VREF Reference voltage
3 OSEL Oscillator selector pin: - open, or closed to Vs = quartz oscillator

4 FILOUT Filter output
5 GND Ground

6 nc Not connected

7 nc Not connected
8 nc Not connected

9 OSCOUT Oscillator output
10 OSCIN Oscillator input
11 T57 Testing output pin: 57kHz clock output
12 RDCL RDS clock output 1187.5Hz
13 RDDA RDS dataoutput
14 QUAL Output for signal quality indication (High = good)
15 ARI Output for ARI indication: - high whenRDS+ARI arepresent

16 Vs Supply voltage
17 nc Not connected
18 FSEL Frequency selector pin: - 100K to V

19 TM Test mode pin: - open = normal operation

20 EXTRES Reset pin: - open = run mode

Supply Voltage 7 V

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

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MPX
VREF
OSEL

FILOUT

GND

N.C.
N.C.
N.C.

OSCOUT

1
2
3
4
5
6
7
8
9 RDCL

OSCIN 10 T5711

D97AU687

19
18
17
16
15
14
13
12

EXTRES20
TM
FSEL
N.C.
V

S

ARI
QUAL
RDDA

TDA7331

THERMAL DATA

Symbol Description DIP20 SO20 Unit

R

th j-amb

Thermal Resistance Junction-Ambient Max 100 200

C/W

°

ELECTRICALCHARACTERISTICS (T

=25°C, VS=5V, unlessotherwisespecified).

amb

Symbol Parameter Test Condition Min. Typ. Max. Unit

V

S

I

S

Supply voltage 4.5 5 5.5 V
Supply current 7.5 11.0 mA

FILTER

f

C

BW 3dBBandwidth 2.5 3 3.5 kHz

G Gain f = 57kHz 18 20 22 dB

A Attenuation

R

R

L

S/N Signal to noise ratio V

V

IN

V

REF

Center frequency 56.5 57 57.5 kHz

4kHz 18 22 dB

∆f±

f = 38kHz 50 60 dB
f = 67kHz 35 45 dB

Input impedance of MPX 80 120 150 K

I

Load impedance on FILOUT 1 M

=3mV

IN

RMS

30 40 dB

MPX input signal f = 19kHz; T3 ≤ 40dB(1)

f = 57kHz (RDS+ ARI)

Reference VS/2 V

100050mV

mV

DEMODULATOR

Input pins (EXTRES, FSEL, TM) all with internal pull down resistor
Input pin (OSEL) with internal pull up resistor

I

PD

I

PU

V

IH

V

IL

Input Current VIN= 5V (pull-down input) 15 30
Input Current VIN= 0V (pull-up input) -25 -10
Input voltage high 0.7⋅VS0.8⋅V

S

Input voltage low 0.2 ⋅ VS0.3⋅ V

S

Output pins (RDCL, RDDA, ARI, QUAL, T57)

V

OH

V

OL

Ouput voltage high IL= 0.5mA 4 4.6 V
Output voltage low IL= 0.5mA 0.4 1 V

OSCILLATOR

VCLL Input level OSCIN pin OSEL= open circuit 1 V

VCLH Input level OSCIN pin OSEL= open circuit 4 V

Amplitude OSCOUT OSEL= open circuit 4.5 V

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

100 mVpp

120 mVpp

150 mVpp

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:

Crystal FSEL (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:

Crystal C1 C2

4.332MHz

8.664MHz

17.328MHz

27pF
27pF
27pF

47pF

-

-

4/7

DIP20 PACKAGE MECHANICAL DATA

TDA7331

DIM.

MIN. TYP. MAX. MIN. TYP. MAX.

a1 0.254 0.010

B 1.39 1.65 0.055 0.065

b 0.45 0.018

b1 0.25 0.010

D 25.4 1.000
E 8.5 0.335

e 2.54 0.100

e3 22.86 0.900

F 7.1 0.280

I 3.93 0.155

L 3.3 0.130

Z 1.34 0.053

mm inch

5/7

TDA7331

SO20 PACKAGEMECHANICAL DATA

DIM.

MIN. TYP. MAX. MIN. TYP. MAX.

A 2.65 0.104
a1 0.1 0.3 0.004 0.012
a2 2.45 0.096

b 0.35 0.49 0.014 0.019

b1 0.23 0.32 0.009 0.013

C 0.5 0.020
c1 45 (typ.)

D 12.6 13.0 0.496 0.512

E 10 10.65 0.394 0.419

e 1.27 0.050

e3 11.43 0.450

F 7.4 7.6 0.291 0.299

L 0.5 1.27 0.020 0.050

M 0.75 0.030

S 8 (max.)

mm inch

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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

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