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

2/7

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