ST TDA7479 User Manual

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Single chip RDS demodulator + filter

Features

■ Very high RDS demodulation quality with

improved digital signal processing

■ High performance, 57 kHz bandpass filter

order)

■ FIlter adjustment free and without external

components

■ Purely digitaL RDS Demodulation without

external components

■ ARI (SK indication) and RDS signal quality

output

■ 4.332 MHz crystal oscillator

(8.664 and 17.328 MHz optional)

■ Low noise CMOS technology

■ Low radiation

Description

The TDA7479 recovers the additional inaudible RDS information which is transmitted by FM radio broadcasting stations and operates in accordance with the EBU (European Broadcasting Union) specifications.

Table 1. Device summary

TDA7479

SO16

TSSOP16

The device is made up of two sections: a cascaded antialiasing + switched capacitors 8 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 processed by a suitable RDS decoder.

Outputs for RDS signal quality and ARI indication are also present.

Order code Package Packing

E-TDA7479D

E-TDA7479AD

1. Device in ECOPACK® package (see Section 5: Package information on page 9).

November 2008 Rev 7 1/12

(1)

SO16 Tube

TSSOP16 Tube

www.st.com

Contents TDA7479

Contents

1 Block diagram and pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.1 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.2 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2 Electrical specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.1 Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.2 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.3 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3 Output timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

4 Oscillator controls (FSEL, OSEL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

5 Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

6 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2/12

TDA7479 Block diagram and pin description

1 Block diagram and pin description

1.1 Block diagram

Figure 1. Block diagram

4.332MHz C2 47pFC1 27pF

MPX

100nF

10μF

270pF

FILOUT

3VREF

GND

2nd ORDER

ANTIALIASING

FILTER

8th ORDER

SC-BANDPASS

FILTER

1.2 Pin description

T57

57KHz PLL

FAST ARI

INDICATOR

POLARITY

BIPHASE DEC.

INTEGRAL

BIPHASE DEC.

OSCILLATOR &

DIVIDER

OSCOUTOSCIN

1413

OSEL

FSEL

1187.5Hz PLL

QUAL DET.

MUX

EXTRES

DIFF. DECODER

TEST LOGIC

D97AU751A

RDCL

ARI

QUAL

RDDA

Figure 2. Pin connection (top view)

QUAL

RDDA

VREF

MPX

OSEL

GND

ARI

FILOUT 8 FSEL9

7TM

D97AU752

RDCL16

T57

OSCOUT

OSCIN

EXTRES

3/12

Block diagram and pin description TDA7479

Table 2. Pin description

No pin Name Description

1 QUAL Output for signal quality indication (High = good)

2 RDDA RDS data output

3 VREF Reference voltage

4 MPX RDS input signal

Oscillator selector pin:

5 OSEL

6 GND Ground

7ARI

8 FILOUT Filter output

9 FSEL

10 TM

– open, closed to V

= quartz oscillator

– closed to GND = external driven

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

Frequency selector pin: – 100 kHz to VS = 17.328 MHz – open = 4.332MHz – closed to VS = 8.664 MHz

Test mode pin: – open = normal operation – closed to VS = test mode

Reset pin:

11 EXTRES

– open = run mode – -closed to VS = reset condition

12 V

Supply voltage

13 OSCIN Oscillator input

14 OSCOUT Oscillator output

15 T57 Testing output pin: 57 kHz clock output

16 RDCL RDS clock output 1187.5 Hz

4/12

TDA7479 Electrical specification

2 Electrical specification

2.1 Thermal data

Table 3. Thermal data

Symbol Parameter SO16 TSSOP16 Unit

th j-case

Thermal resistance junction to case Max. 200 160 °C/W

2.2 Absolute maximum ratings

Table 4. Absolute maximum ratings

Symbol Parameter Value Unit

Supply voltage -0.3 to 7 V

Operating temperature range -40 to 85 °C

Storage temperature -55 to 150 °C

stg

2.3 Electrical characteristics

Table 5. Electrical characteristics

Symbol Parameter Test condition Min. Typ. Max. Unit

Filter

= 25°C, VS = 5V, unless otherwise specified)

amb

Supply voltage 4.5 5 5.5 V

Supply current 7.5 11.0 mA

Center frequency 56.5 57 57.5 kHz

BW 3dB Bandwidth 2.5 3 3.5 kHz

G Gain f = 57 kHz 18 20 22 dB

Δf ± 4 kHz 18 22 dB

A Attenuation

f = 38 kHz 50 60 dB

f = 67 kHz 35 45 dB

Input impedance of MPX 80 120 150 KΩ

Load impedance on FILOUT 1 MΩ

S/N Signal to noise ratio V

MPX input signal

RDS detection sensitivity 1 mVrms

RDS

ARI Detection Sensitivity 3 mVrms

ARI

= 3 mVrms 30 40 dB

f = 19 kHz; T3 ≤ 40 dB

(1)

100050mV

f = 57 kHz (RDS+ ARI)

5/12

RMS

Electrical specification TDA7479

Table 5. Electrical characteristics (continued)

= 25°C, VS = 5V, unless otherwise specified)

amb

Symbol Parameter Test condition Min. Typ. Max. Unit

Reference VS/2 V

REF

Demodulator

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

Input current VIN = 5 V (pull-down input) 15 30 μA

Input current VIN = 0 V (pull-up input) -25 -10 μA

Input voltage high

Input voltage low

0.7 · VS0.8 · V

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

Output voltage high IL = 0.5mA 4 4.6 V

Output voltage low IL = 0.5mA 0.4 1 V

Oscillator

Input level OSCIN pin OSEL = open circuit 1 V

CLL

Input level OSCIN pin OSEL = open circuit 4 V

CLH

Amplitude OSCOUT OSEL = open circuit 4.5 V

OSEL = GND, f = 4.332 MHz

Amplitude OSCIN

(for external drive)

OSEL = GND, f = 8.664 MHz

OSEL = GND, f = 17.328 MHz 150 mVpp

1. The 3rd harmonic (57 kHz) must be less than -40 dB with respect to the input signal plus gain.

0.2 · VS0.3 · V

100 120

mVpp mVpp

6/12

TDA7479 Output timing

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 Figure 3). Whichever clock edge is used by the decoder (rising or falling edge) the data will remain valid for 416.7

Figure 3. RDS timing diagram

s after the clock transition.

RDCL

RDDA

4.3µs td

CLOCK LINE

DATA LINE

4.3µs837.7µs 421µs 421µs

7/12

Oscillator controls (FSEL, OSEL) TDA7479

4 Oscillator controls (FSEL, OSEL)

Three different crystal frequencies can be used. The adoption 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 frequencies

Crystal FSEL (pin configuration)

4.332MHz

8.664MHz

17.328MHz

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. C1 and C2 value

connected to GND or open connected to Vs external resistor of 100K to Vs

Crystal C1 C2

4.332MHz

8.664MHz

17.328MHz

27pF 27pF 27pF

47pF

8/12

TDA7479 Package information

5 Package information

In order to meet environmental requirements, ST (also) offers these devices in ECOPACK® packages. ECOPACK

packages are lead-free. The category of second Level Interconnect is marked on the package and on the inner box label, in compliance with JEDEC Standard JESD97. The maximum ratings related to soldering conditions are also marked on the inner box label.

ECOPACK is an ST trademark. ECOPACK specifications are available at: www.st.com.

Figure 4. SO16 mechanical data and package dimensions

DIM.

A 2.35 2.65 0.093 0.104

A1 0.10 0.30 0.004 0.012

B 0.33 0.51 0.013 0.200

C 0.23 0.32 0.009 0.013

(1)

E 7.40 7.60 0.291 0.299

e 1.27 0 .050

H 10.0 10.65 0.394 0.419

h 0.25 0.75 0.010 0.030

L 0.40 1.27 0.016 0.050

k 0˚ (min.), 8˚ (max.)

ddd 0.10 0.0 04

(1) “D” dimensio n does not include mold flash, prot usions or gate

burrs. Mol d flash, prot usions or gat e burrs shal l not exceed

0.15mm per sid e.

mm inch

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

10.10 10.50 0.398 0.413

OUTLINE AND

MECHANICAL DATA

SO16 (Wide)

0016021 C

9/12

Package information TDA7479

Figure 5. TSSOP16 mechanical data and package dimensions

DIM.

A 1.200 0.047

A1 0.050 0.150 0.002 0.006

A2 0.800 1.000 1.050 0.031 0.039 0.041

b 0.190 0.300 0.007 0.012

c 0.090 0.200 0.005 0.009

D (1) 4.900 5.000 5.100 0.114 0.118 0.122

E 6.200 6.400 6.600 0.244 0 .252 0.260

E1 (1) 4.300 4.400 4.500 0.170 0 .173 0.177

e 0.650 0.026

L 0.450 0.600 0.750 0.018 0.024 0.0 30

L1 1.0 00 0 .039

k 0˚ (min.) 8˚ (max.)

aaa 0.100 0.004

Note: 1. D and E1 does not include mold flash or protrusions.

mm inch

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

Mold flash or potrusions shall not exceed 0.15mm (.006inch) p er side.

OUTLINE AND

MECHANICAL DATA

TSSOP16

(Body 4.4mm)

10/12

0080338 (Jedec MO-153-AB)

TDA7479 Revision history

6 Revision history

Table 8. Document revision history

Date Revision Changes

10-Sep-2004 4 Initial release.

20-Nov-2004 5

02-Dec-2004 6 Modified the order codes table.

04-Nov-2008 7

Add in Table 5: Electrical characteristics on page 5 the “RDS and ARI Detection Sensitivity” parameters.

Document reformatted. Updated Table 1: Device summary on page 1. Updated Section 5: Package information on page 9.

11/12

TDA7479

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12/12

ST TDA7479 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Table 1. Device summary

1 Block diagram and pin description

1.1 Block diagram

Figure 1. Block diagram

1.2 Pin description

Figure 2. Pin connection (top view)

Table 2. Pin description

2 Electrical specification

2.1 Thermal data

Table 3. Thermal data

2.2 Absolute maximum ratings

Table 4. Absolute maximum ratings

2.3 Electrical characteristics

Table 5. Electrical characteristics

3 Output timing

Figure 3. RDS timing diagram

4 Oscillator controls (FSEL, OSEL)

Table 6. Crystal frequencies

Table 7. C1 and C2 value

5 Package information

Figure 4. SO16 mechanical data and package dimensions

Figure 5. TSSOP16 mechanical data and package dimensions

6 Revision history

Table 8. Document revision history