Philips TEA5762 Datasheet

DATA SH EET

Product specification
Supersedes data of 1995 Jun 23
File under Integrated Circuits, IC01

1999 Aug 04

INTEGRATED CIRCUITS

TEA5762

Self Tuned Radio (STR)

1999 Aug 04 2

Philips Semiconductors Product specification

Self Tuned Radio (STR) TEA5762

FEATURES

• The tuningsystem has an optimized IC partitioning both
from application (omitting interferences) and flexibility
(removable front panel option) point of view: the tuning
synthesizer is on-chip with the radio

• Thetuning quality issuperior and requiresno IF-counter
for stop-detection; it is insensitive to ceramic filter
tolerances

• In combination with the microcontroller, fast, low-power
operation of preset mode, manual-search, auto-search
and auto-store are possible

• Thelocal (internal) controller functionfacilitatesreduced
and simplified microcontroller software

• The high integration level means fewer external
components with regard to the communication between
the radio andthe microcontroller anda simpleand small
Printed-Circuit Board (PCB)

• The inherent FUZZY LOGIC behaviour of the Self
Tuned Radio (STR), which mimics hand tuning and
yields a potentially fast yet reliable tuning operation

• The level of the incoming signal at which the radio must
lock is software programmable

• Two programmable ports

• FM-on/off port to control the external FM front-end

• High selectivity with distributed IF gain

• Soft mute

• Signal dependent stereo-blend

• High impedance MOSFET input on AM

• Wide supply voltage range of 2.5 to 12 V

• Low current consumption 18 mA at AM and FM

(including tuning synthesizer for AM)

• Low noise figure

• Low output distortion

• Due to the new tuning concept, the tuning is

independent of the channel spacing.

GENERAL DESCRIPTION

The TEA5762 is a 44-pin integrated AM-radio and FM-IF
and demodulator part including a novel tuning concept.
The radio part is based on the TEA5712.

It is designed for the use with an external FM front-end.
Thenew tuning conceptcombinesthe advantages ofhand

tuning with electronic facilities and features. User
‘intelligence’ is incorporated into the tuning algorithm and
animprovementofthe analog signal processing isusedfor
the AFC function.

ORDERING INFORMATION

TYPE

NUMBER

PACKAGE

NAME DESCRIPTION VERSION

TEA5762H QFP44 plastic quad flat package; 44 leads (lead length 1.3 mm);

body 10 × 10 × 1.75 mm

SOT307-2

1999 Aug 04 3

Philips Semiconductors Product specification

Self Tuned Radio (STR) TEA5762

QUICK REFERENCE DATA

Notes

1. V

CC1

=3V;V

CC2

=12V;V

DDD

=3V;fi= 1 MHz; m = 0.3; f

mod

= 1 kHz; measured in Fig.9 with S1 in position A; S2

in position B; unless otherwise specified.

2. V

CC1

=3V; V

CC2

= 12 V; V

DDD

=3V; fi= 10.7 MHz; ∆fm= 22.5 kHz; fm= 1 kHz; measured in Fig.9 with S2 in

position A; S3 in position A; unless otherwise specified.

3. V

CC1

=3V; V

CC2

= 12 V; V

DDD

=3V; V

i3(L + R)

= 155 mV; V

pilot

= 15.5 mV; fi= 1 kHz; measured in Fig.9 with S2 in

position B; S3 in position B; unless otherwise specified.

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

V

CC1

supply voltage 2.5 − 12 V

V

CC2

supply voltage for tuning −−12 V

V

tune

tuning voltage 0.7 − V

CC2

− 0.75 V

I

CC1

supply current AM mode 12 15 18 mA

FM mode 13 16 19 mA

I

DD

supply current AM mode − 3.3 − mA

FM mode − 2.7 − mA

I

CC2

supply current for tuning in preset
mode (band-end to band-end)

−−800 µA

T

amb

ambient temperature −15 − +60 °C
AM performance; note 1
V

10

AF output voltage Vi1= 5 mV 36 45 70 mV
V

i1

RF sensitivity input voltage S/N = 26 dB 40 55 70 µV
THD total harmonic distortion V

i1

=1mV − 0.8 2.0 %
FM performance; note 2
V

10

AF output voltage Vi4= 5 mV 40 48 57 mV

V

i4

IF sensitivity input voltage V10= −3 dB; V10=0dB

at Vi4=10mV

− 20 30 µV

THD total harmonic distortion IF filter

SFE10.7MS3A20K-A

− 0.3 0.8 %

MPX performance; note 3

α

cs

channel separation Vi4=30mV 26 30 − dB

1999 Aug 04 4

Philips Semiconductors Product specification

Self Tuned Radio (STR) TEA5762

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BLOCK DIAGRAM

handbook, full pagewidth

PRESCALER

PROGRAMMABLE

COUNTER

STABILIZER

WINDOW

DETECTOR

LAST-STATION

MEMORY

AM/FM

INDICATOR

IN-LOCK

DETECTOR

FM

DETECTOR

PILOT

DETECTOR

CHARGE

PUMP

MULTIPLEXER

CRYSTAL

OSCILLATOR

SHIFT REGISTER

TUNER

SWITCH

FM
IF1

FM
IF2

SEQUENTIAL

CIRCUIT

STATUS

REGISTER

AM

FRONT

END

AM

OSCILLATOR

AM

DETECTOR

V/I

CONVERTER

AM

MIXERAMIF

AGC

AFC

hard mute

level

PLL

DECODER

MATRIX

SDS

MUTE

up
down
level

FM-ON/OFF

V

STAB(A)

V

STAB(B)

AM-RFI

XTAL

COUNTI

RIPPLE

25

4

5

23

1

26

2

P1AGCAM-IFI/O2AM-MIXERAMOSC

AM-IFI1

P0

6404136443130 822

32

20

19

13

15

14

9

12

24

16

1817272829333537

39

38
34

7

21

10 11 342

MO/ST

AFRO

MUTE

AFC

(n)

AFC

(p)

AFC

VCO

LFI

PILFIL

AFLO

stereo

stereo

mono

38 kHz

19 kHz

WRITE-

ENABLE

DATAFM-IFI2

FM-IFI1 FM-IFO1

BUS-

CLOCK

V

CC1

V

DDD

TEA5762

FM
AM

CGND

DGND

TUNE RFGND RFGNDMPXIAFO

V

CC2

IFGND FSIFMDEM

MBE815

Fig.1 Block diagram.

1999 Aug 04 5

Philips Semiconductors Product specification

Self Tuned Radio (STR) TEA5762

PINNING

SYMBOL PIN DESCRIPTION

RIPPLE 1 ripple capacitor input
AM-RFI 2 AMRF input
RFGND 3 RF ground and substrate
CGND 4 counter ground
COUNTI 5 counter input
AMOSC 6 parallel tuned AM-oscillator circuit to ground
V

CC1

7 supply voltage
TUNE 8 tuning output current
VCO 9 voltage controlled oscillator input
AFO 10 AM/FM AF output (output impedance typical 5 kΩ)
MPXI 11 stereo decoder input (input impedance typical 150 kΩ)
LFI 12 loop filter input
MUTE 13 mute input
AFLO 14 left channel output (output impedance typical 4.3 kΩ)
AFRO 15 right channel output (output impedance typical 4.3 kΩ)
PILFIL 16 pilot detector filter input
IFGND 17 ground of IF, detector and MPX stage
FMDEM 18 ceramic discriminator input
AFC

(n)

19 AFC negative output

AFC

(p)

20 AFC positive output
FSI 21 field strength indicator
V

CC2

22 supply voltage for tuning
V

DDD

23 digital supply voltage
MO/ST 24 mono/stereo and tuning indication output
XTAL 25 crystal input
DGND 26 digital ground
BUS-CLOCK 27 bus-clock input
DATA 28 bus data input/output
WRITE-ENABLE 29 bus write-enable input
P0 30 programmable output port (P0)
P1 31 programmable output port (P1)
AFC 32 450 kHz LC-input circuit for AM AFC
FM-IFI2 33 FMIF input 2 (input impedance typical 330 Ω)
V

STAB(B)

34 internal stabilized supply voltage (B)
FM-IFO1 35 FMIF output 1 (input impedance typical 330 Ω)
AM-IFI/O2 36 input/output to IFT; output: current source
FM-IFI1 37 FMIF input 1 (input impedance typical 330 Ω)
V

STAB(A)

38 internal stabilized supply voltage (A)
FM-ON/OFF 39 FM ON/OFF port
AM-MIXER 40 open-collector output to IFT

1999 Aug 04 6

Philips Semiconductors Product specification

Self Tuned Radio (STR) TEA5762

AM-IFI1 41 IFT or ceramic filter input (input impedance typical 3 kΩ)
RFGND 42 FMRF ground
n.c. 43 not connected
AGC 44 AGC capacitor input

SYMBOL PIN DESCRIPTION

Fig.2 Pin configuration.

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TEA5762H

MBE820

1

2

3

4

5

6

7

8

9

10
11

33
32
31
30
29
28
27
26
25
24
23

12

13

14

15

16

17

18

19

20

21

22

44

43

42

41

40

39

38

37

36

35

34

RIPPLE

AM-RFI

RFGND

CGND

COUNTI

AMOSC

V

CC1

TUNE

VCO

AFO

MPXI

FM-IFI2
AFC
P1
P0
WRITE-ENABLE
DATA

BUS-CLOCK

DGND
XTAL
MO/ST
V

DDD

LFI

MUTE

AFLO

AFRO

PILFIL

IFGND

FMDEM

AFC

(n)

AFC

(p)

FSI

V

CC2

AGC

n.c.

RFGND

AM-IFI1

AM-MIXER

FM-ON/OFF

V

STAB(A)

FM-IFI1

AM-IFI/O2

FM-IFO1

V

STAB(B)

1999 Aug 04 7

Philips Semiconductors Product specification

Self Tuned Radio (STR) TEA5762

FUNCTIONAL DESCRIPTION

The TEA5762 is an integrated radio circuit with
AM-receiver and FM-IF part with demodulator and stereo
decoder. The circuit includes digital tuning and control
functions.

The radio

The AM circuit incorporates a double balanced mixer, a
one-pin low-voltage oscillator (up to 30 MHz) and is
designed for distributed selectivity.

The AM input is designed to be connected to the top of a
tuned circuit. AGC controls the IF amplification and for
large signals it lowers the input impedance of the AM
front-end.

The first AM selectivity can be an IF-Tank (IFT) as well as
anIFT combined withaceramic filter; thesecond one is an
IFT.

For FM operation an external FM front-end is necessary.
This is switched on and off by the FM-ON/OFF signal
which is generated in the bus system.

The AFC circuit in the TEA5762 provides a tuning voltage
to drive the VCO of the external FM front-end.

The frequency of the external VCO is counted in the Self
Tuned Radio (STR) tuning system.

The FM-IF circuit is designed for distributed IF ceramic
filters. The FM quadratic detector uses a ceramic
resonator.

The PLL stereo decoder incorporates a signal dependent
stereo-blend circuit and a soft-mute circuit.

Tuning

Thetuning-concept of Self TunedRadio(STR) is basedon
FUZZY LOGIC: it mimics hand tuning (hand tuning is a
combination of coarse and fine tuning to the qualitatively
best frequency position). As a consequence the tuning
system is very fast.

The tuning algorithm, which is controlled by the sequential
circuit (see Fig.1), is completely integrated; so there are
only a few external components needed.

The bus and the microcontroller can be kept very simple.
The bus only consists of three wires (BUS-CLOCK, DATA
and WRITE-ENABLE). The microcontroller must basically
give two instructions:

• Preset operation

• Search operation.

PRESET OPERATION
Inpreset mode, themicrocontroller has toload information

suchas frequency band,frequency and mono/stereo.This
information has to be sent via the bus to the STR.
The internal algorithm controls the tuning sequence as
follows:

1. The information is loaded into a shift register, a
last-station memory and the counter.

2. The Automatic Frequency Control (AFC) is switched
off.

3. The counter starts counting the VCO frequency and
the tuning voltage is varied until the desiredfrequency
roughly equals the real frequency.

4. The AFC is then switched on and the counter is
switched off.

5. The real frequency is more precisely tuned to the
desired frequency.

After the AFC has tuned the real frequency to the desired
frequency an in-lock signal can be generated. In order to
get a reliable in-lock signal, there are two parameters
measured: the field strength and the S-curve. The field
strength indicates the strength of the station and by
looking at the S-curve the system can distinguish false
in-locks from real in-locks (false in-locks occur on the
wrong slope of the S-curve).

In the FM mode the tuning voltage controls the VCO of the
external FM front-end and the frequency of the VCO is
counted in the TEA5762.

In the event of fading orpulling thein-lock signal becomes
logic 0 and the synthesizer will be switched-on again and
the algorithm will be repeated.

SEARCH OPERATION
During a search operation, the only action the

microcontroller has to take is: sending the desired band
plus the direction and the search sensitivity level to the
STR. The search operation is performed by the charge
pump until an in-lock signal is generated (combination of
measuring the field strength and the S-curve). The AFC
then fine tunes to the station. The frequency belonging to
thefound station willbecounted by the counterand written
into the last-station memory and the shift register of the
counter. At this time the frequency is available in the shift
register and can be read by the microcontroller. The
microcontrollerdecideswhetherthe frequency is within the
desiredfrequency band. If so,thisfrequency can bestored
under a preset and if not, a new search action should be
started.

1999 Aug 04 8

Philips Semiconductors Product specification

Self Tuned Radio (STR) TEA5762

To ensure that the search function operates correctly
under all conditions the following search sequence must
be applied:

• Store the current frequency in the memory

• Issue the search command

• Wait for data valid and read the new frequency

• If the new frequency is the same as the stored

frequency, issue a pre-set step (e.g. 50 kHz) and start
the search sequence again.

Description of the bus

The TEA5762 radio has a bus which consists of three
wires, as shown in Table 1.

Table 1 Bus signals

SIGNAL DESCRIPTION PIN

BUS-CLOCK software driven clock input 27
DATA data input/output 28
WRITE-ENABLE write/read-input 29

These three signals, together with the mono/stereo pin
(MO/ST; pin 24), communicate with the microcontroller.
The mono/stereo indicator has two functions, which are
controlled by the BUS-CLOCK, as shown in Table 2.

Table 2 Bus-clock functions

TheTEA5762 has a 25-bitshiftregister; see Table 3 foran
explanation of the shift register bits.

If in search mode no transmitter can be found, all
frequency bits of the shift register are set to logic 0.

The bus protocol is depicted in Figs 3 and 4.

BUS-CLOCK MO/ST (PIN 24) RESULT

LOW LOW stereo

LOW HIGH mono
HIGH LOW tuned
HIGH HIGH not tuned

Table 3 Explanation of the shift register bits

BIT DESCRIPTION

LOGIC
STATE

RESULT

S.24 (MSB) search start/end 0 after a search when a station is found or after a preset

1 during the search action

D.23 search up/down 0 indicates if the radio has to search down

1 indicates if the radio has to search up

M.22 mono/stereo 0 stereo is allowed

1 mono is required (radio switched to forced mono)
B0.21 band see Table 4 selects FM/MW/LW/SW band
B1.20 band see Table 4 selects FM/MW/LW/SW band
P0.19 port note 1 user programmablebits which e.g.can be used as band

switch driver

P1.18 port note 1 user programmablebits which e.g.can be used as band

switch driver

S0.17 search-level of station see Table 5 determines the locking field strength during an

automatic search, automatic store or manual search

S1.16 search-level of station see Table 5 determines the locking field strength during an

automatic search, automatic store or manual search
15 dummy − buffer
F.14 to F.0 (LSB) frequency − determine the tuning frequency of the radio;see Table 6

for the bit values

1999 Aug 04 9

Philips Semiconductors Product specification

Self Tuned Radio (STR) TEA5762

Note

1. The output pins 30 and 31 can drive currents up to
5 mA; bits 19 (P0) and 18 (P1) control the output
voltage of the control pins P0 (pin 30) and P1 (pin 31):

a) Bit 19 (P0) LOW sets P0 (pin 30) to LOW.
b) Bit 19 (P0) HIGH sets P0 (pin 30) to HIGH.
c) Bit 18 (P1) LOW sets P1 (pin 31) to LOW.
d) Bit 18 (P1) HIGH sets P1 (pin 31) to HIGH.

Table 4 Truth table for bits 21 and 20

Note

1. When FM is selected, the control output FM-ON/OFF
is set LOW to switch on the external FM front-end.

Table 5 Truth table for bits 16 and 17

Note

1. The given values for signal reception are
corresponding to a −3 dB point of 20 µV for FM.

Table 6 Values for bits 14 to 0

Notes

1. FM value of the affected oscillators:
FM VALUE = FMRF + FMIF.

2. AM value of the affected oscillators:
AM VALUE = AMRF + AMIF.

B0 B1 BAND SELECT

00FM

(1)

01MW
10LW
11SW

S1 S0

SIGNAL RECEPTION

(1)

FM IF INPUT

(µV)

AM RF INPUT

(µV)

0 0 >50 >28
0 1 >100 >40
1 0 >300 >63
1 1 >1500 >1000

BIT BIT VALUEFMVALUE

(1)

(kHz)

AM

VALUE

(2)

(kHz)

14 2

14

− 16384

13 2

13

102400 8192

12 2

12

51200 4096

11 2

11

25600 2048

10 2

10

12800 1024

92

9

6400 512

82

8

3200 256

72

7

1600 128

62

6

800 64

52

5

400 32

42

4

200 16

32

3

100 8

22

2

50 4

12

1

25 2

02

0

12.5 1

1999 Aug 04 10

Philips Semiconductors Product specification

Self Tuned Radio (STR) TEA5762

READING DATA
While WRITE-ENABLE is LOW data can be read by the

microcontroller. At a rising edge of the BUS-CLOCK, data
is shifted out of the register. This data is available from the
point where the BUS-CLOCK is HIGH until the next rising
edge of the BUS-CLOCK occurs (see Fig.3).

To read the entire shift register 24 clock pulses are
necessary.

WRITING DATA
While WRITE-ENABLE is HIGH the microcontroller can

transmit data to the TEA5762 (hard mute is active). At a
rising edge of the BUS-CLOCK, the register shifts and
acceptsone bit intoLSB. At clock LOW the microcontroller
writes data (see Fig.4).

To write the entire shift register 25 clock pulses are
necessary.

Fig.3 Read data.

handbook, full pagewidth

WRITE-ENABLE

BUS-CLOCK

DATA

data read

data available

data shiftdata available after search ready

MSB is LOW

MBE817

Fig.4 Write data.

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data changedata shift

MBE818

WRITE-ENABLE

BUS-CLOCK

DATA