Philips tea5762 DATASHEETS

INTEGRATED CIRCUITS

DATA SH EET

TEA5762

Self tuned radio

Preliminary specification
File under Integrated Circuits, IC01

1995 Jun 23

Philips Semiconductors Preliminary specification

Self tuned radio TEA5762

FEATURES

• The tuning system 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

• The tuning quality is superior and requires no 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, automatic
search and automatic store are possible

• The local (internal) controller function facilitates reduced
and simplified microcontroller software

• The high integration level means fewer external
components with regard to the communication between
the radio and the microcontroller and a simple and small
printed-circuit board (PCB)

• The inherent FUZZY LOGIC behaviour of STR (Self
Tuned Radio), which mimics hand tuning, 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.
The new tuning concept combines the advantages of hand

tuning with electronic facilities and features. User
intelligence is incorporated into the tuning algorithm and
an improvement of the analog signal processing is used for
the AFC function.

ORDERING INFORMATION

TYPE

NUMBER

TEA5762H QFP44 plastic quad flat package; 44 leads (lead length 1.3 mm); body 10 × 10× 1.75 mm SOT307-2

1995 Jun 23 2

NAME DESCRIPTION VERSION

PACKAGE

Philips Semiconductors Preliminary specification

Self tuned radio TEA5762

QUICK REFERENCE DATA

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

V

CC1

V

CC2

V

tune

I

CC1

I

DDD

I

CC2

T

amb

AM performance; note 1
V

10

V

i1

THD total harmonic distortion V
FM performance; note 2
V

10

V

i4

THD total harmonic distortion IF filter

supply voltage 1 2.5 − 12 V
supply voltage 2 for tuning −−12 V
tuning voltage 0.7 − V

CC2

− 0.75 V

supply current 1 AM mode 12 15 18 mA

FM mode 13 16 19 mA

digital supply current AM mode − 3.3 − mA

FM mode − 2.7 − mA

supply current 2 for tuning in preset

−−640 µA

mode (band-end to band-end)
operating ambient temperature −15 − +60 °C

AF output voltage Vi1=5mV 364570 mV
RF sensitivity input voltage S/N = 26 dB 40 55 70 µV

=1mV − 0.8 2.0 %

i1

AF output voltage Vi4=5mV 404857 mV
IF sensitivity input voltage V10= −3 dB;

− 20 30 µV

V10= 0 dB at Vi4=10mV

− 0.3 0.8 %

SFE10.7MS3A20K-A

MPX performance; note 3

α

cs

channel separation Vi4=30mV 26 30 − dB

Notes

1. Conditions AM: V

CC1

=3V; V

CC2

=12V; V

=3V; fi= 1 MHz; m = 0.3; fm= 1 kHz; measured in Fig.8 with S1 in

DDD

position A and S2 in position B; unless otherwise specified.

2. Conditions FM: V

CC1

=3V; V

CC2

= 12 V; V

=3V; fi= 10.7 MHz; ∆fm= 22.5 kHz; fm= 1 kHz; measured in Fig.8

DDD

with S2 in position A and S3 in position A; unless otherwise specified.

3. Conditions MPX: V

CC1

=3V; V

CC2

=12V; V

DDD

=3V; V

i3(L+R)

= 155 mV; V

Fig.8 with S2 in position B and S3 in position B; unless otherwise specified.

= 15.5 mV; fi= 1 kHz; measured in

pilot

1995 Jun 23 3

Philips Semiconductors Preliminary specification

Self tuned radio TEA5762

BLOCK DIAGRAM

(n)

(p)

PILFIL

MO/ST

LFI

VCO

AFLO

AFRO

MUTE

AFC

AFC

AFC

MBE815

BUS-

DATAFM-IF2I

WRITE-

IFGND FSIFMDEM

CLOCK

ENABLE

16

PILOT

12

24

DETECTOR

19 kHz

PLL

9

38 kHz

stereo

DECODER

14

MATRIX

15

mono

stereo

13

MUTE

SDS

TEA5762

21

1817272829333537

FM

DETECTOR

hard mute level

AFC

FM

IF2

AM/FM

INDICATOR

STATUS

REGISTER

IN-LOCK

DETECTOR

up

down

level

PUMP

CHARGE

CIRCUIT

SEQUENTIAL

FM

AM

32

20

19

V/I

CONVERTER

10 11 342

CC2

V

TUNE RFGND2 RFGND1MPXIAFO

AM

DETECTOR

P0
P1AGCAM-IF2I/OAM-MIXERAMOSC

handbook, full pagewidth

Fig.1 Block diagram.

AM

AM

AGC

IF

AM-IF1I

MIXER

FM-IFI1 FM-IFO1

1995 Jun 23 4

FM

IF1

TUNER

SWITCH

39

FM-ON/OFF

SHIFT REGISTER

38

34

7

CC1

V

STAB(A)VSTAB(B)

V

STABILIZER

1

23

DDD

V

RIPPLE

MEMORY

LAST-STATION

5

COUNTI

PROGRAMMABLE

PRESCALER

4

WINDOW

COUNTER

MULTIPLEXER

CGND

CRYSTAL

25

XTAL

DETECTOR

OSCILLATOR

26

DGND

AM

OSCILLATOR

AM

END

FRONT

2

AM-RFI

6404136443130 822

Philips Semiconductors Preliminary specification

Self tuned radio TEA5762

PINNING

SYMBOL PIN DESCRIPTION

RIPPLE 1 ripple capacitor input
AM-RFI 2 AM-RF input
RFGND1 3 RF ground 1 and substrate
CGND 4 counter ground
COUNTI 5 counter input
AMOSC 6 parallel tuned AM oscillator circuit to ground
V

CC1

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)

AFC

(p)

FSI 21 field-strength indicator
V

CC2

V

DDD

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-IF2I 33 FM-IF input 2 (input impedance typical 330 Ω)
V

STAB(B)

FM-IFO1 35 FM-IF output 1 (input impedance typical 330 Ω)
AM-IF2I/O 36 input/output to IFT; output current source
FM-IFI1 37 FM-IF input 1 (input impedance typical 330 Ω)
V

STAB(A)

FM-ON/OFF 39 FM ON/OFF port
AM-MIXER 40 open-collector output to IFT

7 supply voltage 1

19 AFC negative output
20 AFC positive output

22 supply voltage 2 (for tuning)
23 digital supply voltage

34 internal stabilized supply voltage (B)

38 internal stabilized supply voltage (A)

1995 Jun 23 5

Philips Semiconductors Preliminary specification

Self tuned radio TEA5762

SYMBOL PIN DESCRIPTION

AM-IF1I 41 IFT or ceramic filter input (input impedance typical 3 kΩ)
RFGND2 42 FM-RF ground 2
n.c. 43 not connected
AGC 44 AGC capacitor input

handbook, full pagewidth

RIPPLE

AM-RFI

RFGND1

CGND

COUNTI

AMOSC

V

CC1

TUNE

VCO

AFO

MPXI

AGC

n.c.

RFGND2

AM-IF1I

AM-MIXER

44

43

42

41

40

1
2
3
4
5

15

AFRO

TEA5762

16

PILFIL

6
7
8

9
10
11

12

13

14

LFI

MUTE

AFLO

STAB(A)

FM-ON/OFF

V

39

38

17

18

IFGND

FMDEM

FM-IFI1
37

19

(n)

AFC

AM-IF2I/O
36

20

(p)

AFC

STAB(B)

FM-IFO1

V

35

34

21

22

FSI

CC2

V

33

FM-IF2I

32

AFC

31

P1

30

P0

29

WRITE-ENABLE

28

DATA
BUS-CLOCK

27
26

DGND

25

XTAL

24

MO/ST

23

V

DDD

MBE820

1995 Jun 23 6

Fig.2 Pin configuration.

Philips Semiconductors Preliminary specification

Self tuned radio 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) or an IFT
combined with a ceramic filter; the second 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

The tuning-concept of STR is based on 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. Thus only a
few external components are required.

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
In preset mode, the microcontroller has to load information

such as frequency band, frequency and mono/stereo. This
information has to be sent via the bus to STR. The internal
algorithm controls the tuning sequence as follows: the
information is loaded into a shift register, a last-station
memory and the counter. The Automatic Frequency
Control (AFC) is switched off. The counter starts counting
the VCO frequency and the tuning voltage is varied until
the desired frequency roughly equals the real frequency.
The AFC is then switched on and the counter is switched
off. The real frequency is now tuned precisely 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
obtain 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 or pulling, the in-lock signal becomes
logic 0, the synthesizer will be switched on again and the
algorithm will be repeated.

EARCH OPERATION

S
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 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
the found station will be counted by the counter and 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
microcontroller decides whether the frequency is within the
desired frequency band. If it is, this frequency can be
stored under a preset and if it is not, a new search action
should be started.

1995 Jun 23 7

Philips Semiconductors Preliminary specification

Self tuned radio TEA5762

Description of the bus

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

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.

The TEA5762 has a 25-bit shift register; see Table 3 for an
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 1.

The bus protocol is depicted in Figs 3 and 4.

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 programmable bits which e.g. can be used as

P1.18 port note 1 user programmable bits which e.g. can be used as

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

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

15 dummy − buffer
F.14 to F.0 (LSB) frequency − determine the tuning frequency of the radio;

Table 1 Bus signals

SIGNAL PIN DESCRIPTION

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

Table 2 Bus clock functions

BUS CLOCK PIN 24 RESULT

LOW LOW stereo

LOW HIGH mono
HIGH LOW tuned
HIGH HIGH not tuned

band switch driver

band switch driver

automatic search, automatic store or manual search

automatic search, automatic store or manual search

see Table 6 for the bit values

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.

1995 Jun 23 8

Philips Semiconductors Preliminary specification

Self tuned radio TEA5762

Table 4 Truth table for bits 21 and 20

B0 B1 BAND SELECT

00FM

(1)

01MW
10LW
11SW

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

SIGNAL RECEPTION

(1)

S1 S0

FM IF INPUT AM RF INPUT

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

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

BIT BIT VALUEFMVALUE

(kHz)

14 2
13 2
12 2
11 2
10 2

92
82
72
62
52
42
32
22
12
02

14
13
12
11
10

9
8
7
6
5
4
3
2
1
0

− 16384

102400 8192

51200 4096
25600 2048
12800 1024

6400 512
3200 256
1600 128

800 64
400 32
200 16
100 8

50 4
25 2

12.5 1

Notes

1. FM value of the affected oscillators;
FM VALUE = FM-RF + FM-IF.

2. AM value of the affected oscillators;
AM VALUE = AM-RF + AM-IF.

(1)

AM

VALUE

(kHz)

(2)

1995 Jun 23 9

Philips Semiconductors Preliminary specification

Self tuned radio 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.

handbook, full pagewidth

WRITE-ENABLE

BUS-CLOCK

DATA

data shiftdata available after search ready

MSB is LOW

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 accepts
one bit into LSB. At clock LOW the microcontroller writes
data; see Fig.4.

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

data read

data available

MBE817

handbook, full pagewidth

WRITE-ENABLE

BUS-CLOCK

DATA

Fig.3 Read data.

MBE818

data changedata shift

Fig.4 Write data.

1995 Jun 23 10