Philips tea5757, tea5759 DATASHEETS

INTEGRATED CIRCUITS

DATA SH EET

TEA5757; TEA5759

Self Tuned Radio (STR)

Product specification
Supersedes data of 1996 Jan 09
File under Integrated Circuits, IC01

1999 Aug 26

Philips Semiconductors Product specification

Self Tuned Radio (STR) TEA5757; TEA5759

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 (radio and tuning synthesizer
on one chip) means fewer external components with
regard to the communication between the radio and the
microcontroller (90% less components compared to the
digital tuning application of a radio IC with external PLL
tuning function) and a simple and small printed-circuit
board

• Therewill be no applicationconsiderationsfor the tuning
system, with regards to quality and high integration
level, since there will be no external 110 MHz buffers,
loop filter or false lock elimination

• The inherent FUZZY LOGIC behaviour of the Self
Tuned Radio (STR), whichmimics 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

• 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)

• High input sensitivity

• Low output distortion

• Due to the new tuning concept, the tuning is

independent of the channel spacing.

GENERAL DESCRIPTION

The TEA5757; TEA5759 is a 44-pin integrated AM/FM
stereo radio circuit including a novel tuning concept.
The radio part is based on the TEA5712.

The TEA5757 is used in FM-standards in which the local
oscillator frequency is above the radio frequency
(e.g. European and American standards).

The TEA5759 is the version in which the oscillator
frequency is below the radio frequency
(e.g. Japanese standard).

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

TEA5757H QFP44 plastic quad flat package;44 leads (lead length 1.3 mm); body
TEA5759H

1999 Aug 26 2

NAME DESCRIPTION VERSION

10 × 10 × 1.75 mm

PACKAGE

SOT307-2

Philips Semiconductors Product specification

Self Tuned Radio (STR) TEA5757; TEA5759

QUICK REFERENCE DATA

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

V

CC1

V

CC2

V

tune

I

CC1

I

DD

I

CC2

T

amb

AM performance; note 1
V

10

V

i1

THD total harmonic distortion V
FM performance; note 2
V

10

V

i5

THD total harmonic distortion IF filter

MPX performance; note 3

α

cs

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

− 0.75 V

CC2

supply current AM mode 12 15 18 mA

FM mode 13 16 19 mA

supply current AM mode − 3.3 − mA

FM mode − 2.7 − mA

supply current for tuning in preset

−−800 µA

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

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

=1mV − 0.8 2.0 %

i1

AF output voltage Vi5=1mV 404857 mV
RF limiting sensitivity V10at −3 dB;

0.4 1.2 3.8 µV

V10is 0 dB at Vi5=1mV

− 0.3 0.8 %

SFE10.7MS3A20K-A

channel separation 26 30 − dB

Notes

1. V

2. V

3. V

=3V;V

CC1

in position B; Vn refers to pin voltages; V

=3V; V

CC1

CC2

CC2

=12V;V

= 12 V; V

=3V;fi= 1 MHz; m = 0.3; fm= 1 kHz; measured in Fig.9 with S1 in position A andS2

DDD

refers to test circuit (see Fig.9).

i(n)

=3V; fi= 100 MHz; ∆fm= 22.5 kHz; fm= 1 kHz; measured in Fig.9 with S2, S3

DDD

and S5 in position A; Vn refers to pin voltages; V

CC1

=3V; V

CC2

= 12 V; V

DDD

=3V; V

i3(L + R)

refers to test circuit (see Fig.9).

i(n)

= 155 mV; V

and S3 in position B.

1999 Aug 26 3

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

pilot

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1999 Aug 26 4

BLOCK DIAGRAM

Philips Semiconductors Product specification

Self Tuned Radio (STR) TEA5757; TEA5759

FM-RFI

RFGND

DATA

BUS-CLOCK

WRITE-ENABLE

V

STAB(A)

V

STAB(B)

V

CC1

V

DDD

RIPPLE

XTAL

DGND

AM-RFI

FM-RFO

43

FM

42

FRONT-END

28
27
29

38
34
7

STABILIZER

23
1

PRESCALER

MULTIPLEXER

25

CRYSTAL

26

OSCILLATOR

31

P1

30

P0

AM

2

FRONT-END

FMOSC

FM

OSCILLATOR

SHIFT REGISTER

LAST-STATION

PROGRAMMABLE

AM

OSCILLATOR

MEMORY

COUNTER

WINDOW

DETECTOR

FM-IFI1 FM-IFI2

FM-MIXER

FM

MIXER

FM

AM

AM

MIXER

FM-IFO1

FM
IF1

STATUS

REGISTER

SEQUENTIAL

CIRCUIT

AM

IF

down
level

AGC

IFGND FSIFMDEM

21

181739 37 333535

16

PILFIL

24

MO/ST

12

LFI

9

VCO

14

AFLO
AFRO

15

13

MUTE

19

AFC
AFC
AFC

(n)
(p)

20
32

AM

FM

DETECTOR

TEA5757;

TEA5759

FM
IF2

AM/FM

INDICATOR

up

IN-LOCK

DETECTOR

CHARGE

PUMP

hard mute

AFC

DETECTOR

19 kHz

38 kHz

stereo

level

CONVERTER

PILOT

DETECTOR

PLL

DECODER

stereo

MATRIX

mono

SDS

MUTE

V/I

6

40 41

AM-MIXERAMOSC

36 44

AM-IFI/O2

AM-IFI1

Fig.1 Block diagram.

AGC

handbook, full pagewidth

TUNE

822

AFO

V

CC2

10

MPXI

11

4

RFGND

MHA111

Philips Semiconductors Product specification

Self Tuned Radio (STR) TEA5757; TEA5759

PINNING

SYMBOL PIN DESCRIPTION

RIPPLE 1 ripple capacitor input
AM-RFI 2 AMRF input
FM-RFO 3 parallel tuned FMRF circuit to ground
RFGND 4 RF ground and substrate
FMOSC 5 parallel tuned FM-oscillator circuit to ground
AMOSC 6 parallel tuned AM-oscillator circuit to ground
V

CC1

TUNE 8 tuning current output
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-circuit
FM-IFI2 33 FMIF input 2 (input impedance typical 330 Ω)
V

STAB(B)

FM-IFO1 35 FMIF output 1 (output impedance typical 330 Ω)
AM-IFI/O2 36 input/output to IF-Tank (IFT); output: current source
FM-IFI1 37 FMIF input 1 (input impedance typical 330 Ω)
V

STAB(A)

FM-MIXER 39 ceramic filter output (output impedance typical 330 Ω)
AM-MIXER 40 open-collector output to IFT

7 supply voltage

19 AFC negative output
20 AFC positive output

22 supply voltage for tuning
23 digital supply voltage

34 internal stabilized supply voltage (B)

38 internal stabilized supply voltage (A)

1999 Aug 26 5

Philips Semiconductors Product specification

Self Tuned Radio (STR) TEA5757; TEA5759

SYMBOL PIN DESCRIPTION

AM-IFI1 41 IFT or ceramic filter input (input impedance typical 3 kΩ)
RFGND 42 FMRF ground
FM-RFI 43 FMRF aerial input (input impedance typical 40 Ω)
AGC 44 AGC capacitor input

handbook, full pagewidth

RIPPLE

AM-RFI

FM-RFO

RFGND
FMOSC

AMOSC

V

CC1

TUNE

VCO

AFO

MPXI

AGC

FM-RFI

RFGND

AM-IFI1

AM-MIXER

44

43

42

41

40

1
2
3
4
5

14

AFLO

TEA5757H
TEA5759H

15

16

AFRO

PILFIL

6
7
8

9
10
11

12

13

LFI

MUTE

STAB(A)

FM-MIXER

V

39

38

17

18

IFGND

FMDEM

FM-IFI1
37

19

(n)

AFC

AM-IFI/O2
36

20

(p)

AFC

STAB(B)

FM-IFO1

V

35

34

21

22

FSI

CC2

V

33

FM-IFI2

32

AFC

31

P1

30

P0

29

WRITE-ENABLE

28

DATA
BUS-CLOCK

27
26

DGND

25

XTAL

24

MO/ST

23

V

DDD

MHA112

Fig.2 Pin configuration.

1999 Aug 26 6

Philips Semiconductors Product specification

Self Tuned Radio (STR) TEA5757; TEA5759

FUNCTIONAL DESCRIPTION

The TEA5757; TEA5759 is an integrated AM/FM stereo
radio circuit including 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
an IFT combined with a ceramic filter; the second one is
an IFT.

The FM circuit incorporates a tuned RF stage, a double
balanced mixer, a one-pin oscillator and is designed for
distributed IF ceramic filters. The FM quadrature detector
uses a ceramic resonator (or LC).

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

Tuning

The tuning concept of the Self Tuned Radio (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; 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 the shift register, the
last-station memory and the counter.

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

3. The counter starts counting the frequency and the
tuning voltage is varied until the desired frequency
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 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 microcontroller decides whether the frequency is
withinthedesired frequency band. Ifso,thisfrequency can
be stored under a preset and if not, a new search action
should be started.

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.

1999 Aug 26 7

Philips Semiconductors Product specification

Self Tuned Radio (STR) TEA5757; TEA5759

Description of the bus

The TEA5757; TEA5759radio has abus whichconsists 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 3 Explanation of the shift register bits

BIT DESCRIPTION

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

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

M.22 mono/stereo 0 stereo is allowed

B0.21 band see Table 4 selects FM/MW/LW/SW band
B1.20
P0.19 port note 1 user programmable bits which e.g. can be used as band
P1.18
S0.17 search-level of station see Table 5 determines the locking field strength during an
S1.16
15 dummy − buffer
F.14 to F.0 (LSB) frequency − determine the tuning frequency of the radio; see Table 6

LOGIC

STATE

1 during the search action

1 indicates if the radio has to search up

1 mono is required (radio switched to forced mono)

Table 2 Bus-clock functions

BUS-CLOCK MO/ST (PIN 24) RESULT

LOW LOW stereo
LOW HIGH mono
HIGH LOW tuned
HIGH HIGH not tuned

The TEA5757; TEA5759 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 0.

The bus protocol is depicted in Figs 3 and 4.

RESULT

switch driver

automatic search, automatic store or manual search

for the bit values

Note

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

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

1999 Aug 26 8

Philips Semiconductors Product specification

Self Tuned Radio (STR) TEA5757; TEA5759

Table 4 Truth table for bits B0.21 and B1.20

B0.21 B1.20 BAND SELECT

00FM
01MW
10LW
11SW

Table 5 Truth table for bits S1.16 and S0.17

SIGNAL RECEPTION

S1.16 S0.17

FM

(µV)

0 0 >5 >28
0 1 >10 >40
1 0 >30 >63
1 1 >150 >1000

AM

(µV)

Table 6 Values for bits F.14 to F.0

BIT BIT VALUEFMVALUE

(1)

(kHz)

F.14 2
F.13 2
F.12 2
F.11 2
F.10 2

F.9 2
F.8 2
F.7 2
F.6 2
F.5 2
F.4 2
F.3 2
F.2 2
F.1 2
F.0 2

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:
a) FM VALUE = FMRF + FMIF (for TEA5757).
b) FM VALUE = FMRF − FMIF (for TEA5759).

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

AM

VALUE

(kHz)

(2)

1999 Aug 26 9

Philips Semiconductors Product specification

Self Tuned Radio (STR) TEA5757; TEA5759

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 TEA5757; TEA5759 (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.

1999 Aug 26 10