SGS Thomson Microelectronics TDA7335 Datasheet



STEREO PREAMP + AMS + DOLBY B*

NOISE REDUCTIONPROCESSOR

DUAL CHANNEL PROCESSOR FOR PLAY­BACK APPLICATIONS.

STEREODOLBYB NR SYSTEM
LOW NOISE HEAD PREAMPLIFIER
MUTE, AUTOREVERSE, AMS (AUDIO MU-

SIC SENSOR)FUNCTIONS
INTERNALSWITCHES FOR EQUALIZATION
DOLBY REFERENCE LEVEL -6dBm

(388.2mV
MINIMUM NUMBER OF EXTERNALCOMPO-

NENTS
LOW SUPPLY CURRENT(18mA)
MIXED BIPOLAR/CMOSTECHNOLOGY

DESCRIPTION

The TDA7335 is a monolithic BICmos IC de­signed for use in stereo cassette player systems.

The device includes two separate audio channels
composed by low noise preamplifier, Dolby B
noise reduction system and Audio Music Sensor.

The dual preamplifier contains mute, autoreverse,
metal/normalfacilities for amplificationof low level
signal in applications requiring very low noise per­formances.

Each channel consists of two cascaded opera­tional amplifiers.

The first one, AMP1, has a fixed gain of 36dB,
low noise forward/reverse switchable input, and
allows magnetic heads connection directly to
ground. The secondone, AMP2, is a standard op­erational amplifier whose equalizing external
componentsfix the frequencyresponse.

The Audio Music Sensor circuit detects the inter­program space and then the starting point of mu­sical programs (the interprogram time and pro­gram detectiontime are externallyselectable).

The device contains Dolby B decoder NR chains
requiring very few external components and do
not require coils.

RMS)

ORDERING NUMBER: TDA7335

PIN CONNECTION

TDA7335

SDIP30

(Top view)

* Dolby B and the Double-D symbol are

trademarks of Dolby Laboratories Li­censing Corporation, San Francisco,
California94103-4813,USA.
This device is available only to Licens­ing and application information may be
obtainedfrom Dolby Lab.

November 1999

1/20

TDA7335

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

V

S

tot Total Power Dissipation 1 W

P
T

op

T

stg

THERMAL DATA

Rth j-pins Thermal resistance junction-pins 85 °C/W

PIN FUNCTIONS

N. Name VDC (V) Function

1 GND Ground

2,3 IN L

4,27 EQLI, EQRI 4.6 Equalizer Inputs
5, 26 EQLO, EQRO 4.6 Equalizer Outputs
6, 25 OUTL, OUTR 4.6 Preamplifier Outputs
7, 24 DINL, DINR V

8 AMS SW 5.6 Audio Music Sensor Switch (ON/OFF) HIGH = ON

9 INTP Interprogram Time Constant (”Signal Detection”)
10 INTS Interspace Time Constant (”Blank Detection”)
11 MUTE Mute Switch ON = LOW (2)

12, 19 TLC, TCR 0.4 Dolby Time Constants
13, 18 DOUTL, DOUTR V

14 I
15 F/R SW 5.6 Forward/Reverse Switch HIGH = Forward LOW = Reverse
16 V
17 V
20 NR SW Noise reduction ON/OFF: HIGH = OFF (2)
21 AMS GIN 1.4 Audio Music Sensor Input Pin
22 AMS OUT Audio Music SensorOutput Pin (open collector configuration, see Fig. 2)
23 GND DIG. 0 Digital Ground

28, 29 IN R

30 EQ SW 0 Equalizer Switch (Low = normal position High = metal position)

(2) Internal pull-up resistor (digital high level if pin left open)

Supply Voltage 12 V

Operating Temperature Range -40 to 85
Storage Temperature Range -40 to 150

,INL

1

2

ref

S Positive Power Supply

ref

,INR

1

2

0 Preamplifier Left Inputs 1,2

Dolby NR Inputs

ref

Dolby Outputs

ref

1.2 Reference Current Source

VS/2 Reference Voltage

0 Preamplifier Right Inputs 1,2

C

°

C

°

2/20

Figure 1: ApplicationCircuit

C13

4.7µF

DOUTR

0.22µFC8

S

V

30K

OUTR

Vs

GND

R12

R10

R8

100K

10K

0.33µF C6(*)

0.68µF (*)

C11

18

TCR

19

AMSout

22

AMSGin

21 23

DINR

24

F/R SW

1.2K

0.68µF C19

NRSW

20

DOLBY

R13

100K

Vs

VREF

17

GND

4.7µF C14

AMS

V

16

S

S

V

BIAS

0.22µF

GND
1

C18

TDA7335

R11

43K 2%

IREF

14

11

MUTE

13

C10

DOUTL

DOLBY

12

TCL

0.68µF

INTS

10

INTP

9

DINL

OUTL

AMSSW

0.33µF C5(*)

EQ SW

8

7

1.2K

GND

Vs

Vs

30K

C16

100nF

C12

4.7µF

R9

100K

R14

C9 1µF

C7 0.1µF

470K R7

C15 10nF

GND

D94AU095B

OUTL

S

V

R15 30K

(*)

6.8K

1.2K

1K

R5

R2

TR2

1µF

C2

0.68µF C17

10nF C4

300K

R6

EQRI EQRO OUTR

15 25

RM RN

27 26

36dB

28INR2

INR1 29

AMP1 AMP2

AMP1 AMP2

36dB

3

INL2

INL1 2

INPUT R

INPUT L

RNRM

C3

10nF

R4

300K

4 5 30 6

EQLI EQLO

R3

R1

TR1

6.8K

1.2K

1K

1µF

C1

C20

0.68µF

(*) Capacitor tolerance is ±10%

3/20

TDA7335

Figure 1a: Components& Top Copper Layer of the Fig. 1 (1:1 scale).

Figure 1b:

Bottom Copper Layer of the Fig. 1 (1:1 scale).

4/20

TEST CIRCUIT

0.22µFC8

OUTR

S

V

R10

R8

4.7µF

100K

10K

C13

0.33µF C6(*)

0.68µF (*)

C11

DOUTR

18

TCR

19

AMSout

22

AMSGin

21 23

DINR

24

F/R SW

1.2K

S

V

NRSW

20

DOLBY

GND

VREF

17

4.7µF C14

AMS

V

16

S

S

V

BIAS

0.22µF

GND
1

C18

TDA7335

R11

43K

IREF

14

11

MUTE

13

C10

DOUTL

DOLBY

12

TCL

(*)

0.68µF

INTS

10

INTP

9

DINL

OUTL

AMSSW

0.33µF C5(*)

EQ SW

8

7

1.2K

C12

4.7µF

R9

100K

S

V

D94AU097A

C9 1µF

C7 0.1µF

470K R7

C15 10nF

OUTL

S

V

6.8K

1.8K

15 25

10nF C4

R5

300K

R2

C2

1µF

R6

EQRI EQRO OUTR

RM RN

27 26

36dB

28INR2

INPUT R

INR1 29

AMP1 AMP2

600Ω

600Ω

300pF

300pF

INL1 2

AMP1 AMP2

3INL2

INPUT L

600Ω

600Ω

36dB

300pF

300pF

RNRM

C3

10nF

R4

300K

4 5 30 6

EQLI EQLO

GND

R3

6.8K

R1

1.8K

C1

1µF

(*) Capacitor tolerance is ±10%

5/20

TDA7335

ELECTRICALCHARACTERISTICS (VS =8.5V;f=1KHz;Rg=600Ω;T

all level referenced to -6dBm/400Hz, at D

out with NR SW OFF; unle ss o t herwise sp ecif ied

=25°C; R11 =43kΩ;

amb

see a pplicat ion circuit of Fig. 1) NAB METAL po sition .

SUPPLY

Symbol Parameter Test Condition Min. Typ. Max. Unit

V

S

I

S

V

ref

DC DC Voltage pin 14 (R11 = 43K) 1.15 1.25 1.35 V

V

SVR Ripple Rejection

MUTE

I

MUTE

MUTE

Supply Voltage 8 8.5 10.5 V
Supply Current 11 18 26 mA
Reference Voltage (pin 17) 4 4.3 4.6 V

(Input referred)
Mute Threshold Pin11 ON

th

V

ripple

f

=1KHz DolbyON

ripple

OFF

80
85

0

2.0

90
95

=0.3Vrms DolbyOFF

Mute Current 10 20
Mute Attenuation 55 65 dB

A

0.8
V

S

PREAMPLIFIER

Symbol Parameter Test Condition Min. Typ. Max. Unit

R

I

I

V Closed Loop Gain pin 4, 5 and 26, 27 shorted 32.5 35.5 38.5 dB

G

G

∆

R

M

R

∆

N Resistance Normal Position 50 160 300 Ω

R

N Total Input Noise Unw.B=20Hzto20KHz;Rg =0Ω

e

R

O Output Impedance (pin 6, 25) 0.9 1.2 1.7 KΩ

F/R

F/R

EQ

EQ

Input Resistance (pin 2, 3, 28, 29) 30 50 70 K

I

Input Bias Current 10

Closed Loop Gain Match -1 1 dB

V

Resistance Metal Position 4.35 5.8 7.25 K
Metal Resistance Matching -2 0 2 dB

M

0.45

R

A weighted; R

l Reverse Low Level(pin 15) IN2 = ON; IN1 = OFF 0 0.8 V

Forward High Level (pin15) IN2= OFF; IN1=ON 2 V

h

NormalLowLevel (pin30) 0 1.5 V

l

MetalHigh Level (pin30) 3.5 V

h

g

=600

g

Ω

=600

Ω

0.8

0.5

S

S

AUDIO MUSIC SENSOR

dB
dB

V
V

µ

µ

µV
µ
µ

V

V

A

Ω

A

Ω

V
V

Symbol Parameter Test Condition Min. Typ. Max. Unit

OUT AMS Output Current 5 mA

IAMS

OUT AMS Output Low Level IAMOUT = 2mA 200 800 mV

VAMS

21 Input Impedance 0.8 1.1 1.4 K

R

P

AMS

AMS

TH1 Interprogram Threshold Voltage (pin9) 1.2 1.45 1.7 V

V

VTH

AMS

IAMS

AMS OFF Low Level 0 0.8 V

swl

AMS ON High Level 2 V

swh

Interspace Threshold Voltage (pin 10) 4 4.3 4.6 V

2

AMS Threshold Level see note (3) 0.6 1 1.4 V

th

AMS Switch pin Current 5 10 15

sw

S

DOLBY SECTION

Symbol Parameter Test Condition DOLBY Min. Typ. Max. Unit

Voltage Gain f = 1KHz; OFF -1 0 1 dB

V Gain Matching OFF -0.5 0.5 dB

Dolby Input Res. (pin 7, 24) 46 63 K

I

6/20

G

∆G

RD

V

Ω

V

A

µ

Ω

TDA7335

ELECTRICALCHARACTERISTICS(continued)
DOLBY SECTION

Symbol Parameter Test Condition DOLBY Min. Typ. Max. Unit

O Dolby Output Impedance (pin 13, 18) 100 200 300 Ω

RD

S/H Signal Handling V
B DEC 1 Decode Out f = 10KHz;V
B DEC 2 Decode Out f = 500Hz;V
B DEC 3 Decode Out f = 2KHz;V
B DEC 4 Decode Out f = 5KHz;V
B DEC 5 Decode Out f = 10KHz;V

NR

NR

DolbyONLow Level Pin20 0 0.8 V

l

Dolby OFF High Level Pin20 2 V

h

GENERAL (PREAMPLIFIER+ DOLBY)

Symbol Parameter Test Condition Min. Typ. Max. Unit

THD Total Harmonic Dist. V

S/N Signal to Noise Ratio R

C

S

C

T

Channel Separation Rg= 600Ω; f = 1KHz Dolby OFF 50 64 dB

Channel Cross Talk Rg= 600Ω; f = 1KHz Dolby OFF 56 70 dB

= 8V; THD = 1% OFF 12 13 dB

S

= 0.4dB ON -1.5 0 1.5 dB

I

= -22.1dB ON -26.5 -25 -23.5 dB

I

= -18dB ON -26.5 -25 -23.5 dB

I
I = -29.7dB ON -41.5 -40 -38.5 dB

= -29.6dB ON -41.5 -40 -38.5 dB

I

S

O = 0dB; f = 1KHz Dolby OFF 0.02 0.1 %
O = 0dB; f = 1KHz Dolby ON 0.05 0.1 %

V

= 0dB; f = 10KHz Dolby OFF 0.03 %

V

O

= 0dB; f = 10KHz Dolby ON 0.08 %

V

O

= 600Ω;VO= 0dB;

g

Unweighted; Dolby OFF
R

= 600Ω;VO= 0dB;

g

Unweighted; Dolby ON
R

=600Ω;VO= 0dB;

g

CCIR/ARM; Dolby OFF
R

=600Ω;VO= 0dB;

g

CCIR/ARM; Dolby ON

g = 600Ω; f = 1KHz Dolby ON 70 dB

R

= 600Ω; f = 1KHz Dolby ON 75 dB

R

g

54 63 dB

56 72 dB

63 dB

70 dB

V

AUDIO MUSIC SENSOR (See Figure2)

Aim of this section is to detect interprogram
spaces present on a recordedtape.

Both the blanks (interprogram spaces) and the
programs minimum detectable durations can be
easily set by means of 2 external and inde­pendent time constants.

Also the minimum detectable input signal level
can be externally adjusted, by a dedicated gain
network.

Main blocks are:

Variablegain limiter amplifier
Signal detector circuitry
Logicblocksableto avoidunproperoperations.

Operations Description (refer to the simplified
schematic ofFigure 2).

a)The two channels left and right mean signal

coming from the preamp chain (AC coupled)
are added (current)at the AMSinput and pre-

sented to the limiter amplifier. The limiter am­plifier gain is internally fixed to 40dB, and it
could be reduced by the R8 external resistor.
The AMSVth threshold is fixed at 1V.The fol­lowing signal detector comparator informs of
the presence of music signal (High level out)
and avoids the erroneous detection of very
low signal (like noise) as real program.

b)The system moves in blank detection mode

everytime the supply is turned on or, with
power supplied, the AMS On/Off pin (to be
driven by an open collector output) is turned

1 open). Once this condition has hap-

off (T
pened, the capacitor C

15 charges, defining a

minimum reset time,long enough to reset the

1

Flip-Flops FF
program detector external C

and FF2and to descharge the

7

capacitor. The
charging current at the AMS SW pin is about
10µA. It follows that the reset time (C

15 x

Vpin8)/IC15 is given approximately by 0.122 x
C15ns where C15is in µF.

7/20

TDA7335

c)From now on where the sum input signal (left-

right) amplified by the limiter exceeds the sig­nal detector threshold (3) the capacitor C
forced to charge. When the voltage across
this capacitor reaches the comparator

1 threshold voltage Vth1 (approx. 2 Vbe)

COMP

1 is set and FF2 is reset. (4) It follows that

FF

1

is turned on discharging the program de-

Q
tectioncapacitor (C

7

).

d)Always when there is a recorded zone, Q

on; it becomes off only if a blank section is
reached. When, with a time constant control­led by the R
space detection time pin reaches V
old (comparator COMP
is detected and the FF

9,C9network the voltage at

th2 thresh-

2) a true blank section

2 is set. (The minimum

chargingtime is approximatelygiven by:

xC9xR9

0.69

In this condition Q

2 is ON, forcing the open

[sec]

collector AMS output to go LOW, informing
the user that a true blank section has been
detected. The state is then able to start from
the above point c). Figures 3-4 show the sig­nal behaviour.

Figure 2:

AudioMusic Sensor

The device is able to prevent false interspace de-

7

Note:

tection and the end of thetape. (see Fig. 4).

is

(3):minimum RMS input signal is given by:

V

=

1K + R

101K + R

right

2

= AMSVth =

V

in

whereV

is

1

in is the mean of left and right channels:

V

in

+ V

left

8

⋅ 0.6

8

(4): the charging current at pin 9 is about 20µA

(half input signal) so program detection time
constantis given by:

2V

x

C

7

be

20µA

= 70 x C

[µF] = [msec]

7

It is recommended to insert a resistor (R7) high
enoughto prevent fast C7 capacitor discharging.

0.22µ
C8

AMS Gin

F

AMS OUT

RB

IN-L

IN-R

1K 100K

21

Rp21 R9

6

+

25

Vth0

POWER-ON

22

Vs

RESET

Q2

-

+

LIMITER

AMPLIFIER

AMS th

Vs

DETECT.

SIGNAL

COMPARATOR

+

-

NOR1

Q1 Vth1

R

COMP2

Vs

­+

108

INTSAMS SW

R9

FF2

Q

S

T1C15 C9

SPACE

DETECTION

TIME

COMP1

Vth2

INTP

9

F C7R7

0.1µ
500K

PROGRAM

DETECTION TIME

SQ

FF1

Q

R

23

T2

D93AU098

8/20

Figure 3: AMS Timing Diagram

TDA7335

Figure 4

9/20

TDA7335

ELECTRICALCOMPONENTDESCRIPTION(seefigure 1)

COMPONENT

TR

,TR

1

C1,C
C3,C4
R1,R
R3,R
R4,R6

C

5,C6

R

8

C

8

2

2

2
5

P
R
E
A

M

P

A

M

S

R
C7

R
C

7

9
9

RECOMMENDED

VALUE

1K

Ω

Left/Right Channel IN/OUT equalizer filter

1µF

10nF

1.2K

6.8K

300KΩ

Ω
Ω

TR fixes thegain
150msec NORMAL
70µsec METAL

0.33µF±10% Preamplifier out to Dolby B input coupling capacitor
Define the AMS input threshold level

10kΩ0.22µF

470KΩ

0.1µF

100K

Ω

1µF

101K + R

V

⋅

in

1K + R
where V
Set the interprogram detection time:

INTP = 70

in

8

=(V

x 10

8

right+Vleft

-3

Set the interspace detection time:
INTS = 0.69

xC9xR9 sec

C15 0.1µF It fixes music search reset time;

Tres = 0.122

C

D

O

L
B
Y

10,C11

C

12,C13

C

14
11 43KΩ It fixes the I

R

16

C
R

16

0.68µF±10% Dolby output coupling capacitors

4.7µF±10% Dolby time constants

4.7µF Reference voltage external capacitor

0.1µF
30K

Ω

If fixes the mute time (typ 10msec).

x C15[µF] = [sec] if C15 expressed in µF

current

ref

⋅1.5 > 1V

)/2

C7[µF] = [sec]

x

PURPOSE

PINS DESCRIPTION

: Internal Configuration

Figure 5: PINS: 2 - 3 - 28 - 29

Figure6: PINS:7 - 24

10/20

PINS DESCRIPTION: InternalConfiguration

TDA7335

Figure 7: PINS: 13 - 18

Figure 9: PINS: 4 - 27

Figure8: PIN:9

Figure10: PINS: 5 - 26

Figure 11: PINS: 6 - 25

Figure12: PINS: 8 - 15

11/20

TDA7335

PINS DESCRIPTION: InternalConfiguration
Figure 13: PINS: 12 - 19

Figure 15: PIN: 10

Figure14: PIN: 14

Figure16: PIN: 22

Figure 17: PIN: 21

12/20

Figure18: PIN: 30

PINS DESCRIPTION: InternalConfiguration

TDA7335

Figure 19: PIN: 20 - 11

DEVICECHARACTERISTICS

Figure 21: QuiescentCurrent vs. Supply Voltage

Figure20: PIN: 17

Figure22:

QuiescentCurrent vs. Temperature

Figure 23:

THDvs Supply Voltage

Figure24: THDvs Frequency

13/20

TDA7335

DEVICECHARACTERISTICS (continued)
Figure 25: THD vs. Output Signal

Figure 27:

ChannelSeparationvs. Frequency

Figure26: THD+ N vs. Frequency

Figure28:

CrossTalk vs. Frequency

Figure 29:

14/20

RippleRejection vs. Frequency

Figure30: Ripple Rejection vs. Frequency

TDA7335

DEVICECHARACTERISTICS (continued)
Figure 31: Ripple Rejectionvs. Frequency

Figure 33:

MuteThreshold

Figure32: Mute Attenuationvs. Frequency

Figure34: V

ref.&Iref.

vs. V

supply

Figure 35:

V

ref.&Iref.

vs.Temperature

Figure36: D.C. Voltagepin 14vs. V

supply

15/20

TDA7335

DEVICECHARACTERISTICS (continued)
Figure 37:

EqualizerThreshold

Figire 38: Forward/ReverseThreshold

Figure 39:

Figure 41:

NoiseReduction Threshold

SignalHandling vs. V

supply

Figure40: Load Characteristcs

Figure42: Signalhandling vs. Temperature

16/20

DEVICECHARACTERISTICS (continued)
Figure 43:

AMSThresholdvs. Frequency

Figure44: AMSThreshold vs. R

TDA7335

ex

Figure 45:

Figure 47:

AMSReset Time vs. C

ex

InterprogramCharging Current

Figure46: AMSInterprogram vs. C7

Figure48: Interspacevs. C9

17/20

TDA7335

DEVICECHARACTERISTICS (continued)
Figure 49: NABNetwork

Figure50: Dolby-BTable

Normal

Metal

18/20

TDA7335

DIM.

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

A 5.08 0.20
A1 0.51
A2 3.05 3.81 4.57 0.12 0.15 0.18

B 0.36 0.46 0.56 0.014 0.018 0.022
B1 0.76 0.99 1.40 0.030 0.039 0.055

C 0.20 0.25 0.36 0.008 0.01 0.014
D 27.43 27.94 28.45 1.08 1.10 1.12

E 10.16 10.41 11.05 0.400 0.410 0.435
E1 8.38 8.64 9.40 0.330 0.340 0.370

e 1.778 0.070

e1 10.16 0.400

L 2.54 3.30 3.81 0.10 0.13 0.15

M0°(min.),15°(max.)

S 0.31 0.012

mm inch

0.020

OUTLINE AND

MECHANICAL DATA

SDIP30 (0.400”)

19/20

TDA7335

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20/20