DIGITALLY CONTROLLED AUDIO PROCESSOR
INPUTMULTIPLEXER
- 2 STEREO INPUTS
- SELECTABLEINPUT GAIN FOR OPTIMAL
ADAPTATIONTO DIFFERENT SOURCES
ONE STEREO OUTPUT
VOLUMECONTROL IN 1.0dB STEPS
TWOSPEAKERATTENUATORS:
- TWOINDEPENDENTSPEAKERCONTROL
IN 1.0dBSTEPS FOR BALANCEFACILITY
- INDEPENDENTMUTE FUNCTION
ALL FUNCTION ARE PROGRAMMABLE VIA
SERIALBUS
DESCRIPTION
The TDA7449L is a volume control and balance
(Left/Right) processor for quality audio applications in TV systems.
Selectable input gain is provided. Control of all
the functions is accomplishedby serialbus.
The AC signal setting is obtained by resistor net-
TDA7449L
LOW COST
DIP20
ORDERING NUMBER: TDA7449L
works and switches combined with operational
amplifiers.
Thanks to the used BIPOLAR/CMOSTechnology,
Low Distortion, Low Noise and DC stepping are
obtained.
BLOCK DIAGRAM
L-IN1
L-IN2
R-IN1
R-IN2
MUXOUTL
8
100K
9
100K
7
100K
6
100K
INPUT
G
0/30dB
2dB STEP
G
MULTIPLEXER
+ GAIN
10
VOLUME
I2CBUS DECODER + LATCHES
VOLUME
11 1
MUXOUTR
SPKR ATT
LEFT
SPKR ATT
RIGHT
V
REF
SUPPLY
CREF
5
19
20
18
4
2
3
LOUT
SCL
SDA
DIG_GND
ROUT
V
S
AGND
D98AU868
April 1999
1/13
TDA7449L
ABSOLUTE MAXIMUM RATINGS
Symbol Parameter Value Unit
V
S
T
amb
T
stg
PIN CONNECTION
Operating Supply Voltage 10.5 V
Operating Ambient Temperature -10 to 85 °C
Storage Temperature Range -55 to 150 °C
CREF
V
PGND
ROUT
LOUT
R_IN2
R_IN1
L_IN1
L_IN2
1
2
S
3
4
5
6
7
8
9 N.C.
19
18
17
16
15
14
13
12
SDA20
SCL
DIG_GND
N.C.
N.C.
N.C.
N.C.
N.C.
MUXOUT(L) 10 MUXOUT(R)11
D98AU869
THERMAL DATA
Symbol Parameter Value Unit
R
thj-pin
Thermal ResistanceJunction-pins 150 °C/W
QUICK REFERENCE DATA
Symbol Parameter Min. Typ. Max. Unit
V
S
V
CL
THD Total Harmonic DistortionV = 1Vrms f = 1KHz 0.01 0.1 %
S/N Signal to Noise Ratio V
S
C
2/13
Supply Voltage 6 9 10.2 V
Max. input signal handling 2 Vrms
= 1Vrms (mode = OFF) 106 dB
out
Channel Separation f = 1KHz 90 dB
Input Gain in (2dBstep) 0 30 dB
Volume Control (1dB step) -47 0 dB
Balance Control 1dB step -79 0 dB
Mute Attenuation 100 dB
TDA7449L
ELECTRICALCHARACTERISTICS
R
= 600Ω, all controls flat (G = 0dB), unless otherwise specified)
G
(refer to the test circuit T
=25°C,VS= 9V,RL= 10KΩ,
amb
Symbol Parameter Test Condition Min. Typ. Max. Unit
SUPPLY
V
S
I
S
SVR Ripple Rejection 60 90 dB
Supply Voltage 6 9 10.2 V
Supply Current 7 mA
INPUT STAGE
G
G
R
V
S
inmin
inman
G
IN
CL
IN
step
Input Resistance 100 KΩ
Clipping Level THD = 0.3% 2 2.5 Vrms
Input Separation The selected input is grounded
80 100 dB
through a 2.2µ capacitor
Minimum Input Gain -1 0 1 dB
Maximum Input Gain 30 dB
Step Resolution 2 dB
VOLUMECONTROL
C
RANGE
A
A
V
A
VMAX
STEP
E
A
E
T
DC
mute
Control Range 45 47 49 dB
Max. Attenuation 45 47 49 dB
Step Resolution 0.5 1 1.5 dB
Attenuation Set Error AV= 0 to-24dB -1.0 0 1.0 dB
A
= -24 to -47dB -1.5 0 1.5 dB
V
Tracking Error AV= 0 to-24dB 0 1 dB
= -24 to -47dB 0 2 dB
A
V
DC Step adjacent attenuation steps
from 0dB to A
V
max
0
0.5
3mV
Mute Attenuation 80 100 dB
SPEAKERATTENUATORS
C
RANGE
S
V
A
STEP
E
A
DC
mute
Control Range 76 dB
Step Resolution 0.5 1 1.5 dB
Attenuation Set Error AV= 0 to-20dB -1.5 0 1.5 dB
A
= -20 to -56dB -2 0 2 dB
V
DC Step adjacent attenuation steps 0 3 mV
Mute Attenuation 80 100 dB
AUDIO OUTPUTS
V
CLIP
R
L
R
O
V
DC
Clipping Level d = 0.3% 2.1 2.6 V
Output Load Resistance 2 KΩ
Output Impedance 10 40 70
DC Voltage Level 3.8 V
mV
RMS
Ω
GENERAL
E
NO
E
S/N Signal to Noise Ratio Allgains 0dB; V
S
C
d Distortion A
Output Noise All gains = 0dB;
BW = 20Hz to 20KHz flat
Total TrackingError AV= 0 to-24dB 0 1 dB
t
A
= -24 to -47dB 0 2 dB
V
Channel Separation Left/Right 80 100 dB
=0;VI=1V
V
BUS INPUT
515µV
O =1VRMS ; 106 dB
; 0.01 0.08 %
RMS
3/13
TDA7449L
ELECTRICALCHARACTERISTICS
(continued.)
Symbol Parameter Test Condition Min. Typ. Max. Unit
BUS INPUT
V
IL
V
IH
I
IN
V
O
Input Low Voltage 1V
Input High Voltage 3 V
Input Current VIN= 0.4V -5 5
Output Voltage SDA
IO = 1.6mA 0.4 0.8 V
Acknowledge
TEST CIRCUIT
MUXOUTL
10
8
L-IN1
0.47µF
L-IN2
0.47µF
R-IN1
0.47µF
100K
9
100K
7
100K
G
0/30dB
2dB STEP
VOLUME
I2CBUS DECODER + LATCHES
SPKR ATT
LEFT
19
20
18
5
LOUT
SCL
SDA
DIG_GND
A
µ
6
R-IN2
0.47µF
100K
INPUT MULTIPLEXER
G
+ GAIN
APPLICATIONSUGGESTIONS
The first and the last stages are volume control
blocks. The control range is 0 to -47dB (mute) for
the first one, 0 to -79dB (mute) for the last one.
Both of them have 1dB step resolution.
The very high resolutionallows the implementation
of systemsfreefromanynoisyacousticaleffect.
10µF
4
2
3
D98AU870
ROUT
V
S
AGND
VOLUME
11 1
MUXOUTR
SPKR ATT
RIGHT
V
REF
SUPPLY
CREF
The TDA7449L audioprocessor provides 2 bands
tonescontrol.
CREF
The suggested 10µF reference capacitor (CREF)
value can be reduced to 4.7µF if the application
requiresfasterpower ON.
4/13
TDA7449L
Figure 2:
Figure 4:
THD vs. frequency
Channelseparationvs. frequency
Figure3:
THDvs. R
LOAD
5/13
TDA7449L
2
C BUS INTERFACE
I
Data transmission from microprocessor to the
TDA7449L and vice versa takes place through
the 2 wires I
2
C BUS interface, consisting of the
two lines SDA and SCL (pull-up resistors to positive supply voltage must be connected).
Data Validity
As shown in fig. 3, thedata on the SDA line must
be stable during the high period of the clock. The
HIGH and LOW state of the data line can only
change when the clock signal on the SCL line is
LOW.
Start and Stop Conditions
As shown in fig.4 a start condition is a HIGH to
LOW transition of the SDA line while SCL is
HIGH. The stop condition is a LOW to HIGH transition of the SDA line while SCL is HIGH.
Byte Format
Every byte transferred on the SDA line must contain 8 bits. Each byte must be followed by an ac-
Figure 3:
Data Validityon theI
2
CBUS
knowledgebit. The MSB is transferredfirst.
Acknowledge
The master (µP)puts a resistiveHIGH level on the
SDA line during the acknowledgeclock pulse (see
fig. 5). The peripheral (audio processor) that acknowledges has to pull-down (LOW) the SDA line
duringthisclock pulse.
The audio processor which has been addressed
has to generate an acknowledge after the reception of each byte, otherwise the SDAline remains
at the HIGH level during the ninth clock pulse
time. In this case the master transmitter can generate the STOP information in order to abort the
transfer.
Transmissionwithout Acknowledge
Avoiding to detect the acknowledge of the audio
processor,the µP canuse a simplertransmission:
simply it waits one clock without checking the
slaveacknowledging,and sends the new data.
This approach of course is less protected from
misworking.
Figure 4:
TimingDiagram of I
2
Figure 5: Acknowledgeon the I
6/13
CBUS
2
CBUS
TDA7449L
SOFTWARESPECIFICATION
InterfaceProtocol
The interface protocol comprises:
A start condition (S)
address
A subaddressbytes
A sequenceof data (N byte + acknowledge)
A stopcondition (P)
A chip addressbyte, containingthe TDA7449L
CHIP ADDRESS
MSB LSB MSB LSB MSB LSB
S10001000ACK ACK DATA ACK P
D96AU420
SUBADDRESS DATA 1 to DATA n
X DATA
XXB
ACK = Acknowledge
S = Start
P = Stop
A = Address
B = Auto Increment
EXAMPLES
No IncrementalBus
rect chip address, a subaddress with the B = 0
(no incremental bus), N-data (all these data concern the subaddressselected),a stop condition.
The TDA7449L receives a startcondition,the cor-
CHIP ADDRESS
MSB LSB MSB LSB MSB LSB
S10001000ACK ACK DATA ACK P
D96AU421
IncrementalBus
The TDA7449L receive a start conditions, the
correct chip address, a subaddresswith the B = 1
(incremental bus): now it is in a loop condition
with an autoincreaseof the subaddress whereas
CHIP ADDRESS
MSB LSB MSB LSB MSB LSB
S10001000ACK ACK DATA ACK P
D96AU422
SUBADDRESS DATA
XD3
XX0 D2D1D0
SUBADDRESS from ”XXX1000” to ”XXX1111”of
DATAare ignored.
The DATA 1 concern the subaddress sent, and
the DATA 2 concern the subaddress sent plus
one in the loop etc, and at the end it receivers the
stop condition.
SUBADDRESS DATA 1 to DATA n
XD3
XX1 D2D1D0
7/13
TDA7449L
POWERON RESET CONDITION
INPUT SELECTION IN2
INPUT GAIN 28dB
VOLUME MUTE
SPEAKER MUTE
DATA BYTES
Address = 88 HEX (ADDR:OPEN).
FUNCTIONSELECTION:First byte (subaddress)
MSB LSB
D7 D6 D5 D4 D3 D2 D1 D0
XXXB00 00INPUT SELECT
XXXB00 01INPUT GAIN
XXXB00 10VOLUME
XXXB00 11NOTUSED
XXXB01 00NOTUSED
XXXB01 01NOTUSED
XXXB01 10SPEAKER ATTENUATE ”R”
XXXB01 11SPEAKER ATTENUATE ”L”
B = 1: INCREMENTAL BUSACTIVE
B = 0: NO INCREMENTALBUS
X = DON’T CARE
SUBADDRESS
In IncrementalBus Mode, the three ”not used” functions must be addressedin any case. For example to
refresh ”Volume= 0dB”and Speaker_R= -40dB”,the followingbytes mustbe sent:
SUBADDRESS XXX10010
VOLUME DATA X0000000
NOT USED 1 DATA XXXX1111
NOT USED 2 DATA XXXX1111
NOT USED 3 DATA XXXX1111
SPEAKER_R DATA X0000010
INPUT SELECTION
MSB LSB
D7 D6 D5 D4 D3 D2 D1 D0
XXXXXX00 NOTALLOWED
XXXXXX01 NOTALLOWED
XXXXXX10 IN2
XXXXXX11 IN1
8/13
INPUT MULTIPLEXER
DATA BYTES (continued)
INPUT GAIN SELECTION
MSB LSB INPUT GAIN
D7 D6 D5 D4 D3 D2 D1 D0 2dB STEPS
0000 0dB
0001 2dB
0010 4dB
0011 6dB
0100 8dB
0 1 0 1 10dB
0 1 1 0 12dB
0 1 1 1 14dB
1 0 0 0 16dB
1 0 0 1 18dB
1 0 1 0 20dB
1 0 1 1 22dB
1 1 0 0 24dB
1 1 0 1 26dB
1 1 1 0 28dB
1 1 1 1 30dB
TDA7449L
GAIN = 0 to 30dB
VOLUMESELECTION
MSB LSB VOLUME
D7 D6 D5 D4 D3 D2 D1 D0 1dB STEPS
0 0 0 0dB
0 0 1 -1dB
0 1 0 -2dB
0 1 1 -3dB
1 0 0 -4dB
1 0 1 -5dB
1 1 0 -6dB
1 1 1 -7dB
0000 0dB
0 0 0 1 -8dB
0 0 1 0 -16dB
0 0 1 1 -24dB
0 1 0 0 -32dB
0 1 0 1 -40dB
X 1 1 1 X X X MUTE
VOLUME = 0 to 47dB/MUTE
9/13
TDA7449L
DATA BYTES (continued)
SPEAKERATTENUATE SELECTION
MSB LSB SPEAKER ATTENUATION
D7 D6 D5 D4 D3 D2 D1 D0 1dB
0 0 0 0dB
0 0 1 -1dB
0 1 0 -2dB
0 1 1 -3dB
1 0 0 -4dB
1 0 1 -5dB
1 1 0 -6dB
1 1 1 -7dB
0000 0dB
0 0 0 1 -8dB
0 0 1 0 -16dB
0 0 1 1 -24dB
0 1 0 0 -32dB
0 1 0 1 -40dB
0 1 1 0 -48dB
0 1 1 1 -56dB
1 0 0 0 -64dB
1 0 0 1 -72dB
1 1 1 1 X X X MUTE
SPEAKER ATTENUATION = 0 to-79dB/MUTE
PIN: 1
V
S
V
S
20K
CREF
20K
D96AU430
PINS: 4,5
ROUT
LOUT
D96AU434
V
S
24
20µA
10/13
TDA7449L
PINS: 6,7,8,9
V
S
IN
PIN:
19
PINS: 10,11
V
S
20µA
MUXOUT
100K
V
REF
D96AU425
PIN:
20
20µA
V
S
20µA
GND
D96AU491
20µA
SCL
SDA
D96AU423
D96AU424
11/13
TDA7449L
DIM.
MIN. TYP. MAX. MIN. TYP. MAX.
a1 0.254 0.010
B 1.39 1.65 0.055 0.065
b 0.45 0.018
b1 0.25 0.010
D 25.4 1.000
E 8.5 0.335
e 2.54 0.100
e3 22.86 0.900
F 7.1 0.280
I 3.93 0.155
L 3.3 0.130
Z 1.34 0.053
mm inch
OUTLINE AND
MECHANICAL DATA
DIP20
12/13
TDA7449L
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of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is
granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specification mentioned in this publication are
subject to change without notice. This publicationsupersedes and replaces all informationpreviously supplied. STMicroelectronics products
are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics.
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13/13
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