1) The device is functionally goodat Vs = 5V. a step down,on Vs, to 4V does’t reset thedevice.
2) BASS,MIDDLE and TREBLEresponse: The center frequency and theresponse quality can be chosen by the external circuitry.
Control Range707682dB
Step Resolution0.511.5dB
Attenuation Set ErrorAV= 0 to-20dB-1.501.5dB
A
= -20 to -56dB-202dB
V
DC Stepadjacent attenuation steps03mV
Mute Attenuation80100dB
Ω
mV
Ω
4/19
TDA7439
ELECTRICALCHARACTERISTICS (continued.)
SymbolParameterTest ConditionMin.Typ.Max.Unit
AUDIOOUTPUTS
V
CLIP
R
L
R
O
V
DC
GENERAL
E
NO
E
t
S/NSignal to Noise RatioAll gains 0dB; V
S
C
dDistortionA
BUS INPUT
V
IL
V
IH
I
INInput CurrentVIN = 0.4V-505µA
V
O
Clipping Leveld = 0.3%2.12.6V
Output Load Resistance2KΩ
Output Impedance104070
DC Voltage Level3.53.84.1V
Output NoiseAll gains = 0dB;
515
BW = 20Hz to 20KHz flat
Total Tracking ErrorAV= 0to -24dB01dB
= -24to -47dB02dB
A
V
O
=1V
;95106dB
RMS
Channel Separation Left/Right80100dB
V =0;VI=1VRMS ;0.010.08%
Input Low Voltage1V
Input High Voltage3V
Output Voltage SDA
IO= 1.6mA0.40.8V
Acknowledge
RMS
Ω
V
µ
TEST CIRCUIT
L-IN1
0.47µF
L-IN2
0.47µF
L-IN3
0.47µF
L-IN4
0.47µF
R-IN1
0.47µF
R-IN2
0.47µF
R-IN3
0.47µF
R-IN4
0.47µF
5.6nF
2.2µF
11
100K
12
100K
13
100K
14
100K
10
100K
9
100K
8
100K
7
100K
INPUT MULTIPLEXER
MUXOUTLINL
G
0/30dB
2dB STEP
G
+ GAIN
MUXOUTRINR TREBLE(R)
TREBLE(L)
15162726252324
VOLUME
VOLUME
171828192021222
2.2µF
5.6nF
2.7K5.6K
18nF22nF 100nF100nF
MIN(L)
MOUT(L)
R
M
TREBLE
TREBLE
MIDDLE
I2CBUS DECODER + LATCHES
MIDDLE
R
M
MOUT(R)BOUT(R)BIN(R)
MIN(R)
18nF22nF 100nF100nF
2.7K5.6K
BIN(L)
BASS
BASS
BOUT(L)
R
B
SPKR ATT
LEFT
SPKR ATT
RIGHT
V
REF
R
SUPPLY
B
CREF
10µF
30
29
6
1
5
3
4
LOUT
SCL
SDA
DIGGND
ROUT
V
S
AGND
D95AU339B
5/19
TDA7439
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.
The TDA7439 audioprocessor provides 3 bands
tones control.
Bass, Middle Stages
The Bass and the middle cells have the same
structure.
The Bass cell has an internal resistor Ri = 44KΩ
typical.
The Middle cell has an internalresistor Ri = 25KΩ
typical.
Several filter types can be implemented, connecting external components to the Bass/Middle IN
and OUTpins.
Figure 1.
Ri internal
OUTIN
C
1
R
2
D95AU313
C
2
The fig.1 refers to basic T Type Bandpass Filter
starting from the filter component values (R1 internal and R2,C1,C2 external) the centre frequency Fc, the gain Av at max. boost and the filter Q factorare computedas follows:
=
F
C
1
2 ⋅ π ⋅√R1 ⋅ R2 ⋅ C1 ⋅ C2
R2 C2 + R2 C1 + RiC1
A
=
V
R2 C1 + R2 C2
√R1 ⋅ R2 ⋅ C1 ⋅ C2
Q =
R2 C1 + R2 C2
Viceversa, once Fc, Av, and Ri internal value are
fixed, the external componentsvalues will be:
C1 =
− 1
A
V
2 ⋅ π ⋅ F
R2 =
⋅ Ri⋅ Q
C
A
− 1 − Q
V
2 ⋅ π ⋅ C1 ⋅ FC⋅ (AV− 1) ⋅Q
C2 =
2
Q
A
V
2
⋅ C1
− 1 − Q
2
TrebleStage
The treble stage is a high pass filter whose time
constant is fixed by an internal resistor (25KΩ
typical) and an external capacitor connected between treble pins andground
Typical responsesare reported in Figg. 10 to 13.
CREF
The suggested 10µF reference capacitor (CREF)
value can be reduced to 4.7µF if the application
requiresfasterpower ON.
Figure 2:
6/19
THD vs. frequency
Figure3:
THDvs. R
LOAD
TDA7439
Figure 4: Channelseparationvs. frequency
Figure 6: Middleresponse
=25k
R
Ω
i
C9= 15nF (MIN)
C6- 22nF (MOUT)
R1 = 2.7k
Ω
Figure5: Bassresponse
Figure7:
Trebleresponse
Ri= 44kΩ
C9 = C10 = 100nF (Bout,Bin)
R3 = 5.6k
Ω
Figure 8: Typicaltone response
7/19
TDA7439
I2C BUSINTERFACE
Data transmission from microprocessor to the
TDA7439 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. 9, 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.10 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-
2
Figure 9: Data Validityon theI
CBUS
knowledgebit. The MSB is transferredfirst.
Acknowledge
The master (µP)puts a resistiveHIGH level on the
SDA line during the acknowledgeclock pulse (see
fig. 11). 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 10:
TimingDiagram of I
2
Figure 11: Acknowledgeon the I
8/19
CBUS
2
CBUS
TDA7439
SOFTWARESPECIFICATION
InterfaceProtocol
The interface protocol comprises:
A start condition (S)
address
A subaddressbytes
A sequenceof data (N byte + acknowledge)
A stopcondition (P)
A chip address byte, containing the TDA7439
CHIP ADDRESS
MSBLSBMSBLSBMSBLSB
S10001000ACKACKDATAACKP
D96AU420
SUBADDRESSDATA 1 to DATA n
XDATA
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 TDA7439 receives a start condition, the cor-
CHIP ADDRESS
MSBLSBMSBLSBMSBLSB
S10001000ACKACKDATAACKP
D96AU421
IncrementalBus
The TDA7439 receive a start conditions, the correct chip address, a subaddress with the B = 1
(incremental bus): now it is in a loop condition
with an autoincreaseof the subaddress whereas
CHIP ADDRESS
MSBLSBMSBLSBMSBLSB
S10001000ACKACKDATAACKP
D96AU422
SUBADDRESSDATA
XD3
XX0D2D1D0
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.
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences
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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