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TDA7449
一年级孩子June 2004
1我无法忘记你
FEATURES
■
INPUT MULTIPLEXER –2 STEREO INPUTS
–SELECTABLE INPUT GAIN FOR OPTIMAL ADAPTATION TO DIFFERENT SOURCES
■ONE STEREO OUTPUT
■
TREBLE, AND BASS CONTROL IN 2.0dB STEPS
■VOLUME CONTROL IN 1.0dB STEPS ■
TWO SPEAKER ATTENUATORS:
–TWO INDEPENDENT SPEAKER CONTROL IN 1.0dB STEPS FOR BALANCE FACILITY –INDEPENDENT MUTE FUNCTION
■
ALL FUNCTION ARE PROGRAMMABLE VIA SERIAL BUS
2DESCRIPTION
The TDA7449 is a volume tone (bass and treble)balance (Left/Right) processor for quality audio applications in TV systems. Selectable input gain is provided. Control of all the functions is accom-plished by rial bus.
荆门美食
The AC signal tting is obtained by resistor net-works and switches combined with operational amplifiers.
Thanks to the ud BIPOLAR/CMOS Technology,Low Distortion, Low Noi and DC stepping are obtained.
TONE CONTROL
DIGITALLY CONTROLLED AUDIO PROCESSOR
Figure 2. Block Diagram
REV. 4Figure 1. Package
Table 1. Order Codes
Part Number Package TDA7449DIP20TDA7449D
SO20
TDA7449
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Table 2. Absolute Maximum Ratings
Figure 3. Pin Connection
Table 3. Thermal Data
Table 4. Quick Reference Data
Symbol Parameter
Value Unit V S Operating Supply Voltage 10.5V T amb Operating Ambient Temperature 0 to 70°C T stg
Storage Temperature Range
-55 to 150
°C
Symbol Parameter
Value Unit R th j-pin
Thermal Resistance Junction- pins
85
°C/W
Symbol Parameter
Min.Typ.Max.Unit V S Supply Voltage
69
10.2
V V CL Max Input Signal Handling
2
V RMS THD Total Harmonic Distortion V = 0.1Vrms f = 1KHz 0.010.1
%S/N Signal to Noi Ratio V out = 1Vrms (mode = OFF)106dB S C
Channel Separation f = 1KHz 90
dB Input Gain (2dB step)030dB Volume Control (1dB step)-470dB Treble Control (2dB step)-1414dB Bass Control (2dB step)
-1414dB Balance Control 1dB step -79
旧房改造政策
0dB Mute Attenuation
100
dB
TDA7449 Table 5. Electrical Characteristcs (refer to the test circuit T amb = 25°C, V S = 9V, R L= 10KΩ, R G = 600Ω, all controls flat (G = 0dB), unless otherwi specified)
Symbol Parameter Test Condition Min.Typ.Max.Unit SUPPLY
V S Supply Voltage6910.2V
I S Supply Current7mA
SVR Ripple Rejection6090dB INPUT STAGE
R IN Input Resistance100KΩV CL Clipping Level THD = 0.3%2 2.5Vrms
80100dB S IN Input Separation The lected input is grounded
through a 2.2µ capacitor
G inmin Minimum Input Gain-101dB
G inman Maximum Input Gain30dB
G step Step Resolution2dB VOLUME CONTROL
C RANGE Control Range454749dB
A VMAX Max. Attenuation454749dB
A STEP Step Resolution0.51 1.5dB
E A Attenuation Set Error A V = 0 to -24dB-1.00 1.0dB
丰田生产模式
A V = -24 to -47dB-1.50 1.5dB
E T Tracking Error A V = 0 to -24dB01dB
A V = -24 to -47dB02dB
V DC DC Step adjacent attenuation steps03mV
from 0dB to A V max0.5mV
A mute Mute Attenuation80100d
B BASS CONTROL (1)
Gb Control Range Max. Boost/cut+12.0+14.0+16.0dB
B STEP Step Resolution123dB
R B Internal Feedback Resistance18.752531.25KΩTREBLE CONTROL (1)
Gt Control Range Max. Boost/cut+13.0+14.0+15.0dB T STEP Step Resolution123dB
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TDA7449
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Note: 1.The device is functionally good at Vs = 5V. a step down, on Vs, to 4V does’t ret the device.
2.BASS and TREBLE respon: The center frequency and the respon quality can be chon by the external circuitry.
SPEAKER ATTENUATORS
C RANGE Control Range 76dB S STEP Step Resolution 0.51 1.5dB E A
Attenuation Set Error
A V = 0 to -20d
B -1.50 1.5dB A V = -20 to -56dB
-2
02dB V DC DC Step adjacent attenuation steps
03
mV A mute
Mute Attenuation
80100
dB
AUDIO OUTPUTS
V CLIP Clipping Level
d = 0.3%
2.1 2.6
V RMS R L Output Load Resistance 2K ΩR O Output Impedance 10
4070
W V DC
DC Voltage Level
3.8
V
GENERAL
E NO Output Noi All gains = 0dB;
BW = 20Hz to 20KHz flat 515µV E t
Total Tracking Error
A V = 0 to -24d
B 01dB A V = -24 to -47dB
02
dB S/N Signal to Noi Ratio
All gains 0dB; V O = 1V RMS ;
106dB S C Channel Separation Left/Right 80
100dB d
Distortion
A V = 0; V I = 1V RMS ;0.01
0.08%
BUS INPUT
V IL Input Low Voltage 1
V V IH Input High Voltage 3V I IN Input Current V IN = 0.4V -5
5µA V O
Output Voltage SDA Acknowledge
I O = 1.6mA唐朝
0.4
0.8V
Table 5. Electrical Characteristcs (continued)
TDA7449 Figure 4. P.C.Board (Referred to DIP20 package only)
Figure 5. Test Circuit
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cslr
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TDA7449
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3APLICATION SUGGESTIONS
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 resolution allows the implementation of systems free from any noisy acoustical effect. The TDA7449 audioprocessor provides 2 bands tones control.
3.1Bass, Stages
The Bass cell has an internal resistor Ri = 25K Ω typical. Several filter types can be implemented, co
nnect-ing external components to the Bass IN and OUT pins. The fig.6 refers to basic T Type Bandpass Filter starting from the filter component values (R1 internal Fc, the gain Av at max. boost and the filter Q factor are computed as follows:Figure 6.
Viceversa, once Fc, Av, and Ri internal value are fixed, the external components values will be:
3.2Treble Stage
The treble stage is a high pass filter who time constant is fixed by an internal resistor (25K Ω typical) and an external capacitor connected between treble pins and ground Typical respons are reported in Figg.10 to 13.
3.3CREF
The suggested 10µF reference capacitor (CREF) value can be reduced to 4.7µF if the application requires faster power ON.
F C 1
2πR1R2C1C2
⋅⋅⋅⋅⋅-----------------------------------------------------------------=A V R2C2R2C1RiC1++R2C1R2C2
+------------------------------------------------------------=Q R1R2C1C2
⋅⋅⋅R2C1R2C2
+-------------------------------------------------=C1A V 1–2πFc Ri Q ⋅⋅⋅⋅------------------------------------------ C2Q 2C1
⋅A V 1–Q
2–-----------------------------==R2A V 1–Q
2
–2πC1Fc A V 1–()Q
⋅⋅⋅⋅⋅----------------------------------------------------------------------=
