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(R)
TDA7438
THREE BANDS DIGITALLY CONTROLLED AUDIO PROCESSOR
INPUT MULTIPLEXER - 3 STEREO INPUTS - SELECTABLE INPUT GAIN FOR OPTIMAL ADAPTATION TO DIFFERENT SOURCES ONE STEREO OUTPUT TREBLE, MIDDLE 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 DESCRIPTION The TDA7438 is a volume tone (bass, middle and treble) balance (Left/Right) processor for quality audio applications in car-radio and Hi-Fi systems. Selectable input gain is provided. Control of all the functions is accomplished by serial bus. BLOCK DIAGRAM
MUXOUTL L-IN1 3 100K 4 100K 5 100K G VOLUME TREBLE 6 INL 7 TREBLE(L) 18
SO28
DIP28
ORDERING NUMBER: TDA7438D (SO28) TDA7438 (DIP28)
The AC signal setting is obtained by resistor networks and switches combined with operational amplifiers. Thanks to the used BIPOLAR/CMOS Technology, Low Distortion, Low Noise and DC stepping are obtained.
MIN(L) MOUT(L) BIN(L) 17 RM 16 14 RB
BOUT(L) 15
L-IN2
L-IN3
MIDDLE
BASS
SPKR ATT LEFT
27
LOUT
R-IN1
2 100K 1 100K 28
0/30dB 2dB STEP
21 I2CBUS DECODER + LATCHES 22 20
SCL SDA DIG_GND
R-IN2
G
VOLUME
TREBLE
MIDDLE
BASS
SPKR ATT RIGHT V REF
26
ROUT
R-IN3
100K 24 INPUT MULTIPLEXER + GAIN 8 MUXOUTR 9 INR 19 TREBLE(R) 10 SUPPLY RM 11 12 RB 13 23
D96AU488A
25
VS AGND
MIN(R) MOUT(R) BIN(R)
BOUT(R) CREF
April 1999
1/17
TDA7438
ABSOLUTE MAXIMUM RATINGS
Symbol VS Tamb Tstg Operating Supply Voltage Operating Ambient Temperature Storage Temperature Range Parameter Value 10.5 -10 to 85 -55 to 150 Unit V C C
PIN CONNECTION
R_IN2 R_IN1 L_IN1 L_IN2 L_IN3 MUXOUTL INL MUXOUTR INR MIN(R) MOUT(R) BIN(R) BOUT(R) BIN(L) 1 2 3 4 5 6 7 8 9 10 11 12 13 14
D96AU489A
28 27 26 25 24 23 22 21 20 19 18 17 16 15
R_IN3 LOUT ROUT AGND VS CREF SDA SCL DIG-GND TREBLE(R) TREBLE(L) MIN(L) MOUT(L) BOUT(L)
THERMAL DATA
Symbol R th j-pin Parameter Thermal Resistance Junction-pins Value 85 Unit C/W
QUICK REFERENCE DATA
Symbol VS VCL THD S/N SC Supply Voltage Max. input signal handling Total Harmonic Distortion V = 1Vrms f = 1KHz Signal to Noise Ratio V out = 1Vrms (mode = OFF) Channel Separation f = 1KHz Input Gain in (2dB step) Volume Control Treble Control (1dB step) (2dB step) 0 -47 -14 -14 -14 -79 80 100 Parameter Min. 6 2 0.01 106 90 30 0 +14 +14 +14 0 0.1 Typ. 9 Max. 10.2 Unit V Vrms % dB dB dB dB dB dB dB dB dB
Middle Control (2dB step) Bass Control (2dB step) Balance Control 1dB step Mute Attenuation (*)
(*) Even applied to Speaker Attenuator Left, Speaker Attenuator Right, Volume Control stand alone or to the combination, if any.
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TDA7438
ELECTRICAL CHARACTERISTICS (refer to the test circuit Tamb = 25C, VS = 9V, RL= 10K, RG = 600, all controls flat (G = 0dB), unless otherwise specified)
Symbol Parameter Test Condition Min. Typ. Max. Unit
SUPPLY
VS IS SVR Supply Voltage Supply Current Ripple Rejection 6 60 9 7 90 10.2 V mA dB
INPUT STAGE
RIN VCL SIN Ginmin Ginman Gstep Input Resistance Clipping Level Input Separation Minimum Input Gain Maximum Input Gain Step Resolution THD = 0.3% The selected input is grounded through a 2.2 capacitor 2 80 -1 100 2.5 100 0 30 2 1 K Vrms dB dB dB dB
VOLUME CONTROL
Ri CRANGE AVMAX ASTEP EA ET VDC Amute Gb BSTEP RB Gt TSTEP Input Resistance Control Range Max. Attenuation Step Resolution Attenuation Set Error Tracking Error DC Step Mute Attenuation AV = 0 to -24dB AV = -24 to -47dB AV = 0 to -24dB AV = -24 to -47dB adjacent attenuation steps from 0dB to AV max 80 20 45 45 0.5 -1.0 -1.5 33 47 47 1 0 0 0 0 0 0.5 100 50 49 49 1.5 1.0 1.5 1 2 3 K dB dB dB dB dB dB dB mV mV dB
BASS CONTROL (The center frequency and the response quality can be chosen by the ext. circuitry)
Control Range Step Resolution Internal Feedback Resistance Max. Boost/cut +12.0 1 33 +14.0 2 44 +16.0 3 55 dB dB K
TREBLE CONTROL (The center frequency and the response quality can be chosen by the ext. circuitry)
Control Range Step Resolution Max. Boost/cut +13.0 1 +14.0 2 +15.0 3 dB dB
MIDDLE CONTROL (The center frequency and the response quality can be chosen by the ext. circuitry)
Gm MSTEP RM CRANGE SSTEP EA ET VDC Amute Control Range Step Resolution Internal Feedback Resistance Max. Boost/cut +12.0 1 18.75 +14.0 2 25 +16.0 3 31.25 dB dB K
SPEAKER ATTENUATORS
Control Range Step Resolution Attenuation Set Error Tracking Error DC Step Mute Attenuation AV = 0 to -20dB AV = -20 to -56dB AV = 0 to -24dB AV = -24 to -47dB adjacent attenuation steps 80 0.5 -1.5 -2 76 1 0 0 0 0 0 100 1.5 1.5 2 1 2 3 dB dB dB dB dB dB mV dB
3/17
TDA7438
ELECTRICAL CHARACTERISTICS (continued.)
Symbol Parameter Test Condition Min. Typ. Max. Unit
AUDIO OUTPUTS
VCLIP RL RO VDC Clipping Level Output Load Resistance Output Impedance DC Voltage Level d = 0.3% 2.1 2 10 2.6 40 3.8 70 VRMS K V V dB dB dB dB dB %
GENERAL (Gain, Bass, Treble, Middle Controls Flat)
ENO Et Output Noise Total Tracking Error
(Volume + Speaker Attenuator)
All gains = 0dB; BW = 20Hz to 20KHz flat AV = 0 to -24dB AV = -24 to -47dB AV = -47 to -79dB All gains 0dB; VO = 1VRMS ; AV = 0; VI = 1VRMS ; 90 80
5 0 0 0 106 100 0.01
15 1 2 3
S/N SC d
Signal to Noise Ratio Channel Separation Left/Right Distortion
0.08
BUS INPUT
V IL VIH IIN Input Low Voltage Input High Voltage Input Current 1 VIN = 0.4V 3 -5 5 V V A
TEST CIRCUIT
5.6nF 2.2F MIN(L) 2.7K 18nF 5.6K 22nF 100nF 100nF
MUXOUTL L-IN1 0.47F L-IN2 0.47F L-IN3 0.47F 5 100K 4 100K G 3 100K 6
INL
TREBLE(L) 7 18
MOUT(L) 17 RM 16
BIN(L) 14 RB
BOUT(L) 15
VOLUME
TREBLE
MIDDLE
BASS
SPKR ATT LEFT
27
LOUT
R-IN1 0.47F R-IN2 0.47F R-IN3 0.47F
2 100K 1 100K 28 100K
0/30dB 2dB STEP
21 I CBUS DECODER + LATCHES
2
22 20
SCL SDA DIGGND
G
VOLUME
TREBLE
MIDDLE
BASS
SPKR ATT RIGHT VREF
26
ROUT
24 INPUT MULTIPLEXER + GAIN 8 MUXOUTR INR 9 TREBLE(R) 19 MIN(R) 10 RM 11 12 BIN(R) RB 13 BOUT(R) SUPPLY 25
VS AGND
23 CREF
MOUT(R)
2.2F 5.6nF
18nF 2.7K
22nF 100nF 5.6K
100nF
10F
D96AU490A
4/17
TDA7438
APPLICATION 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 TDA7438 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 = 44K typical. The Middle cell has an internal resistor Ri = 25K typical. Several filter types can be implemented, connecting external components to the Bass/Middle IN and OUT pins. Figure 1. R2 =
Ri internal IN C1 R2
D95AU313
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 factor are computed as follows: FC = 1 2 Ri, R2, C1, C2 R2 C2 + R2 C1 + Ri C1 R2 C1 + R2 C2 Ri R2 + C1 C2 R2 C1 + R2 C2
AV =
Q=
Viceversa, once Fc, Av, and Ri internal value are fixed, the external components values will be: C1 = AV - 1 2 Ri Q C2 = Q2 C1 AV - 1 Q2
AV - 1 - Q2 2 C1 FC (AV - 1) Q
OUT C2
Treble Stage The treble stage is a high pass filter whose time constant is fixed by an internal resistor (25K typical) and an external capacitor connected between treble pins and ground Typical responses are reported in Figg. 10 to 13. CREF The suggested 10F reference capacitor (CREF) value can be reduced to 4.7F if the application requires faster power ON. Figure 3: THD vs. RLOAD
Figure 2: THD vs. frequency
5/17
TDA7438
Figure 4: Channel separation vs. frequency Figure 5: Bass response
Ri = 44k C9 = C10 = 100nF (Bout, Bin) R3 = 5.6k
Figure 6: Middle response
Ri = 25k C9 = 15nF (MIN) C6 - 22nF (MOUT) R1 = 2.7k
Figure 7: Treble response
Figure 8: Typical tone response
6/17
TDA7438
I2C BUS INTERFACE Data transmission from microprocessor to the TDA7438 and vice versa takes place through the 2 wires I2C 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, the data 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 acFigure 3: Data Validity on the I2CBUS knowledge bit. The MSB is transferred first. Acknowledge The master (P) puts a resistive HIGH level on the SDA line during the acknowledge clock pulse (see fig. 5). The peripheral (audio processor) that acknowledges has to pull-down (LOW) the SDA line during this clock pulse. The audio processor which has been addressed has to generate an acknowledge after the reception of each byte, otherwise the SDA line 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. Transmission without Acknowledge Avoiding to detect the acknowledge of the audio processor, the P can use a simpler transmission: simply it waits one clock without checking the slave acknowledging, and sends the new data. This approach of course is less protected from misworking.
Figure 4: Timing Diagram of I2CBUS
Figure 5: Acknowledge on the I2CBUS
7/17
TDA7438
SOFTWARE SPECIFICATION Interface Protocol The interface protocol comprises: A start condition (S) A chip address byte, containing the TDA7438 address A subaddress bytes A sequence of data (N byte + acknowledge) A stop condition (P)
CHIP ADDRESS MSB S 1 0 0 0 1 0 0 LSB 0 ACK MSB X X
SUBADDRESS LSB X B DATA ACK MSB
DATA 1 to DATA n LSB DATA ACK P
D96AU420
ACK = Acknowledge S = Start P = Stop A = Address B = Auto Increment
EXAMPLES No Incremental Bus The TDA7438 receives a start condition, the cor-
rect chip address, a subaddress with the B = 0 (no incremental bus), N-data (all these data concern the subaddress selected), a stop condition.
CHIP ADDRESS MSB S 1 0 0 0 1 0 0 LSB 0 ACK MSB X X
SUBADDRESS LSB X 0 D3 D2 D1 D0 ACK MSB
DATA LSB DATA ACK P
D96AU421
Incremental Bus The TDA7438 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 autoincrease of the subaddress whereas
SUBADDRESS from "XXX1000" to "XXX1111" of DATA are 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.
CHIP ADDRESS MSB S 1 0 0 0 1 0 0 LSB 0 ACK MSB X X
SUBADDRESS LSB X 1 D3 D2 D1 D0 ACK MSB
DATA 1 to DATA n LSB DATA ACK P
D96AU422
8/17
TDA7438
POWER ON RESET CONDITION
INPUT SELECTION INPUT GAIN VOLUME BASS MIDDLE TREBLE SPEAKER IN2 28dB MUTE 0dB 2dB 2dB MUTE
DATA BYTES Address = 88 HEX (ADDR:OPEN). FUNCTION SELECTION: First byte (subaddress)
MSB D7 X X X X X X X X D6 X X X X X X X X D5 X X X X X X X X D4 B B B B B B B B D3 0 0 0 0 0 0 0 0 D2 0 0 0 0 1 1 1 1 D1 0 0 1 1 0 0 1 1 LSB D0 0 1 0 1 0 1 0 1 SUBADDRESS INPUT SELECT INPUT GAIN VOLUME BASS MIDDLE TREBLE SPEAKER ATTENUATE "R" SPEAKER ATTENUATE "L"
B = 1: INCREMENTAL BUS ACTIVE B = 0: NO INCREMENTAL BUS X = DON'T CARE
INPUT SELECTION
MSB D7 X X X X D6 X X X X D5 X X X X D4 X X X X D3 X X X X D2 X X X X D1 0 0 1 1 LSB D0 0 1 0 1 INPUT MULTIPLEXER IN3 NOT ALLOWED IN2 IN1
9/17
TDA7438
DATA BYTES (continued) INPUT GAIN SELECTION
MSB D7 D6 D5 D4 D3 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1
GAIN = 0 to 30dB
LSB D2 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 D1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 D0 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1
INPUT GAIN 2dB STEPS 0dB 2dB 4dB 6dB 8dB 10dB 12dB 14dB 16dB 18dB 20dB 22dB 24dB 26dB 28dB 30dB
VOLUME SELECTION
MSB D7 D6 D5 D4 D3 D2 0 0 0 0 1 1 1 1 0 0 0 0 0 0 X
VOLUME = 0 to 47dB/MUTE
LSB D1 0 0 1 1 0 0 1 1 D0 0 1 0 1 0 1 0 1
VOLUME 1dB STEPS 0dB -1dB -2dB -3dB -4dB -5dB -6dB -7dB 0dB -8dB -16dB -24dB -32dB -40dB
0 0 0 0 1 1 1
0 0 1 1 0 0 1
0 1 0 1 0 1 1 X X X
MUTE
10/17
TDA7438
DATA BYTES (continued) BASS SELECTION
MSB D7 D6 D5 D4 D3 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 D2 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 D1 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0 0 LSB D0 0 1 0 1 0 1 0 1 1 0 1 0 1 0 1 0 BASS 2dB STEPS -14dB -12dB -10dB -8dB -6dB -4dB -2dB 0dB 0dB 2dB 4dB 6dB 8dB 10dB 12dB 14dB
MIDDLE SELECTION
MSB D7 D6 D5 D4 D3 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 D2 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 D1 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0 0 LSB D0 0 1 0 1 0 1 0 1 1 0 1 0 1 0 1 0 MIDDLE 2dB STEPS -14dB -12dB -10dB -8dB -6dB -4dB -2dB 0dB 0dB 2dB 4dB 6dB 8dB 10dB 12dB 14dB
11/17
TDA7438
DATA BYTES (continued) TREBLE SELECTION
MSB D7 D6 D5 D4 D3 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 D2 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 D1 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0 0 LSB D0 0 1 0 1 0 1 0 1 1 0 1 0 1 0 1 0 TREBLE 2dB STEPS -14dB -12dB -10dB -8dB -6dB -4dB -2dB 0dB 0dB 2dB 4dB 6dB 8dB 10dB 12dB 14dB
SPEAKER ATTENUATE SELECTION
MSB D7 D6 D5 D4 D3 D2 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 0 0 0 0 1 1 1 1 0 0 1 0 0 1 1 0 0 1 1 0 0 1 0 1 0 1 0 1 0 1 0 1 1 X X X D1 0 0 1 1 0 0 1 1 LSB D0 0 1 0 1 0 1 0 1 SPEAKER ATTENUATION 1dB 0dB -1dB -2dB -3dB -4dB -5dB -6dB -7dB 0dB -8dB -16dB -24dB -32dB -40dB -48dB -56dB -64dB -72dB MUTE
SPEAKER ATTENUATION = 0 to -79dB/MUTE
12/17
TDA7438
PINS: 23 PINS: 26,27
VS
VS
VS 20K
ROUT LOUT 24
CREF 20K
20A
D96AU430
D96AU434
PINS: 1, 2, 3, 4, 5, 28
PINS: 6, 8
VS 20A
MUXOUT
VS
VS 20A
IN
100K
GND
VREF
D96AU425
D96AU491
PINS: 7, 9
PINS: 10, 11
VS 20A
VS 20A
INL INR 33K
D96AU427
25K MOUT(L) MOUT(R)
D96AU431
V REF
13/17
TDA7438
PINS: 10, 17 PINS: 12,14
VS 20A
VS 20A
25K MIN(L) MIN(R)
D96AU431
44K BIN(L) BIN(R)
D96AU428
PINS: 13,15
PINS: 18, 19
VS
VS
20A
20A TREBLE(L) TREBLE(R) 50K
44K BOUT(L) BOUT(R)
D96AU429
D96AU433
PINS: 20
PINS: 21
20A SCL
SDA
20A
D96AU423
D96AU424
14/17
TDA7438
mm MIN. a1 b b1 b2 D E e e3 F I L 4.445 3.3 15.2 2.54 33.02 14.1 0.175 0.23 1.27 37.34 16.68 0.598 0.100 1.300 0.555 TYP. 0.63 0.45 0.31 0.009 0.050 1.470 0.657 MAX. MIN. inch TYP. 0.025 0.018 0.012 MAX.
DIM.
OUTLINE AND MECHANICAL DATA
DIP28
0.130
15/17
TDA7438
mm MIN. A a1 b b1 C c1 D E e e3 F L S 7.4 0.4 17.7 10 1.27 16.51 7.6 1.27 0.291 0.016 0.1 0.35 0.23 0.5 45 (typ.) 18.1 10.65 0.697 0.394 0.050 0.65 0.299 0.050 0.713 0.419 TYP. MAX. 2.65 0.3 0.49 0.32 0.004 0.014 0.009 0.020 MIN. inch TYP. MAX. 0.104 0.012 0.019 0.013
DIM.
OUTLINE AND MECHANICAL DATA
SO28
8 (max.)
16/17
TDA7438
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 publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. The ST logo is a registered trademark of STMicroelectronics (c) 1999 STMicroelectronics - Printed in Italy - All Rights Reserved STMicroelectronics GROUP OF COMPANIES Australia - Brazil - Canada - China - France - Germany - Italy - Japan - Korea - Malaysia - Malta - Mexico - Morocco - The Netherlands Singapore - Spain - Sweden - Switzerland - Taiwan - Thailand - United Kingdom - U.S.A. http://www.st.com
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