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TDA7454
4 x 35W HIGH EFFICIENCY QUAD BRIDGE CAR RADIO AMPLIFIER
HIGH OUTPUT POWER CAPABILITY: 4 x 40W/4 MAX. 4 x 35W/4 EIAJ. 4 x 25W/4 @14.4V, 1KHz, 10% 4 x 60W/2 MAX. 2 DRIVING CAPABILITY DUAL MODE OPERATING EXTERNALLY PRESETTABLE: CONVENTIONAL CLASS AB MODE, HIGH EFFICIENCY MODE LOW EXTERNAL COMPONENTS COUNT: - NO BOOTSTRAP CAPACITORS - NO EXTERNAL COMPENSATION - INTERNALLY FIXED GAIN (26dB) CLIPPING DETECTOR ST-BY FUNCTION (CMOS COMPATIBLE) MUTE FUNCTION (CMOS COMPATIBLE) AUTOMUTE AT MINIMUM SUPPLY VOLTAGE DETECTION LOW RADIATION Protections: OUPUT SHORT CIRCUIT TO GND; TO VS; ACROSS THE LOAD 3 STEPS OVERRATING CHIP TEMPERATURE WITH THERMAL WARNING LOAD DUMP VOLTAGE FORTUITOUS OPEN GND BLOCK & APPLICATION DIAGRAM MULTIPOWER BCD TECHNOLOGY
Flexiwatt 25
LOUDSPEAKER DC CURRENT ESD DESCRIPTION The TDA7454 is a new BCD technology QUAD BRIDGE type of car radio amplifier in Flexiwatt25 packagespecially intendedfor car radio applications. Among the features, its superior efficiency performance coming from the internal exclusive structure, makes it the most suitable device to simplify the thermal management in high power sets. The dissipated output power under average listening condition is in fact reduced up to 50% when compared to the level provided by conventional class AB solutions.
6 STD/HI- EFF 0.22F IN RIGHT FRONT 16 20 7 11 8 9 ST-BY 0.22F 4 13 5 12 2 3 19 18 17 SVR 10 1 21 14 24 25 23
VCC1 VCC2 VCC RIGHT FRONT + S-GND + RIGHT REAR LEFT FRONT + TAB + LEFT REAR D94AU172C
IN RIGHT REAR MUTE
22 0.22F 15
IN LEFT FRONT 100F
0.22F IN LEFT REAR CD
January 1999
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TDA7454
ABSOLUTE MAXIMUM RATINGS
Symbol Vop VS Vpeak IO IO Ptot Tstg, Tj Operating Supply Voltage DC Supply Voltage Peak Supply Voltage (for t = 50ms) Output Peak Current (not repetitive t = 100s) Output Peak Current (repetitive f > 10Hz) Power Dissipation T case = 70C Storage and Junction Temperature Parameter Value 18 28 40 8 6 86 -55 to 150 Unit V V V A A W C
THERMAL DATA
Symbol Rth j-case Description Thermal Resistance Junction-case Max Value 1 Unit C/W
PIN CONNECTION (Top view)
25 24 23 22
CD PW GND LR OUT LRMUTE OUT LR+
20 19 18 17 16 15 14 13 12 11 10 9 8 7 6
VCC2 OUT LFPW GND LF OUT LF+ STD/HEFF IN LF IN LR S GND IN RR IN RF SVR OUT RF+ PW GND RF OUT RFVCC1 OUT RR+ ST-BY OUT RRPW GND RR TAB
D94AU173A
4 3 2 1
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TDA7454
ELECTRICAL CHARACTERISTICS (Refer to the test circuit V S = 14.4V; RL = 4; f = 1KHz; T amb = 25C, unless otherwise specified
Symbol VS Id Po Parameter Supply Voltage Range Total Quiescent Drain Current Output Power THD = 10% THD = 1% THD = 10% RL = 2; THD = 1% RL = 2; Po EIAJ Po max. THD EIAJ Output Power (*) Max. Output Power (*) Total harmonic distortion Vs = 13.7V Vs = 13.7V, RL = 2 Vs = 14.4V Vs = 14.4V, RL = 2 PO = 1W to 10W; STD MODE PO = 1W; HE MODE PO = 10W; HE MODE R L = 2; HE MODE; PO = 3W R L = 2; HE MODE; PO = 15W CT R IN GV GV EIN SVR BW A SB Vsb IN Vsb OUT Isb AM VM VM IM
IN OUT
Test Condition
Min. 8 60 23 18 40 28 32 50 38 55
Typ. 140 25 20 42 30 35 52 40 60 0.03 0.04 0.1 0.06 0.15
Max. 18 250
Unit V mA W W W W W W W W
0.3 0.3 0.5 0.3 0.5 19 27 1 150
% % % % % dB K dB dB mV dB KHz
Cross Talk Input Impedance Voltage Gain Voltage Gain Match Output Noise Voltage Supply Voltage Rejection Power Bandwidth Stand-by Attenuation Stand-by in Threshold Stand-by out Threshold Stand-by Current Consumption Mute Attenuation Mute in Thereshold Mute out Threshold Mute pin Current (Sourced) Mode Select Switch
f = 1KHz to 10KHz
45 11 25
55 15 26 100
R g = 600 f = 300Hz; Vr = 1Vrms; R g = 0 to 100; (-3dB) 45 75 90 3.5
52
100 1.5 100
dB V V A dB 1.5 V V A
80 3.5 V = 0 to VS VS max = 18V Standard BTL Mode Op. (Vpin 16 ) High Efficiency Mode (Vpin 16 ) CD off: P Omin = 10W CD on: THD = 5% -10
90
1 Open
10
0.5 5 150
V A A
CD
Clip Det. out Current (Pull up to 5V with 10K)
(*) Saturated square wave output.
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TDA7454
Figure 1: Standard Test and Application Circuit.
C8 0.1F
C9 2200F Vcc1 Vcc2 6 20 9 8 OUT RF
R1 ST-BY 10K R2 MUTE 10K C1 IN RF 0.22F IN RR C2 0.22F IN LF C3 0.22F IN LR C4 0.22F S-GND 14 13 16 (*) SW1 (*) OPEN = STANDARD BTL CLOSED=HI-EFF BTL SVR C5 100F 10 15 12 11 C7 1F C6 0.1F 22 4
7
5 2 3 OUT RR
TDA7454
17 18 19 OUT LF
21 24 23 25 1 TAB OUT LR
D95AU416
CLIP DET
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TDA7454
Figure 2: P.C.B. and components layout of fig. 1 circuit. (1.25 :1 scale) COMPONENTS & TOP COPPER LAYER
BOTTOM COPPER LAYER
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TDA7454
Figure 3: Quiescent Current vs. Supply Voltage
240 200 160 120 80 40
Vi = 0 RL = 4 Ohm
Figure 4: Output Power vs. Supply Voltage
45 40 35 30 25 20 15 10
THD= 1 % RL= 4 Ohm f= 1 KHz
Id (mA)
Po (W)
THD= 10 %
8
10
12 Vs (V)
14
16
18
5
8
9
10
11
12 13 Vs (V)
14
15
16
17
18
Figure 5: Max. Output Power vs. Supply Voltage
60 55 50 45 40 35 30 25 20 15 10 5 Po (W)
Figure 6: Output Power vs. Supply Voltage
50 45 40 35 30 25 20 15 10 5
THD = 1 %
Po (W)
RL= 4 Ohm f= 1 KHz
THD = 10 % RL = 2 Ohm f = 1 KHz
8
9
10
11
12 13 Vs (V)
14
15
16
17
18
8
9
10
11 12 Vs (V)
13
14
15
16
Figure 7: Max. Output Power vs. Supply Voltage
Po (W)
Figure 8: THD vs. Output Power
10 THD (%)
75 70 65 60 55 50 45 40 35 30 25 20 15
RL= 2 Ohm f= 1 KHz
1
RL = 4 Ohm HI-EFF MODE f = 10 KHz
0.1
f = 1 KHz
8
9
10
11 12 Vs (V)
13
14
15
16
0
0
1
Po (W)
10
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TDA7454
Figure 9: THD vs. Output Power
10 THD (%)
Figure 10: Muting Attenuation vs. Vpin 22
100 90 80 70 60 50 40 30 20 10 0 OUT ATTN
1
RL= 2 Ohm HI-EFFMODE
f = 10 KHz
Po= 4 W f= 20 to 20,000 Hz
0.1
f = 1 KHz
0
0
1
Po (W)
10
0
0.5
1
1.5
2 2.5 3 3.5 Vpin22 (V)
4
4.5
5
Figure 11: THD vs. Frequency
THD (%) 10
RL = 4 Ohm Po = 1 W HI-EFF MODE
Figure 12: Supply Voltage Rejection vs. Frequency
100 90 80 70 60
Vripple= 1 Vrms Rg= 0
SVR (dB)
1
0.1
50 40 30
0
10
100
1000 f (Hz)
10000
20
10
100 f (Hz)
1000
10000
Figure 13: Cross-Talk vs. Frequency
90 80 70 60 50 40 30 20 10 100 1000 10000
Po = 4 W RL = 4 Ohm Rg = 0 HI-E FF MODE
Figure 14: Power Dissipation and Efficiency vs. Output Power
Ptot (W) 70 65 Vs= 14.4 V 60 RL = 4 x 4 Ohm 55 f = 1 KHz 50 45 HI-EFF MODE 40 n 35 30 25 20 Ptot 15 10 5 0 0.1 1 Po (W) n (%) 70 60 50 40 30 20 10 10 0
CROSSTALK (dB)
f (Hz)
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TDA7454
OPERATING PRINCIPLE. Thanks to its unique operating principle, the TDA7454 obtains a substantial reduction of power dissipation from traditional class-AB amplifiers without being affected by the massive radiation effects and complex circuitry normally associated with class-D solutions. Its is composed of 8 amplifier blocks, making up 4 bridge-equivalent channels. Half of this structure is drafted in fig 15. These blocks continuously change their connections during every single signal event, according to the instantaneous power demand. This means that at low volumes (output power steadily lower than 2.5 W) the TDA7454 acts as a Single Ended amplifier, condition where block "C" remains disabled and the block "D" behaves like a buffer, which, by furnishing the correct DC biasing (half-Vcc) to each pair of speakers, eliminate the needs of otherwise required output-decoupling capacitors. At the same time, SW1 keeps closed. thus ensuring a common biasing point for L-R front / L-R rear speakers couples. As a result, the equivalent circuit becomes that of fig. 16. The internal switches (SW1) are high-speed, dissipation-free power MOS types, whose realization has been made possible by the ST- exclusive Bypolar-CMOS-DMOS mixed technology process (BCD). From fig. 16 it can be observed that "A" and "B" amplifiers work in phase opposition. Supposing their output have the same signal (equal shape/amplitude), the current sourced by "B" will be entirely sunk by "A", while no current will flow into "D", causing no power dissipation in the latter. "A" and "B" are practically configured as a bridge whose load is constituted by Ra + Rb (= 8 Ohm, if 4 Ohm speakers are used), with considerable advantages in terms of power dissipation. Designating "A" and "B" for the reproduction of either FRONT or REAR sections of the same channel (LEFT or RIGHT), keeping the fader in centre position (same amplitude for FRONT and REAR sections) and using the same speakers, as it happens during most of the time, will transpose this best-case dissipation condition into practical applications. To fully take advantage of the TDA7454's low-dissipation feature, it is then especially important to adopt some criteria in the channels assignment, using the schematic of fig. 1 as a reference. When the power demand increases to more than 2.5 W, all the blocks will operate as amplifiers, SW1 is opened, leading to the seemingly conventional bridge configuration of fig. 17. The efficiency enhancement is based upon the concept that the average output power during the reproduction of normal music/speech programs will stand anywhere between 10 % and 15 % of the rated power (@ THD= 10 %) that the amplifier
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can deliver. This holds true even at high volumes and frequent clipping occurrence. Applied to the TDA7454 (rated power= 25 W), this will result into an average output level of 2.5 - 3 W in sine-wave operation, region where the dissipated power is about 50 % less than that of a traditional amplifier of equivalent power class (see TDA7454 vs. CLASS-AB characteristics, fig. 18). Equally favourable is the case shown by fig. 19, when gaussian-distributed signal amplitudes, which best simulates the amplifier's real working conditions, are used. APPLICATION HINTS (ref. to the circuit of fig. 1) STAND-BY and MUTING (pins 4 & 22) Both STAND-BY and MUTING pins are CMOScompatible. The current sunk by each of them is about 1 A. For pop prevention it is essential that during TURN ON/OFF sequences the muting be preventively inserted before making stand-by transitions. But, if for any reason, either muting or stand-by are not used, they have to be connected to Vcc through a 100 Kohm (minimum) resistance. The R-C networks values in fig. 1 (R1-C6 and R2C7) are meant to be the minimum-necessary for obtaining the lowest pop levels possible. Any reductions (especially for R2-C7) will inevitably impair this parameter. SVR (pin 10) The duty of the SVR capacitor (C5) is double: assuring adequate supply-ripple rejection and controlling turn ON/OFF operations. Its indicated value (100 uF) is the minimum-recommended to correctly serve both the purposes. INPUTS (pins 11-12-13-14) The inputs are internally biased at half-Vcc level. The typical input impedance is 15 KOhm, which implies using Cin (C1-C2-C3-C4) = 220 nF for obtaining a theoretical minimum-reproducible frequency of 48 Hz (-3 dB). In any case, Cin values can be enlarged if a lower frequency bound is desired, but, at any Cin enlargement must correspond a proportional increase of Csvr (C5), to safeguard the on/off pop aspect. The following table indicates the right values to be used for Cin and Csvr, whose operating voltage can be 10 V.
LOW FREQUENCY ROLL-OFF (-3dB) 48 22 16 11 Cin (F) 0.22 0.47 0.68 1 Csvr (F) 100 220 330 470
TDA7454
Table 1: MODE SELECTION TABLE OPERATION OF THE DEVICE
1) STD/HI-EFF (pin 16 = OPEN) STANDARD QUAD BRIDGE MODE HIGH-EFF QUAD BRIDGE MODE STANDARD QUAD ST-BY MODE SINGLE-ENDED MODE
Tchip (deg)
100
2) STD/HI-EFF (pin 16 = GND) HIGH-EFF QUAD BRIDGE MODE
150
17 0
STANDARD QUAD ST-BY MODE SINGLE-ENDED MODE
Tchip (deg)
150
3) STD/HI-EFF (pin 16 connected as shown in the figure below. STANDARD QUAD BRIDGE MODE OR HIGH-EFF MODE (Theatsink dependent) HIGH-EFF QUAD BRIDGE MODE
170
STANDARD QUAD ST-BY MODE SINGLE-ENDED MODE Tchip (deg)
100
150
Vref STD/HI-EFF (pin 16)
17 0
NTC t(Theatsink)
D94AU174A
OUTPUT STAGE STABILITY The TDA7454's is intrinsically stable and will properly drive any kind of conventional car-radio speakers without the need of supplementary output compensation (e.g. Boucherot cells), thus allowing a drastic reduction of the external parts whose number, abated to the essentials, reflects that of traditional amplifiers. In this respect, perfect pin-to-pin compatibility with the entire SgsThomson's 4-BTL family (TDA738X) exists. STANDARD / HIGH-EFFICIENCY OPERATION (pin 16) The TDA7454's operating mode can be selected by changing the connection of pin 16, according to table 1. At low battery levels (<10 V), the device will automatically turn into STANDARD BRIDGE mode, independently from the status of pin 16. Condition # 3 in table 1 is particularly useful when the TDA7454's operation has to be conditioned by the temperature in other more heat-sensitive devices in the same environment. The NTC resistor is a temperature sensor, to be situated near the critical part(s), will appropriately drive pin 16 through a low-power transitor. Initially the
TDA7454 can be set to operate as a STANDARD BRIDGE, turning into HIGH EFFICIENCY mode only if overheating is recognised in the critical spot, thus reducing the overall temperature in the circuit. CLIPPING DETECTOR / DIAGNOSTIC (pin 25) The TDA7454 is equipped with a diagnostic function whose output is available at pin 25. This pin requires a pull-up resistor (10 KOhm min.) to a DC source that may range from 5 V to Vcc. The following events will be recognized and signaled out: Clipping A train of negative-going pulses will appear, each of them syncronized with every single clipping event taking place in ant of the outputs. A possible application consists of filtering / integrating the pulses and implement a routine for automatically reducing / restoring the volume using microprocessor - driven audioprocessors, to counteract the clipping sound-damagingeffects. Overheating Chip temperatures above 150 oC will be signaled out at pin 25 in the form of longer-lasting pulses, as the stepping back into the operating temperature requires some time.
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TDA7454
This constitues a substantial difference from the "clipping" situation, making the two information unmistakable. Associated to a suitable external circuitry, this "warning" signal could be used to mute some portions of the I.C. (e.g. the rear channels) or to attenuate the volume. Short Circuit Some kinds of short circuit (OUT - GND, OUTVcc), either present before the power-on or made afterwards, will cause pin 25 to remain steadily low as long as the faulty condition persists. Short-circuits across the speakers will give intermittent (pulsed) signalling, proportional to the output voltage amplitude. External Layout Grounding The 4 bridge stuctures have independent power ground accesses (pins 2,8,18,24), while the signal ground is common to all of them (pin 13). The Figure 15: TDA7454's Half Structure TAB (pin 1) is connected to the chip substrate and has to be grounded to the best-filtered ground spot (usually nearby the minus terminal of the Vcc-filtering electrolytic capacitor). This same point should be used as the centre of a multi-track star-like configuration, or, alternatively, as the origin of only two separate tracks, one for P-GND, one for S-GND, each of them routed to their specific ground pin(s). This will provide the right degree of separation between P-GND and S-GND yet assuring the (necessary) electrical connection between them. The correct ground assignment for the each element of the circuit will then be: POWER GND: Battery (-), Supply filters (C8, C9), TAB (pin 1). SIGNAL GND: Pre-amplifier (Audiprocessor) ground, SVR capacitor (C5), muting/st-by capacitors (C6, C7). Figure 16: Single Ended Operation (Po < 2.5W)
A
+ RF RR
-
B
INF
INR
A
+ RF RR
-
B
INR
INF SW1 C + D
Vf
Vr
Ron2
R-channel
F-channel CONTROL LOGIC
D97AU793
if
+
if-ir
D
D97AU792
Figure 17: He Bridge Operation (Po < 2.5W)
INF
A
+ RF Vf RR
-
B
INR
Vr
C
-
+
D
D97AU794
10/13
TDA7454
Figure 18: Power Dissipation (Sine-Wave)
Pdiss (W) 55 50 45 Vs = 14.4 V RL = 4 x 4 Ohm 40 CLASS-AB 35 30 25 20 15 10 TDA7454 5 0 0.1 1 Po each channel (W)
Figure 19: Power Dissipation (Gaussian Signals)
45 40 35 30 25 20 15 10 5 0
TDA7454
Pdiss (W)
Vs = 14.4 V RL = 4 x 4 Ohm
CLASS-AB
10
0.1
1
Pout each channel (W)
10
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TDA7454
DIM. A B C D E F G G1 H H1 H2 H3 L L1 L2 L3 M M1 N O R R4 V2 V3 mm TYP. 1.90 1.40 0.90 0.39 1.00 24.00 29.23 17.00 12.80 0.80 21.97 18.97 15.70 7.85 4.00 4.00 2.20 2 1.70 0.50 inch TYP. 0.074 0.055 0.035 0.015 0.040 0.945 1.150 0.669 0.503 0.031 0.865 0.786 0.618 0.309 0.157 0.157 0.086 0.079 0.067 0.019
MIN. 4.45 1.80 0.75 0.37 0.80 23.75 28.90
MAX. 4.65 2.00 1.05 0.42 0.57 1.20 24.25 29.30
MIN. 0.175 0.070 0.029 0.014 0.031 0.935 1.138
MAX. 0.183 0.079 0.041 0.016 0.022 0.047 0.955 1.153
OUTLINE AND MECHANICAL DATA
21.57 18.57 15.50 7.70 3.70 3.60
22.37 19.37 15.90 7.95 4.30 4.40
0.849 0.731 0.610 0.303 0.145 0.142
0.880 0.762 0.626 0.313 0.169 0.173
20 45
Flexiwatt25
V3 H3
O
H H1 H2 R3 R4 A
L2
N
R
L3
L
L1
V2 D M E G G1 F B M1
C
FLEX25
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TDA7454
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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