STMICROELECTRONICS TDA-7296

TDA7296
70V - 60W DMOS AUDIO AMPLIFIER WITH MUTE/ST-BY
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FEATURES
Figure 1. Package
MULTIPOWER BCD TECHNOLOGY
VERY HIGH OPERATING VOLTAGE RANGE
(±35V)
DMOS POWER STAGE
HIGH OUTPUT POWER (UP TO 60W MUSIC
POWER)
MUTING/STAND-BY FUNCTIONS
NO SWITCH ON/OFF NOISE
NO BOUCHEROT CELLS
VERY LOW DISTORTION
VERY LOW NOISE
SHORT CIRCUIT PROTECTION
THERMAL SHUTDOWN
Multiwatt15V
Multiwatt15H
(Short Leads)
Table 1. Order Codes
Part Number
Package
TDA7296
Multiwatt15V
TDA7296HS
Multiwatt15H (Short Leads)
Thanks to the wide voltage range and to the high
out current capability it is able to supply the highest power into both 4Ω and 8Ω loads even in presence of poor supply regulation, with high Supply
Voltage Rejection.
DESCRIPTION
The built in muting function with turn on delay simplifies the remote operation avoiding switching onoff noises.
The TDA7296 is a monolithic integrated circuit in
Multiwatt15 package, intended for use as audio
class AB amplifier in Hi-Fi field applications (Home
Stereo, self powered loudspeakers, Topclass TV).
Figure 2. Typical Application and Test Circuit
C7 100nF
+Vs
C6 1000µF
R3 22K
C2
22µF
R2
680Ω
IN-
2
IN+
3
IN+MUTE
4
C1 470nF
+Vs
+PWVs
7
13
-
14
C5
22µF
+
R1 22K
VM
R5 10K
VSTBY
MUTE
10
STBY
9
R4 22K
C3 10µF
C4 10µF
OUT
6
MUTE
THERMAL
SHUTDOWN
STBY
BOOTSTRAP
S/C
PROTECTION
1
8
15
STBY-GND
-Vs
-PWVs
C9 100nF
R6
2.7Ω
C10
100nF
C8 1000µF
D93AU011
-Vs
Note: The Boucherot cell R6, C10, normally not necessary for a stable operation it could
be needed in presence of particular load impedances at VS <±25V.
February 2005
Rev. 10
1/15
TDA7296
Figure 3. Pin Connection
Table 2. Absolute Maximum Ratings
Symbol
Parameter
Value
Unit
±35
V
VS
Supply Voltage (No Signal)
IO
Output Peak Current
5
A
Ptot
Power Dissipation Tcase = 70°C
50
W
Top
Operating Ambient Temperature Range
0 to 70
°C
150
°C
Tstg, Tj
Storage and Junction Temperature
Table 3. Thermal Data
Symbol
Rth j-case
Parameter
Thermal Resistance Junction-case
Figure 4. Block Diagram
2/15
Typ.
Max
Unit
1
1.5
°C/W
TDA7296
Table 4. Electrical Characteristcs (Refer to the Test Circuit VS = ±24V, RL = 8Ω, GV = 30dB; Rg = 50Ω;
Tamb = 25°C, f = 1 kHz; unless otherwise specified).
Symbol
Parameter
Test Condition
Min.
VS
Supply Range
±10
Iq
Quiescent Current
20
I
Input Bias Current
b
Typ.
30
Max.
Unit
±35
V
65
mA
500
nA
VOS
Input Offset Voltage
-10
10
mV
IOS
Input Offset Current
-100
100
nA
PO
RMS Continuous Output
Power
d = 05%
VS = ± 24V, RL = 8Ω;
VS = ± 21V, RL = 6Ω;
VS = ± 18V, RL = 4Ω;
Music Power (RMS)
∆t = 1s (*)
d = 10%
VS = ± 29V, RL = 8Ω;
VS = ± 24V, RL = 6Ω;
VS = ± 22V, RL = 4Ω;
Total Harmonic Distortion (**)
PO = 5W; f = 1kHz
PO = 0.1 to 20W; f = 20Hz to 20kHz
d
27
27
27
Slew Rate
GV
Open Loop Voltage Gain
GV
Closed Loop Voltage Gain (1)
eN
Total Input Noise
Ri
SVR
TS
frequency response (-3dB)
W
W
W
%
0.01
0.1
7
10
24
30
A = curve
dB
40
2
5
µV
20Hz to 20kHz
100
f = 100Hz; Vripple = 0.5Vrms
dB
µV
1
PO =1W
%
%
V/µs
80
Input Resistance
Supply Voltage Rejection
60
60
60
0.1
f = 20Hz to 20kHz
fL ,fH
W
W
W
0.005
VS = ± 18V, RL = 4Ω;
PO = 5W; f = 1kHz
PO = 0.1 to 20W; f = 20Hz to 20kHz
SR
30
30
30
60
Thermal Shutdown
kΩ
75
dB
145
°C
STAND-BY FUNCTION (Ref: -Vs or GND)
VST on
Stand-by on Threshold
VST off
Stand-by off Threshold
3.5
Stand-by Attenuation
70
ATTst-by
Iq st-by
1.5
Quiescent Current @ Stand-by
V
V
90
1
dB
3
mA
1.5
V
MUTE FUNCTION (Ref: -Vs ro GND)
VMon
Mute on Threshold
VMoff
Mute off Threshold
3.5
Mute AttenuatIon
60
ATTmute
V
80
dB
Note (*):
MUSIC POWER is the maximal power which the amplifier is capable of producing across the rated load resistance (regardless of non linearity)
1 sec after the application of a sinusoidal input signal of frequency 1KHz.
Note (**): Tested with optimized Application Board (see fig.5)
3/15
TDA7296
Figure 5. P.C.B. and Components Layout of the Circuit of figure 2.
Note:
The Stand-by and Mute functions can be referred either to GND or -VS.
On the P.C.B. is possible to set both the configuration through the jumper J1.
4/15
TDA7296
3
APPLICATION SUGGESTIONS
(see Test and Application Circuits of the Fig. 2)
The recommended values of the external components are those shown on the application circuit of Figure
2. Different values can be used; the following table can help the designer.
COMPONENTS
SUGGESTED
VALUE
PURPOSE
R1 (*)
22k
R2
680Ω
R3 (*)
22k
R4
22k
R5
LARGER THAN
SUGGESTED
SMALLER THAN
SUGGESTED
Input Resistance
Increase Input
Impedance
Decrease Input
Impedance
Closed Loop Gain
Set to 30db (**)
Decrease of Gain
Increase of Gain
Increase of Gain
Decrease of Gain
St-by Time Constant
Larger St-by
ON/OFF Time
Smaller St-by ON/OFF
Time; Pop Noise
10k
Mute Time Constant
Larger Mute
ON/OFF Time
Smaller Mute
ON/OFF Time
C1
0.47µF
Input DC Decoupling
Higher Low Frequency
Cutoff
C2
22µF
Feedback DC
Decoupling
Higher Low Frequency
Cutoff
C3
10µF
Mute Time Constant
Larger Mute
ON/OFF Time
Smaller Mute ON/OFF
Time
C4
10µF
St-by Time Constant
Larger St-by
ON/OFF Time
Smaller St-by ON/OFF
Time; Pop Noise
C5
22µF
Bootstrapping
Signal Degradation at
Low Frequency
C6, C8
1000µF
Supply Voltage Bypass
Danger of Oscillation
C7, C9
0.1µF
Supply Voltage Bypass
Danger of Oscillation
(*) R1 = R3 for pop optimization
(**) Closed Loop Gain has to be ≥ 24dB
5/15
TDA7296
4
TYPICAL CHARACTERISTICS
(Application Circuit of fig 2 unless otherwise specified)
Figure 6. : Output Power vs. Supply Voltage.
Figure 9. Distortion vs. Output Power
Figure 7. Distortion vs. Output Power
Figure 10. Distortion vs. Frequency
Figure 8. Output Power vs. Supply Voltage
Figure 11. Distortion vs. Frequency
6/15
TDA7296
Figure 12. Quiescent Current vs. Supply
Voltage
Figure 15. St-by Attenuation vs. Vpin9
Figure 13. Supply Voltage Rejection vs.
Frequency
Figure 16. Power Dissipation vs. Output Power
Figure 14. Mute Attenuation vs. Vpin10
Figure 17. Power Dissipation vs. Output Power
7/15
TDA7296
5
INTRODUCTION
In consumer electronics, an increasing demand has arisen for very high power monolithic audio amplifiers
able to match, with a low cost the performance obtained from the best discrete designs.
The task of realizing this linear integrated circuit in conventional bipolar technology is made extremely difficult by the occurence of 2nd breakdown phenomenon. It limits the safe operating area (SOA) of the power devices, and as a consequence, the maximum attainable output power, especially in presence of highly
reactive loads. Moreover, full exploitation of the SOA translates into a substantial increase in circuit and
layout complexity due to the need for sophisticated protection circuits.
To overcome these substantial drawbacks, the use of power MOS devices, which are immune from secondary breakdown is highly desirable. The device described has therefore been developed in a mixed bipolar-MOS high voltage technology called BCD 80.
5.1 Output Stage
The main design task one is confronted with while developing an integrated circuit as a power operational
amplifier, independently of the technology used, is that of realising the output stage. The solution shown
as a principle schematic by Fig 18 represents the DMOS unity-gain output buffer of the TDA7296.
This large-signal, high-power buffer must be capable of handling extremely high current and voltage levels
while maintaining acceptably low harmonic distortion and good behaviour over frequency response; moreover, an accurate control of quiescent current is required.
A local linearizing feedback, provided by differential amplifier A, is used to fullfil the above requirements,
allowing a simple and effective quiescent current setting. Proper biasing of the power output transistors
alone is however not enough to guarantee the absence of crossover distortion. While a linearization of the
DC transfer characteristic of the stage is obtained, the dynamic behaviour of the system must be taken
into account.
A significant aid in keeping the distortion contributed by the final stage as low as possible is provided by
the compensation scheme, which exploits the direct connection of the Miller capacitor at the amplifier’s
output to introduce a local AC feedback path enclosing the output stage itself.
5.2 Protections
In designing a power IC, particular attention must be reserved to the circuits devoted to protection of the
device from short circuit or overload conditions.
Due to the absence of the 2nd breakdown phenomenon, the SOA of the power DMOS transistors is delimited only by a maximum dissipation curve dependent on the duration of the applied stimulus.
In order to fully exploit the capabilities of the power transistors, the protection scheme implemented in this
device combines a conventional SOA protection circuit with a novel local temperature sensing technique
which " dynamically" controls the maximum dissipation.
Figure 18. Principle Schematic of a DMOS Unity-gain Buffer.
8/15
TDA7296
Figure 19. Turn ON/OFF Suggested Sequence
+Vs
(V)
+35
-35
-Vs
VIN
(mV)
VST-BY
PIN #9
(V)
VMUTE
PIN #10
(V)
5V
5V
IP
(mA)
VOUT
(V)
OFF
ST-BY
PLAY
MUTE
ST-BY
OFF
MUTE
D93AU013
In addition to the overload protection described above, the device features a thermal shutdown circuit
which initially puts the device into a muting state (@ Tj = 145°C) and then into stand-by (@ Tj = 150°C).
Full protection against electrostatic discharges on every pin is included.
5.3 Other Features
The device is provided with both stand-by and mute functions, independently driven by two CMOS logic
compatible input pins.
The circuits dedicated to the switching on and off of the amplifier have been carefully optimized to avoid
any kind of uncontrolled audible transient at the output.
The sequence that we recommend during the ON/OFF transients is shown by Figure 19.
The application of figure 20 shows the possibility of using only one command for both st-by and mute functions. On both the pins, the maximum applicable range corresponds to the operating supply voltage.
9/15
TDA7296
Figure 20. Single Signal ST-BY/MUTE Control Circuit
MUTE
MUTE/
ST-BY
STBY
20K
10K
30K
10µF
1N4148
10µF
D93AU014
6
BRIDGE APPLICATION
Another application suggestion is the BRIDGE configuration, where two TDA7296 are used, as shown by
the schematic diagram.
In this application, the value of the load must not be lower than 8 Ohm for dissipation and current capability
reasons. A suitable field of application includes HI-FI/TV subwoofers realizations. The main advantages
offered by this solution are:
– High power performances with limited supply voltage level.
– Considerably high output power even with high load values (i.e. 16 Ohm).
The characteristics shown by figures 23 and 24, measured with loads respectively 8 Ohm and 16 Ohm.
With Rl= 8 Ohm, Vs = ±18V the maximum output power obtainable is 60W, while with Rl=16 Ohm, Vs =
±24V the maximum Pout is 60W.
Figure 21. Bridge Application Circuit
+Vs
0.22µF
2200µF
7
3
Vi
0.56µF
13
6
14
+
22µF
-
22K
22K
2
1
4
ST-BY/MUTE
10
680
9
15
8
20K
22K
22µF
10
10K
30K
9
15
8
22µF
6
3
0.56µF
-Vs
0.22µF
2200µF
1N4148
14
+
22K
2
1
4
7
13
22µF
22K
680
D93AU015A
10/15
TDA7296
Figure 22. Frequency Response of the Bridge
Application
Figure 24. Distortion vs. Output Power
Figure 23. Distortion vs. Output Power
11/15
TDA7296
Figure 25. Multiwatt15V Mechanical Data & Package Dimensions
DIM.
mm
MIN.
TYP.
inch
MAX.
MIN.
TYP.
A5
MAX.
0.197
B
2.65
C
0.104
1.6
D
OUTLINE AND
MECHANICAL DATA
0.063
1
0.039
E
0.49
0.55
0.019
0.022
F
0.66
0.75
0.026
0.030
G
1.02
1.27
1.52
0.040
0.050
0.060
G1
17.53
17.78
18.03
0.690
0.700
0.710
H1
19.6
0.772
H2
20.2
0.795
L
21.9
22.2
22.5
0.862
0.874
0.886
L1
21.7
22.1
22.5
0.854
0.87
0.886
L2
17.65
18.1
0.695
L3
17.25
17.5
17.75
0.679
0.689
L4
10.3
10.7
10.9
0.406
0.421
L7
2.65
2.9
0.104
M
4.25
4.55
4.85
0.167
0.179
M1
4.73
5.08
5.43
0.186
0.200
S
1.9
2.6
0.075
0.102
S1
1.9
2.6
0.075
0.102
Dia1
3.65
3.85
0.144
0.152
0.713
0.699
0.429
0.114
0.191
0.214
Multiwatt15 (Vertical)
0016036 J
12/15
TDA7296
Figure 26. Multiwatt15 Horizontal (Short leads) Mechanical Data & Package Dimensions
mm
inch
DIM.
MIN.
TYP.
MAX.
MIN.
TYP.
A
5
0.197
B
2.65
0.104
C
1.6
0.063
E
0.49
0.55
0.019
0.022
F
0.66
0.75
0.026
0.030
G
1.02
1.27
1.52
0.040
0.050
0.060
G1
17.53
17.78
18.03
0.690
0.700
0.709
H1
19.6
20.2
0.772
0.795
H2
19.6
20.2
0.772
0.795
L1
17.80
18.00
18.20
0.701
0.709
L3
17.25
17.5
17.75
0.679
0.689
0.699
L4
10.3
10.7
10.9
0.406
0.421
0.429
L5
2.70
3.00
3.30
0.106
0.118
0.130
L7
2.65
2.9
0.104
L2
2.54
R
OUTLINE AND
MECHANICAL DATA
MAX.
0.717
0.100
1.5
0.114
0.059
S
1.9
2.6
0.075
0.102
S1
1.9
2.6
0.075
0.102
Dia1
3.65
3.85
0.144
0.152
V
Multiwatt15 H (Short leads)
V
V
V
R
R
A
B
C
V
L5
E
L2
L1
H2
L3
L4
L7
N
F
H2
H1
G1
Diam 1
G
S
MW15HME
R1
P
S1
0067558 E
13/15
TDA7296
Table 5. Revision History
Date
Revision
January 2004
8
First Issue in EDOCS DMS
September 2004
9
Added Package Multiwatt15 Horizontal (Short leads)
February 2005
10
Corrected mistyping error in Table 2.
14/15
Description of Changes
TDA7296
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. Specifications 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.
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All other names are the property of their respective owners
© 2005 STMicroelectronics - All rights reserved
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