– Output DC and AC short circuit to ground
– Overrating chip temperature
– Load dump voltage surge
– Fortuitous open ground
– Very inductive loads
■ Loudspeaker protection during short circuit for
one wire to ground
Description
The TDA2005 is a class B dual audio power
amplifier in Multiwatt11 package specifically
designed for car radio applications.
Table 1.Device summary
TDA2005
Multiwatt11
Power booster amplifiers can be easily designed
using this device that provides a high current
capability (up to 3.5 A) and can drive very low
impedance loads (down to 1.6 Ω in stereo
applications) obtaining an output power of more
than 20 W (bridge configuration).
Figure 13.Output power vs. supply voltage, R
Figure 14.Output power vs. supply voltage, R
Figure 15.Distortion vs. frequency, R
Figure 16.Distortion vs. frequency, R
Figure 19.Supply voltage rejection vs. C2 and C3, G
Figure 20.Supply voltage rejection vs. C2 and C3, G
Figure 21.Gain vs. input sensitivity R
Figure 22.Gain vs. input sensitivity R
Figure 23.Total power dissipation and efficiency vs. output power (bridge) . . . . . . . . . . . . . . . . . . . . 14
Figure 24.Total power dissipation and efficiency vs. output power (stereo) . . . . . . . . . . . . . . . . . . . . 14
Output voltage with one side of
the speaker shorted to ground
f = 100 Hz; V
= 10 kΩ; RL = 4 Ω
R
g
f = 1 kHz; V
= 4 Ω; P
R
L
= 14.4 V; RL = 4 Ω
V
S
VS = 13.2 V; RL = 3.2 Ω
Figure 5.Output offset voltage vs. supply
voltage
V
os
(mV)
100
80
= 13.2 V;
S
= 0.5 V;
ripple
= 14.4V;
S
= 13 W
tot
Figure 6.Distortion vs. output power (RL=
4 Ω)
d
(%)
10
-6060-
-58-
3036-dB
-145-°C
--2V
Vs = 14.4 V
Gv = 50 dB
R
= 4 Ω
L
f = 1 kHz
%
60
40
20
0
8
10
12
1416
Vs (V)
Figure 7.Distortion vs. output power (RL=
3.2 Ω)
d
(%)
Vs = 13.2 V
Gv = 50 dB
R
= 3.2 Ω
L
10
1
0.1
f = 1 kHz
110
Po (W)
1
0.1
110
Po (W)
8/25Doc ID 1451 Rev 4
TDA2005Electrical specifications
2.3.2 Bridge amplifier design
The following considerations can be useful when designing a bridge amplifier.
Table 5.Bridge amplifier design
ParameterSingle endedBridge
1
V
o max
I
o max
Peak output voltage (before clipping)
Peak Output current (before clipping)
-- -
2V
–()Vs2V
V
s
2
V
1
-----------------------------------
-- -
2
CEsat
2V
–
s
CEsat
R
L
–
CEsat
Vs2V
–
R
CEsat
L
-----------------------------------
P
o max
RMS output power (before clipping)
V
2V
–()
1
s
-- -
-------------------------------------------
4
2R
2
CEsat
L
V
2V
–()
s
-------------------------------------------
2R
2
CEsat
L
Where:
V
V
R
= output transistors saturation voltage
CE sat
= allowable supply voltage
S
= load impedance
L
Voltage and current swings are twice for a bridge amplifier in comparison with single ended
amplifier.
In order words, with the same R
the bridge configuration can deliver an output power that is
L
four times the output power of a single ended amplifier, while, with the same max output
current the bridge configuration can deliver an output power that is four times the output
power of a single ended amplifier, while, with the same max output current the bridge
configuration can deliver an output power that is twice the output power of a single ended
amplifier.
Core must be taken when selecting V
and RL in order to avoid an output peak current
S
above the absolute maximum rating.
From the expression for I
, assuming VS = 14.4V and V
Omax
= 2V, the minimum load
CE sat
that can be driven by TDA2005 in bridge configuration is:
R
Lmin
–
I
Omax
CEsat
----------------------------------- -
14.4 4–
-------------------- -2.97Ω===
3.5
Vs2V
The voltage gain of the bridge configuration is given by (see Figure 36):
V
v
0
------ -1
V
1
G
Doc ID 1451 Rev 49/25
R
1
--------------------------
R2R4⋅
⎛⎞
-------------------- -
⎜⎟
R
+
⎝⎠
2R4
R
3
------ -++==
R
4
Electrical specificationsTDA2005
For sufficiently high gains (40 to 50 dB) it is possible to put R2 = R4 and R3 = 2R1,
simplifying the formula in:
The recommended values of the components are those shown on bridge application circuit
of Figure 3. Different values can be used; the following table can help the designer.
Table 8.Recommended values of the component of the bridge application circuit
Component
Recommended
value
PurposeLarger than Smaller than r
C12.2 μFInput DC decoupling--
High Turn on Pop, Higher
low frequency cutoff
Increase of Noise
C22.2 μF
Optimization of turn on
Pop and turn on Delay
High turn on delay
C30.1 μFSupply bypass-Danger of oscillation
Increase of SVR,
C410 μFRipple rejection
Increase of the Switch-
Degradation of SVR
on Time
C5, C7100 μFBootstrapping-
Feedback input DC
C6, C8220 μF
decoupling, low
frequency cut-off
-
Increase of distortion at
low frequency
Danger of oscillation at
high frequencies with
inductive loads
C9, C100.1 μFFrequency stability-Danger of oscillation
R1120 kΩ
Optimization of the
output symmetry
Smaller P
omax
Smaller P
omax
R21 kΩ---
R32 kΩ---
Closed loop gain setting
R4, R512 Ω
(see Bridge Amplifier
(1)
Design
)
--
R6, R71 ΩFrequency stability
1. The closed loop gain must be higher than 32 dB.
Danger of oscillation at
high frequencies with
-
inductive loads
Doc ID 1451 Rev 415/25
Application informationTDA2005
4 Application information
Figure 25. Bridge amplifier without boostrap
Figure 26. PC board and components layout of Figure 25
16/25Doc ID 1451 Rev 4
TDA2005Application information
Figure 27. Low cost bridge amplifier (GV = 42dB)
Figure 28. PC board and components layout of Figure 27
Doc ID 1451 Rev 417/25
Application informationTDA2005
Figure 29. 10 + 10 W stereo amplifier with tone balance and loudness control
Figure 30. Tone control response (circuit of Figure 29)
The TDA2005 has a circuit which enables it to withstand voltage pulse train, on Pin 9, of the
type shown in Figure 36. If the supply voltage peaks to more than 40 V, then an LC filter
must be inserted between the supply and pin 9, in order to assure that the pulses at pin 9
will be held within the limits shown.
A suggested LC network is shown in Figure 35. With this network, a train of pulses with
amplitude up to 120 V and width of 2 ms can be applied at point A. This type of protection is
ON when the supply voltage (pulse or DC) exceeds 18 V. For this reason the maximum
operating supply voltage is 18 V.
20/25Doc ID 1451 Rev 4
TDA2005Application information
Figure 35. Suggested LC network circuit
Figure 36. Voltage gain bridge configuration
4.1.2 Short circuit (AC and DC conditions)
The TDA2005 can withstand a permanent short-circuit on the output for a supply voltage up
to 16 V.
4.1.3 Polarity inversion
High current (up to 10 A) can be handled by the device with no damage for a longer period
than the blow-out time of a quick 2 A fuse (normally connected in series with the supply).
This feature is added to avoid destruction, if during fitting to the car, a mistake on the
connection of the supply is made.
4.1.4 Open ground
When the ratio is in the ON condition and the ground is accidentally opened, a standard
audio amplifier will be damaged. On the TDA2005 protection diodes are included to avoid
any damage.
4.1.5 Inductive load
A protection diode is provided to allow use of the TDA2005 with inductive loads.
4.1.6 DC voltage
The maximum operating DC voltage for the TDA2005 is 18 V. However the device can
withstand a DC voltage up to 28 V with no damage. This could occur during winter if two
batteries are series connected to crank the engine.
Doc ID 1451 Rev 421/25
Application informationTDA2005
4.1.7 Thermal shut-down
The presence of a thermal limiting circuit offers the following advantages:
1.an overload on the output (even if it is permanent), or an excessive ambient
temperature can be easily withstood.
2. the heatsink can have a smaller factor of safety compared with that of a conventional
circuit. There is no device damage in the case of excessive junction temperature : all
that happens is that P
(and therefore P
o
) and Id are reduced.
tot
The maximum allowable power dissipation depends upon the size of the external heatsink
(i.e. its thermal resistance); Figure 37 shows the power dissipation as a function of ambient
temperature for different thermal resistance.
4.1.8 Loudspeaker protection
The circuit offers loudspeaker protection during short circuit for one wire to ground.
Figure 37. Maximum allowable power dissipa-
tion vs. ambient temperature
P
(W)
20
16
12
8
tot
32
28
24
R
4
0
-50
th
= 8˚C/W
0
R
th
= 4˚C/W
R
th
= 2˚C/W
50
INFINITE HEATSINK
100 T
amb
(˚C)
Figure 39. Output power and drain current vs.
case temperature (R
P
o
(W)
8
P
o
6
I
d
= 3.2 Ω)
L
VS = 13.2V
Ω
= 3.2
R
L
f = 1 kHz
1.2
0.9
I
(A)
d
Figure 38. Output power and drain current vs.
case temperature (R
P
o
(W)
16
12
8
4
04080120160
I
d
P
o
= 4 Ω)
L
VS = 14.4V
Ω
= 4
R
L
f = 1 kHz
I
d
(A)
1.2
0.9
0.6
0.3
(˚C)
T
case
4
2
04080120160
0.6
0.3
T
(˚C)
case
22/25Doc ID 1451 Rev 4
TDA2005Package information
5 Package information
In order to meet environmental requirements, ST offers these devices in different grades of
ECOPACK
®
packages, depending on their level of environmental compliance. ECOPACK
®
specifications, grade definitions and product status are available at: www.st.com.
ECOPACK
®
is an ST trademark.
Figure 40. Multiwatt11 mechanical data and package dimensions
DIM.
A50.197
B2.650.104
C1.60.063
D10.039
E0.490.55 0.0190.022
F0.880.95 0.0350.037
G1.451.71.95 0.057 0.067 0.077
G116.751717.25 0.659 0.669 0.679
H119.60.772
H220.20.795
L21.922.2 22.5 0.862 0.874 0.886
L121.722.122.5 0.854 0.87 0.886
L217.418.1 0.6850.713
L317.25 17 .5 17.75 0.679 0.689 0.699
L410.310.710.9 0.406 0.421 0.429
L72.652.90.1040.114
M4.25 4.5 54.85 0.167 0.179 0.191
M14.73 5.085.43 0.186 0.200 0.214
S1.92.60.0750.102
S11.92.60.0750.102
Dia1 3.653.85 0.1440.152
mminch
MIN. TYP. MAX. MIN. TYP. MAX.
OUTLINE AND
MECHANICAL DATA
Multiwatt11 (Vertical)
0016035 H
Doc ID 1451 Rev 423/25
Revision historyTDA2005
6 Revision history
Table 9.Document revision history
DateRevisionChanges
09-Jun-19981Initial release.
20-May-20002Update logo.
10-Sep-20033Update package drawing.
Document reformatted.
28-Jan-20104
Updated Features, Description and Table 1: Device summary in
cover page.
24/25Doc ID 1451 Rev 4
TDA2005
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