August 2011 Doc ID 1461 Rev 3 1/18
18
TDA2050
32 W hi-fi audio power amplifier
Features
■High output power
(50 W music power IEC 268.3 rules)
■High operating supply voltage (50 V)
■Single or split supply operations
■Very low distortion
■Short-circuit protection (OUT to GND)
■Thermal shutdown
Description
The TDA 2050 is a monolithic integrated circuit in
a Pentawatt package, intended for use as an
audio class-AB audio amplifier.
Thanks to its high power capability the TDA2050
is able to provide up to 35 W true RMS power into
a 4 ohm load at THD = 0%, VS = ±18 V, f = 1 kHz
and up to 32 W into an 8 ohm load at THD = 10%,
VS = ±22 V, f = 1 kHz.
Moreover, the TDA2050 delivers typically 50 W
music power into a 4 ohm load over 1 sec at
VS = 22.5 V, f = 1 kHz.
The high power and very low harmonic and
crossover distortion (THD = 0.05% typ, at
VS = ±22 V, PO = 0.1 to 15 W, RL= 8 ohm,
f = 100 Hz to 15 kHz) make the device most
suitable for both hi-fi and high-end TV sets.
Figure 1. Test and application circuit
Table 1. Device summary
Order code Package
TDA2050V Pentawatt vertical
Pentawatt V
www.st.com
Device overview TDA2050
2/18 Doc ID 1461 Rev 3
1 Device overview
Table 2. Absolute maximum ratings
Table 3. Thermal data
Figure 2. Pin connections (top view)
Figure 3. Schematic diagram
Symbol Parameter Value Unit
VsSupply voltage ±25 V
ViInput voltage Vs
ViDifferential input voltage ±15 V
IoOutput peak current (internally limited) 5 A
Ptot Power dissipation at TCASE = 75 °C 25 W
Tstg, TjStorage and junction temperature -40 to 150 °C
Symbol Parameter Value Unit
Rth j-case Thermal resistance junction-case 3 (max) °C
TDA2050 Device overview
Doc ID 1461 Rev 3 3/18
The values given in the following table refer to the test circuit VS = ±18 V, Tamb = 25 °C,
f = 1 kHz, unless otherwise specified.
Table 4. Electrical characteristics
Symbol Parameter Test conditions Min. Typ. Max. Unit
Vs Supply voltage range ± 4.5 ± 25 V
IdQuiescent drain current Vs = ± 4.5
Vs = ± 25
30
55
50
90
mA
mA
IbInput bias current Vs = ± 22 0.1 0.5 µA
VOS Input offset voltage Vs = ± 22 ± 15 mV
IOS Input offset current ± 200 nA
Po
Output power
d = 0.5%,
RL = 4 Ω
RL = 8 Ω
Vs = ± 22 V, RL = 8 Ω
24
22
28
18
25
W
W
W
d = 10%,
RL = 4 Ω
RL = 8 Ω
Vs = ± 22 V, RL = 8 Ω
35
22
32
W
W
W
Music power IEC268.3 rules d = 10%, T = 1s
RL = 4 Ω; Vs = ± 22.5 V 50 W
d Distortion
Po = 0.1 to 24W, RL = 4 Ω, f = 1 kHz
f = 100 to 10 kHz, Po = 0.1 to 18 W 0.03 0.5
0.5
%
%
Vs = ± 22 V, RL = 8 Ω,
f = 1 kHz, Po = 0.1 to 20 W,
f = 100 Hz to 10 kHz;
Po = 0.1 to 15 W
0.02
0.5
%
%
SR Slew rate 5 8 V/µs
Gv Voltage gain (open loop) f = 1 kHz 80 dB
Gv Voltage gain (closed loop) f = 1 kHz 30 30.5 31 dB
BW Power bandwidth (-3dB) Vi = 200 mW, RL = 4 Ω; 20 to 80.000 Hz
eNInput noise voltage B = Curve A
B = 22 Hz to 22 kHz
4
510
µV
µV
RiInput resistance (pin 1) 500 kΩ
SVR Supply voltage rejection Rg = 22 kΩ, f = 100 Hz;
Vripple = 0.5 VRMS
45 dB
h Efficiency Po = 28 W, RL = 4 Ω65 %
Po = 25 W, RL = 8 Ω,Vs = ± 22 V, 67 %
Tsd-j
Thermal shutdown junction
temperature 150 °C
Device overview TDA2050
4/18 Doc ID 1461 Rev 3
Figure 4. Split-supply typical application circuit
Figure 5. PC board and component layout of split-supply typical application circuit
R3
R2
R1
C2
C4
C3
R4
C5
C6
C1
C7
+Vs
R
L
-Vs
TDA2050
Vi
TDA2050 Split-supply application suggestions
Doc ID 1461 Rev 3 5/18
2 Split-supply application suggestions
The recommended values of the external components are those shown on the application
circuit of Figure 5. Different values can be used. The following table can help the designer.
Table 5. Recommended values of external components
Component Recommended
value Purpose Larger than
recommended value
Smaller than
recommended value
R1 22 kΩInput impedance Increase of input
impedance
Decrease of Input
Impedance
R2 680 ΩFeedback resistor Decrease of gain(1)
1. The gain must be higher than 24 dB
Increase of gain
R3 22 kΩIncrease of gain Decrease of gain(1)
R4 2.2 ΩFrequency stability Danger of oscillations
C1 1 µF Input decoupling DC Higher low-frequency cutoff
C2 22 µF Inverting input DC
decoupling
Increase of switch
ON/OFF noise Higher low-frequency cutoff
C3, C4 100 nF Supply voltage bypass Danger of oscillation
C5, C6 220 µF Supply voltage bypass Danger of oscillation
C7 0.47 µF Frequency stability Danger of oscillation
Split-supply application suggestions TDA2050
6/18 Doc ID 1461 Rev 3
2.1 Printed circuit board
The layout shown in Figure 5 should be adopted by the designers. If different layouts are
used, the ground points of input 1 and input 2 must be well decoupled from the ground
return of the output in which a high current flows.
Figure 6. Single-supply typical application circuit
Figure 7. PC board and component layout of single-supply typical application circuit
TDA2050 Single-supply application suggestions
Doc ID 1461 Rev 3 7/18
3 Single-supply application suggestions
The recommended values of the external components are those shown in the application
circuit of Figure 6. Different values can be used. The following table can help the designer.
Table 6. Recommonded values
Note: If the supply voltage is lower than 40 V and the load is 8 ohm (or more), a lower value of C2
can be used (i.e. 22 mF). C7 can be larger than 1000 µF only if the supply voltage does not
exceed 40 V.
Component Recommended
value Purpose Larger than
recommended value
Smaller than
recommended value
R1, R2, R3 22 kΩBiasing resistor
R4 680 ΩFeedback resistor Increase of gain Decrease of gain(1)
1. The gain must be higher than 24 dB
R5 22 kΩDecrease of gain(1) Increase of gain
R6 2.2 ΩFrequency stability Danger of oscillations
C1 2.2 µF Input decoupling DC Higher low-frequency cutoff
C2 100 µF Supply voltage rejection Worse turn-off transient
Worse turn-on delay
C3 1000 µF Supply voltage bypass Danger of oscillations
Worse turn-off transient
C4 22 µF Inverting input DC
decoupling
Increase of switching
ON/OFF Higher low-frequency cutoff
C5 100 nF Supply voltage bypass Danger of oscillations
C6 0.47 µF Frequency stability Danger of oscillations
C7 1000 µF Output DC decoupling Higher low-frequency cutoff
Typical characteristics (split-supply test circuit unless otherwise specified) TDA2050
8/18 Doc ID 1461 Rev 3
4 Typical characteristics (split-supply test circuit
unless otherwise specified)
Figure 8. Output power vs. supply voltage Figure 9. Distortion vs. output power
Figure 10. Output power vs. supply voltage Figure 11. Distortion vs. output power
TDA2050 Typical characteristics (split-supply test circuit unless otherwise specified)
Doc ID 1461 Rev 3 9/18
Figure 12. Distortion vs. frequency Figure 13. Distortion vs. frequency
Figure 14. Quiescent current vs. supply
voltage
Figure 15. Supply voltage rejection vs.
frequency
Typical characteristics (split-supply test circuit unless otherwise specified) TDA2050
10/18 Doc ID 1461 Rev 3
Figure 16. Supply voltage rejection vs.
frequency (single-supply) for
different values of C2 (Figure 6)
Figure 17. Supply voltage rejection vs.
frequency (single-supply) for
different values of C2 (Figure 6)
Figure 18. Total power dissipation and
efficiency vs. output power
Figure 19. Total power dissipation and
efficiency vs. output power
TDA2050 Short-circuit protection
Doc ID 1461 Rev 3 11/18
5 Short-circuit protection
The TDA2050 has an original circuit which limits the current of the output transistors. The
maximum output current is a function of the collector emitter voltage, hence the output
transistors work within their safe operating area. This function can therefore be considered
as being peak power limiting rather than simple current limiting. It reduces the possibility
that the device gets damaged during an accidental short-circuit from AC output to ground.
Thermal shutdown TDA2050
12/18 Doc ID 1461 Rev 3
6 Thermal shutdown
The presence of a thermal limiting circuit offers the following advantages:
1. An overload on the output (even if it is permanent), or an above-limit ambient
temperature can be easily tolerated since Tj cannot be higher than 150 °C.
2. The heatsink can have a smaller factor of safety compared with that of a conventional
circuit. There is no possibility of device damage due to high junction temperature. If for
any reason, the junction temperature increases up to 150 °C, the thermal shutdown
simply reduces the power dissipation and the current consumption.
The maximum allowable power dissipation depends upon the thermal resistance junction-
ambient. Figure 20 shows this dissipable power as a function of ambient temperature for
different thermal resistances.
Figure 20. Maximum allowable power dissipation vs. ambient temperature
6.1 Mounting instructions
The power dissipated in the circuit must be removed by adding an external heatsink. Thanks
to the pentawatt package, the heatsink mounting operation is very simple, a screw or a
compression spring (clip) being sufficient. Between the heatsink and the package it is better
to insert a layer of silicon grease, to optimize the thermal contact; no electrical isolation is
needed between the two surfaces. Figure 21 shows an example of a heatsink.
TDA2050 Thermal shutdown
Doc ID 1461 Rev 3 13/18
6.2 Dimension recommendations
The following table shows the length that the heatsink in Figure 21 must have for several
values of Ptot and Rth.
Table 7. Dimension recommendations
Figure 21. Example of heatsink
Ptot (W) 12 8 6
Length of heatsink (mm) 60 40 30
Rth of heatsink (°C/W) 4.2 6.2 8.3
TDA2050
14/18 Doc ID 1461 Rev 3
Appendix A
A.1 Music power concept
Music power is (according to the IEC clauses n.268-3 of Jan. 83) the maximum 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 1 kHz.
According to this definition our method of measurement comprises the following steps:
●Set the voltage supply at the maximum operating value
●Apply a input signal in the form of a 1 kHz tone burst of 1 sec duration: the repetition
period of the signal pulses is 60 sec
●The output voltage is measured 1 sec from the start of the pulse
●Increase the input voltage until the output signal shows a THD=10%
●The music power is then V2out /RL, where Vout is the output voltage measured in the
condition of point 4 and RL is the rated load impedance
The target of this method is to avoid excessive dissipation in the amplifier.
A.2 Instantaneous power
Another power measurement (maximum instantaneous output power) was proposed by the
IEC in 1988 (IEC publication 268-3 subclause 19.A). We give here only a brief extract of the
concept, and a circuit useful for the measurement. The supply voltage is set at the maximum
operating value.
The test signal consists of a sinusoidal signal whose frequency is 20 Hz, to which are added
alternate positive and negative pulses of 50 µs duration and 500 Hz repetition rate. The
amplitude of the 20 Hz signal is chosen to drive the amplifier to its voltage clipping limits,
while the amplitude of the pulses takes the amplifier alternately into its current-overload
limits. A circuit for generating the test signal is given in Figure 22.
The load network consists of a 40 µF capacitor, in series with a 1 ohm resistor. The
capacitor limits the current due to the 20 Hz signal to a low value, whereas for the short
pulses the effective load impedance is of the order of 1 ohm, and a high output current is
produced.
Using this signal and load network the measurement may be made without causing
excessive dissipation in the amplifier. The dissipation in the 1 ohm resistor is much lower
than a rated output power of the amplifier, because the duty-cycle of the high output current
is low. By feeding the amplifier output voltage to the Xplates of an oscilloscope, and the
voltage across the 1 ohm resistor (representing the output current) to the Y=plates, it is
possible to read on the display the value of the maximum instantaneous output power.
The result of this test applied on the TDA2050 is:
Peak power = 100 W typ
TDA2050
Doc ID 1461 Rev 3 15/18
Figure 22. Test circuit for peak power measurement
Package mechanical data TDA2050
16/18 Doc ID 1461 Rev 3
7 Package mechanical data
Figure 23. Pentawatt V package
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.
OUTLINE AND
MECHANICAL DATA
DIM. mm inch
MIN. TYP. MAX. MIN. TYP. MAX.
A 4.80 0.188
C 1.37 0.054
D 2.40 2.80 0.094 0.11
D1 1.20 1.35 0.047 0.053
E 0.35 0.55 0.014 0.022
E1 0.76 1.19 0.030 0.047
F 0.80 1.05 0.031 0.041
F1 1.00 1.40 0.039 0.055
G 3.20 3.40 3.60 0.126 0.134 0.142
G1 6.60 6.80 7.00 0.260 0.267 0.275
H2 10.40 0.41
H3 10.40 0.409
L 17.55 17.85 18.15 0.691 0.703 0.715
L1 15.55 15.75 15.95 0.612 0.620 0.628
L2 21.2 21.4 21.6 0.831 0.843 0.850
L3 22.3 22.5 22.7 0.878 0.886 0.894
L4 1.29 0.051
L5 2.60 3.00 0.102 0.118
L6 15.10 15.80 0.594 0.622
L7 6.00 6.60 0.236 0.260
L9 2.10 2.70 0.083 0.106
L10 4.30 4.80 0.170 0.189
M 4.23 4.5 4.75 0.167 0.178 0.187
M1 3.75 4.0 4.25 0.148 0.157 0.187
V4 40° (Typ.)
V5 90° (Typ.)
DIA 3.65 3.85 0.143 0.151
Pentawatt V
0015981 F
L
L1
A
C
L5
D1 L2
L3
E
M1
M
D
H3
Dia.
L7
L9
L10
L6
F1 H2
F
GG1
E1
F
E
V4
RESIN BETWEEN
LEADS
H2
V5
V4
PENTVME
L4
Weight: 2.00gr
TDA2050
18/18 Doc ID 1461 Rev 3
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