UTC2030
LINEAR INTEGRATED CIRCUIT
YOUWANG ELECTRONICS CO.LTD
1
18W Hi-Fi AMPLIFIER AND
35W DRIVER
DESCRIPTION
The UTC2030 is a monolithic IC in Pentawatt package
intended for use as low frequency class AB amplifier.
With Vsmax=32V it is particularly suited for more reliable
applications without regulated supply and for 35W driver
circuits using lowcost complementary pairs.
The UTC2030 provides high output current and has very
low harmonic and cross-over distortion.
Further the device incorporates a short circuit protection
system comprising an arrangement for automatically limiting
the dissipated power to as to keep the working point of the
output transistors within their safe operating area. A
conventional thermal shut-down system is also included.
TO-220B
ABSOLUTE MAXIMUM RATINGS
(Ta=25
C
)
CHARACTERISTICS SYMBOL VALUE UNITS
Supply Voltage
Vs
20
V
Input Voltage
Vi
Vs
V
Differential input voltage
Vdi
13
V
Peak output current (internally limited)
Io 3.5
A
Total power dissipation at Tcase=90
C
Ptot 20 W
Storage temperature
Tstg
-40~+150
C
junction temperature
Tj
-40~+150
C
TYPICAL APPLICATION
UTC2030
1
2
3
5
4
Vi
+Vs
-Vs
C1
1
F
C2
22
F
C6
100
F
C4
100nF
C7
220nF
C5
100nF
C3
100
F
D1
1N4001
D1
1N4001
R3
22k
R1
22k
R5
C8
R4
1
RL
R3
680
UTC2030
LINEAR INTEGRATED CIRCUIT
YOUWANG ELECTRONICS CO.LTD
2
PIN CONNECTION
1 Non inverting input
2 Inverting input
3 -Vs
4 Output
5 +Vs
ELECTRICAL CHARACTERISTICS
(Refer to the test circuit,Vs=
16V,Ta=25
C
)
PARAMETER SYMBOL
TEST CONDITIONS
MIN
TYP
MAX UNIT
Supply Voltage
Vs
6
18
V
Quiescent drain
current
Id
50
80
mA
Input bias current
Ib
0.2
2
A
Input offset voltage
Vos
Vs=
16v
2
20
mV
Input offset current
Ios
20
200
nA
d=0.5%,
Gv=26dB
f=40 to 15kHz
Output power
Po
R
L
=4
15 18
W
R
L
=8
10 12
W
Power bandwidth
BW
Po=15W, R
L
=4
100
kHz
Slew rate
SR
8
V/
sec
Open loop voltage
gain
Gvo
f=1kHz
80
dB
Closed loop
voltage gain
Gvc
25.5
26
26.5
dB
Total Harmonic
distortion
d
Po=0.1 to 14W, R
L
=4
f=40Hz to 15kHz
0.08
%
Po=0.1 to 14W, R
L
=4
f=1kHz
0.03
%
Total Harmonic
distortion
d
Po=0.1 to 9W, R
L
=8
f=40Hz to 15kHz
0.5
%
Second order CCIF
intermodulation
distortion
d2
Po=4W, R
L
=4
f2-f1=1kHz
0.03
%
Third order CCIF
intermodulation
distortion
d3 f2=14KHz,
f1=15kHz
0.08
%
Input noise voltage
B=curve
A
2
V
Input noise current
B= 22Hz to 22kHz
3
10
V
R
L
=4
, Rg=10k
, B=curve A
Signl to Nois rtio
S/N
Po=15W
106
dB
Po=1W
94
dB
UTC2030
LINEAR INTEGRATED CIRCUIT
YOUWANG ELECTRONICS CO.LTD
3
(continued)
PARAMETER SYMBOL
TEST CONDITIONS
MIN
TYP
MAX UNIT
Input Resistance
(pin 1)
open loop, f=1kHz
0.5
5
M
Supply Voltage
rejection
R
L
=4
, Gv=26dB
Rg=22k
, f=100Hz
54
dB
Thermal Shut-down
junction
temperature
145
C
TEST CIRCUITS
UTC2030
1
2
3
5
4
Vi
+Vs
-Vs
C1
1
F
C2
22
F
C6
220
F
C4
100nF
C7
220nF
C3
100nF
C5
220
F
D1
1N4001
D1
1N4001
R3
22k
R1
13k
R4
1
RL
R3
680
UTC2030
LINEAR INTEGRATED CIRCUIT
YOUWANG ELECTRONICS CO.LTD
4
UTC2030
1
2
3
5
4
Vi
+Vs
C7
220nF
0.1
F
1N4001
100k
R4
1
RL
=4
4.7k
1N4001
100k
2.2
F
100k
2.2
F
100k
22
F
220
F
220
0
F
Fig. 1 Single supply amplifier
UTC2030
LINEAR INTEGRATED CIRCUIT
YOUWANG ELECTRONICS CO.LTD
5
10
2
10
3
10
4
10
5
10
6
10
7
10
1
-60
-20
20
60
100
140
Phase
Gain
Gv
(dB)
180
90
0
Ph
ase
Fig.2 Open loop frequency
response
22
24
26
28
30
32
18
3
6
9
12
15
RL=4
RL=8
Gv=26dB
d=0.5%
f=40 to 15kHz
Fig.3 Output power vs. Supply
voltage
Fig.4 Total harmonic distortion
vs. output power
Fig.5 Two tone CCIF
intermodulation distortion
10
-1
10
0
10
1
10
2
10
-2
10
-2
10
-1
10
0
10
1
10
2
Vs=32V
RL=8
Vs=28V
RL=4
f=15kHz
f=1kHz
Gv=26dB
10
1
10
2
10
-2
10
-1
10
0
10
1
10
2
10
3
10
4
10
5
Order (2f1-f2)
Order (2f2-f1)
Vs=32V
Po=4W
RL=4
Gv=26dB
Fig.6 Large signal frequency
response
Fig.7 Maximum allowable power
dissipation vs. ambient
temperture
10
1
10
2
10
3
10
4
30
5
10
15
20
25
Vs=
15V
RL=4
Vs=
15V
RL=8
-50
0
50
100
150
200
30
5
10
15
20
25
in
fin
ite
h
e
a
ts
in
k
h
e
at
sin
k h
a
vin
g
R
ty
=
2
5
/W
he
ats
ink
ha
vin
g
Rth
=4
/W
hea
tsin
k h
avin
g
Rth
=8
/W
Tamb (
)
Ptot
(W)
Frequency (kHz)
Vo
(Vp-p)
Po (W)
Frequency (Hz)
Po (W)
Vs (V)
Frequency (Hz)
Po
(W)
d
( % )
d
( % )
UTC2030
LINEAR INTEGRATED CIRCUIT
YOUWANG ELECTRONICS CO.LTD
6
UTC2030
1
2
3
5
4
Vi
+Vs
C3
0.2
2
F
R3
56k
RL
=
4
R4
3.3k
1N4
001
C4
10
F
R1
56k
C1
2.2
F
R2
56k
C2
22
F
C5
220
F
/40V
C8
2200
F
R6
1.5
C6
0.
22
F
R5
30k
R7
1.5
1
N
40
01
R8
1
C7
0.22
F
BD908
BD907
Fig. 8 Single supply high power amplifier(UTC2030+BD908/BD907)
TYPICAL PERFORMANCE OF THE CIRCUIT OF FIG. 8
PARAMETER SYMBOL
TEST CONDITIONS
MIN
TYP
MAX UNIT
Supply Voltage
Vs
28
36
V
Quiescent drain
current
Id Vs=32V
50
mA
d=0.5%,R
L
=4
f=40Hz to 15kHz,Vs=32V
32
Output power
Po
d=0.5%,R
L
=4
f=40Hz to 15kHz,Vs=28V
26
W
d=0.5%,f=1kHz,
R
L
=4
,
Vs=32V
35
d=0.5%,R
L
=4
f=1kHz,Vs=28V
28
Voltage Gain
Gv
f=1kHz
19.5
20
20.5
dB
Slew Rate
SR
8
V/
sec
Total harmonic
d
Po=20W,f=1kHz
0.02
%
distortion
Po=20W,f=40Hz to 15kHz
0.05
%
Input sensitivity
Vi
Gv=20dB,Po=20W,
f=1kHz,R
L
=4
890
mV
Signal to Noise
S/N
R
L
=4
,Rg=10k
B=curve A,Po=25W
108
dB
Ratio
R
L
=4
,Rg=10k
B=curve A,Po=25W
100
UTC2030
LINEAR INTEGRATED CIRCUIT
YOUWANG ELECTRONICS CO.LTD
7
22
24
26
28
30
32
5
10
15
20
25
Fig. 10 Output power vs. supply
voltage
Po
(W)
Vs
(V)
10
-1
10
0
10
1
10
-2
10
-1
10
0
f=15kHz
f=1kHz
Vs=32V
RL=4
Gv=20dB
d
(%)
Po
(W)
Fig. 11 Total harmonic distortion
vs. output power
100
250
400
550
700
0
5
10
15
20
Gv=26dB
Gv=20dB
Vi
(mV)
Po
(W)
Fig. 12 Output power vs.
Input level
0
5
10
15
20
0
8
16
24
32
Po
(W)
Ptot
(W)
Complete
Amplifier
BD908/
BD907
UTC2030
Fig. 13 Power dissipation vs.
output power
UTC2030
1
2
3
5
4
Vi
+Vs
-Vs
C1
1
F
C2
22
F
C6
100
F
C4
100nF
C7
220nF
C3
100nF
C5
100
F
D1
1N4001
D2
1N4001
R3
22k
R1
22k
R5
C8
R4
1
RL
R3
680
Fig. 14 Typical amplifier with split power supply
UTC2030
LINEAR INTEGRATED CIRCUIT
YOUWANG ELECTRONICS CO.LTD
8
UTC2030
UTC2030
C1
2.2
F
C6
100
F
C7
100nF
1
2
3
5
4
1
2
3
4
5
C8
0.
22
F
C4
22
F
C9
0.
22
F
C5
22
F
C3
100nF
C2
100
F
R2
22k
R5
22k
R6
680
R9
1
R8
1
R4
680
R3
22k
R7
22k
R1
22k
Vs+
Vs-
IN
RL
8
Fig. 16 Bridge amplifier with split power supply(Po=34W,Vs+=16V,Vs-=16V)
Multiway speaker systems and active boxes
Multiway loudspeaker systems provide the best possible acoustic performance since each loudspeaker is
speciailly designed and optimizied to handle a limited range of frequencies.Commonly,these loudspeaker systems
divide the audio spectrum two or three bands.
To maintain a flat frequency response over the Hi-Fi audio range the bands cobered by each loudspeaker must
overlap slightly.Imbalance between the loudspeakers produces unacceptable results therefore it is important to
ensure that each unit generates the correct amount of acoustic energy for its segmento of the audio spectrum.In
this respect it is also important to know the energy distribution of the music spectrum to determine the cutoff
frequencies of the crossover filters(see Fig. 18).As an example,1 100W three-way system with crossover
frequencies of 400Hz and 3khz would require 50W for tthe woofer,35W for the midrange unit and 15W for the
tweeter.
Both active and passive filters can be used for crossovers but active filters cost significantly less than a good
passive filter using aircored inductors and non-electrolytic capacitors.In addition active filters do not suffer from the
typical defects of passive filters:
--Power less;
--Increased impedance seen by the loudspeaker(lower damping)
--Difficuty of precise design due to variable loudspeaker impedance.
UTC2030
LINEAR INTEGRATED CIRCUIT
YOUWANG ELECTRONICS CO.LTD
9
Obviously, active crossovers can only be used if a power amplifier is provide for each drive unit.This makes it
particularly interesting and economically sound to use monolithic power amplifiers.
In some applications complex filters are not realy necessary and simple RC low-pass and high-pass
networks(6dB/octave) can be recommended.
The result obtained are excellent because this is the best type of audio filter and the only one free from phase and
transient distortion.
The rather poor out of band attenuation of single RC filters means that the lodspeaker must operate linearly well
beyond the crossover frequency to avoid distortion.
A more effective solution,named "Active power Filter" by SGS is shown in Fig. 19.
The proposed circuit can realize combined power amplifiers and 12dB/octave or 18dB octave high-pass or low-
pass filters.
In practive, at the input pins amplifier two equal and in-phase voltages are available, as required for the active
filter operations.
The impedance at the Pin(-) is of the order of 100
,while that of the Pin (+) is very high, which is also what was
wanted.
10
2
10
3
10
4
10
5
10
1
0
20
100
40
60
80
Morden
Music
Spectrum
IEC/DIN NOISE
SPECTRUM
FOR SPEAKER
TESTING
Fig. 18 Power distribution vs.
frequency
Vs+
Vs-
3.3k
100
R2
R1
C1
C2
C3
RL
Fig. 19 Active power filter
R3
The components values calculated for fc=900Hz using a Bessel 3rd Sallen and Key structure are:
C1=C2=C3=22nF,R1=8.2K
,R2=5.6K
,R3=33K
.
Using this type of crossover filter, a complete 3-way 60W active loudspeaker system is shown in Fig. 20.
It employs 2nd order Buttherworth filter with the crossover frequencies equal to 300Hz and 3kHz.
The midrange section consistors of two filters a high pass circuit followed by a low pass network.With Vs=32V the
output power delivered to the woofer is 25W at d=0.06%( 30W at d=0.5%).The power delivered to the midrange
and the tweeter can be optimized in the design phase taking in account the loudspeaker efficiency and
impedance(RL=4
to 8
).
It is quite common that midrange and tweeter speakers have an efficiency 3dB higher than woofers.
Musical instruments amplifiers
Another important field of application for active system is music.
In this area the use of several medium power amplifiers is more convenient than a single high power amplifier,
and it is also more reliable. A typical example(see Fig. 21) consist of four amplifiers each driving a low-cost, 12 inch
loudspeaker. This application can supply 80 to 160W rms.
UTC2030
LINEAR INTEGRATED CIRCUIT
YOUWANG ELECTRONICS CO.LTD
10
Transient inter-modulation distortion(TIM)
Transient inter-modulation distortion is an unfortunate phenomena associated with negative-feedback amplifiers.
When a feedback amplifier receives an input signal which rises very steeply, i.e. contains high-frequency
components, the feedback can arrive too late so that the amplifiers overloads and a burst of
inter-modulation
distortion will be produced as in Fig.22.Since transients occur frequently in music this obviously a problem for the
designed of audio amplifiers. Unfortunately, heavy negative feedback is frequency used to reduce
the total
harmonic distortion of an amplifier, which tends to aggravate the transient inter-modulation(TIM situation.)The best
known
1
2
5
4
3
UTC2030
1
2
5
4
3
UTC2030
1
2
5
4
3
UTC2030
0.
22
F
2200
F
18
nF
33nF
100
F
0.
2
2
F
1N4001
1
F
0.1
F
0.1
F
0.22
F
Vs+
18nF
3.
3nF
100
F
0.22
F
0.1
F
0.1
F
47
F
0.
22
F
100
F
0.
22
F
220
F
0.
22
F
2200
F
1N4001
BD908
BD907
22k
1
4
1.
5
1.
5
3.
3k
22k
22k
68
0
O
10
0
1
22k
22k
6.
8k
3.
3k
10
0
2.2k
Vs+
1N4001
1N4001
1N4001
8
1O
2.2k
12
k
100
22k
8
22k
22k
Vs+
100
F
Vs+
IN
Woofer
Midrange
Tweeter
High-pass
3kHz
High-pass
3kHz
Band-pass
300Hz to 3kHz
Low-pass
300Hz
1N4001
UTC2030
LINEAR INTEGRATED CIRCUIT
YOUWANG ELECTRONICS CO.LTD
11
20 to 40W
Amplifier
20 to 40W
Amplifier
20 to 40W
Amplifier
20 to 40W
Amplifier
PRE
AMPLIFIER
POWER
AMPLIFIER
FEEDBACK
PATH
INPUT
V1
V2
V3
V4
V4
OUTPUT
V1
V2
V3
V4
Fig.21 High power active box for musical
instrument
Fig.22 Overshoot phenomenon in
feedback amplifiers
method for the measurement of TIM consicts of feeding sine waves superimposed onto square wavers,into the
amplifier under test.The output spectrum is then examined using a spectrum analyser and compared to the
input.This method suffers from serious disadvantages:the accuracy is limited, the measurement is a tather delicate
operation and an expensive spectrum analyser is essential.A new approach (see Technical Note 143(Applied by
SGS to monolithic amplifiers measurement is fast cheap,it requires nothing more sophisticated than an
oscilloscope-and sensitive-and it can be used down to the values as low as 0.002% in high power amplifiers.
The "inverting-sawtooth" method of measurement is based on the response of an amplifier to a 20KHz sawtooth
waveform.The amplifier has no difficulty following the slow ramp but it cannot follow the fast edge.The output will
follow the upper line in Fig.23 cutting of the shade area and thus increasing the mean level.If this output signal is
filtered to remove the sawtooth,direct voltage remains which indicates the amount of tIM distortion, although it is
difficult to measure because it is indistingishable from the DC offset of the amplifier.This problem os neatly avoided
in the IS-TIM method by periodically inverting the sawtooth waveform at a low audio frequency as shown in
Fig.24.Inthe case of the sawtooth in Fig. 25 the means level was increased by the TIM distortion, for a sawtooth in
the other direction the opposite is ture.
m2
m1
SR(V/
s)
Input
Signal
Filtered
Output
Siganal
Fig.23 20kHz sawtooth waveform Fig.24 Inverting sawtooth waveform
UTC2030
LINEAR INTEGRATED CIRCUIT
YOUWANG ELECTRONICS CO.LTD
12
The result is an AC signal at the output whole peak-to-peak value is the TIM voltage,which can be measured
easily with an oscilloscope.If the peak-topeak value of the signal and the peak-to-peak of the inverting sawtooth are
measured,the TIM can be found very simply from:
TIM
VOUT
Vsawtooth
* 100
=
10
-1
10
0
10
1
10
2
10
-2
10
-1
10
0
10
1
UTC2030
BD908/907
Gv=26dB
Vs=32V
RL=4
RC Filter fc=30kHz
Fig. 25 TIM distortion Vs.
Output Power
Po(W)
TIM(%)
10
-1
10
0
10
1
10
2
Vo(Vp-p)
10
-1
10
0
10
1
10
2
RC Filter fc=30kHz
Fig. 26 TIM design
diagram(fc=30kHz)
TI
M=
0.
1%
TI
M
=0
.01
%
TI
M=
1%
SR(V/
)
In Fig.25 The experimental results are shown for the 30W amplifier using the UTC2030 as a driver and a low-cost
complementary pair.A simple RC filter on the input of the amplifier to limit the maxmium signal slope(SS) is an
effective way to reduce TIM.
The Digram of Fig.26 originated by SGS can be used to find the Slew-Rate(SR) required for a given output power
or voltage and a TIM design target.
For example if an anti-TIM filter with a cutoff at 30kHz is used and the max.Peak to peak output voltage is 16V then,
referring to the diagram, a Slew-Rate of 6V/
s is necessary for 0.1% TIM.
As shown Slew-Rates of above 10V/
s do not contribute to a further reduction in TIM.
Slew-Rates of 100V/
s are not only useless but also a disadvantage in Hi-Fi audio amplifiers because they tend to
turn the amplifier into a radio receiver.
Power Supply
Using monolithic audio amplifier with non regulated supply correctly.In any working case it must provide a supply
voltage less than the maximum value fixed by the IC breakdown voltage.
It is essential to take into account all the working conditions, in particular mains fluctuations and supply voltage
variations with and without load.The UTC2030(Vsmax=32V) is particularly suitable for substitution of the standard
IC power amplifiers(with Vsmax=28V) for more reliable applications.
An example, using a simple full-wave rectifier followed by a capacitor filter, is shown in the table and in the
diagram of Fig.27.
A regulated supply is not usually used for the power output stages because of its dimensioning must be done
taking into account the power to supply in signal peaks.They are not only a small percentage of the total music
signal, with consequently large overdimensioning of the circuit.
Even if with a regulated supply higher output power can be obtained(Vs is constant in all working conditions),the
additional cost and power dissipation do not usually justify its use.using non-regulated supplies,there are fewer
designe restriction.In fact,when signal peaks are present, the capacitor filter acts as a flywheel supplying the
required energy.
UTC2030
LINEAR INTEGRATED CIRCUIT
YOUWANG ELECTRONICS CO.LTD
13
In average conditions,the continuous power supplied is lower.The music power/continuous power ratio is greater in
case than for the case of regulated supplied,with space saving and cost reduction.
0
0.4
0.8
1.2
1.6
2.0
18
20
22
24
26
Vo(V)
Io(A)
Fig.27 DC characteristics of
50W non-regulated supply
Vo
3300
F
220V
0
2
4
Ripple
(Vp-p)
Ripple
Vout
Mains(220V) Secondary
voltage
DC output Voltage(Vo)
Io=0
Io=0.1A
Io=1A
+20% 23.0V 34.5V 33.6V 30.0V
+15% 22.1V 33.1V 32.2V 28.6V
+10% 21.1V 31.7V 30.8V 27.3V
--
19.2V 29.0V 28.0V 24.8V
-10% 17.3V 25.9V 25.2V 22.2V
-15% 16.3V 24.5V 23.8V 20.8V
-20% 15.3V 23.0V 22.4V 19.4V
Short Circuit Protection
The UTC2030 has an original circuit which limits the current of the output transistors.This function can 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 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 above limit ambient temperture can be easily supported
since the Tj can not be higher than 150
C
2).The heat-sink can have a smaller factor of safety compared with that of a convential circuit,There is no possibity
of device damage due to high junction temperature increase up to 150, the thermal shut-down simply reduces the
power dissipation and the current consumption.
UTC2030
LINEAR INTEGRATED CIRCUIT
YOUWANG ELECTRONICS CO.LTD
14
APPLICATION SUGGESTION
The recommended values of the components are those shown on application circuit of Fig.14. Different values can
be used.The following table can help the designer.
Component Recommended
value
Purpose Large
than
recommended value
Large than
recommended value
R1
22K
Closed loop gaon
setting.
Increase of Gain
Decrease of Gain
R2
680
Closed loop gaon
setting.
Decrease of Gain
Increase of Gain
R3
22K
Non inverting input
biasing
Increase of input
impedance
Decrease of input
impedance
R4
1
Frequency stacility
Danger of oscillation
at high frequencies
with inductive loads.
R5
3R2
Upper frequency
cutoff
Poor high frequencies
attenuation
Dange of oscillation
C1
1
F
Input DC decoupling
Increase of low
frequencies cutoff
C2
22
F
Inverting DC
decoupling
Increase of low
frequencies cutoff
C3,C4
0.1
F
Supply voltage
bypass
Dange of oscillation
C5,C6
100
F
Supply voltage
bypass
Dange of oscillation
C7
0.22
F
Frequency stability
Larger
bandwidth
C8
1/(2
*B*R1)
Upper frequency
cutoff
smaller bandwidth
Larger bandwidth
D1,D2
1N4001
To protect the device
against output voltage
spikes.
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