TDA7481
18W MONO CLASS-D AMPLIFIER
18W OUTPUT POWER:
R
L
= 8
/4
; THD = 10%
HIGH EFFICIENCY
WIDE SUPPLY VOLTAGE RANGE (UP TO
25V)
SPLIT SUPPLY
OVERVOLTAGE PROTECTION
ST-BY AND MUTE FEATURES
SHORT CIRCUIT PROTECTION
THERMAL OVERLOAD PROTECTION
DESCRIPTION
The TDA7481 is an audio class-D amplifier as-
sembled in Multiwatt15 package specially de-
signed for high efficiency applications mainly for
TV and Home Stereo sets.
February 1998
L1 60
H
8
+
-
+
-
PWM
PRE
9
5
C2 0.33
F
IN1
C4 4.7nF
FEEDCAP
OUT
BOOT
C11
100nF
C12
560pF
R5
150
C14
470nF
3
1
VREG
C15
100nF
R4 12K
12
2
C10
2200
F
C9
100nF
SGN-GND
7
MUTE
ST-BY
10
13
11
+VCC
ST-BY/
MUTE
C1
2.2
F
R3
30K
R2
10K
V
CC SIGN
C7
2200
F
IN1
D96AU534C
C6
100nF
C3
1nF
R1
10K
+5V
V
CC POW
4
N.C.
C5 100nF
BOOTDIODE
6
8
14,15
-V
CC SIGN
FREQ
-V
CC POW
-VCC
-VCC
(Pin 14,15)
C8
270pF
(R
F
)
Figure 1: Test and Application Circuit.
ORDERING NUMBER: TDA7481
Multiwatt15
1/6
ABSOLUTE MAXIMUM RATINGS
Symbol
Parameter
Value
Unit
V
CC
DC Supply Voltage
25
V
P
tot
Power Dissipation T
case
= 70C
35
W
T
stg
, T
j
Storage and Junction Temperature
40 to 150
C
V
FREQ
Maximum Voltage Across RF (pin 6)
8
V
T
op
Operating Temperature Range
0 to 70
C
ESD
Max ESD On Pins
1.2
KV
THERMAL DATA
Symbol
Parameter
Typ.
Max.
Unit
R
th j-case
Thermal Resistance Junction-case
1.8
2.5
C/W
PIN FUNCTIONS
N.
Name
Function
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
OUT
BOOTDIODE
BOOT
NC
FEEDCAP
FREQ
SGN-GND
V
CC
SIGN
IN
ST-BY/MUTE
+V
CC
SIGN
VREG
+V
CC
POW
-V
CC
POW
-V
CC
POW
PWM OUTPUT
BOOTSTRAP DIODE ANODE
BOOTSTRAP
NOT CONNECTED
FEEDBACK INTEGRATING CAPACITOR
SETTING FREQUENCY RESISTOR
SIGNAL GROUND
SIGNAL NEGATIVE SUPPLY
INPUT
CONTROL STATE PIN
POSITIVE SIGNAL SUPPLY
INTERNAL VOLTAGE REGULATOR
POSITIVE POWER SUPPLY
NEGATIVE POWER SUPPLY (to be connected to pin 13 via CS)
NEGATIVE POWER SUPPLY (to be connected to pin 13 via CS)
1
2
3
4
5
6
7
9
10
11
8
+V
CC SIGN
ST-BY/MUTE
IN
-V
CC SIGN
SGN-GND
FREQ
FEEDCAP
N.C.
BOOT
BOOTDIODE
OUT
TAB CONNECTED TO PIN 8
13
14
15
12
-V
CC POW
-V
CC POW
+V
CC POW
VREG
D96AU535A
PIN CONNECTION (Top view)
TDA7481
2/6
ELECTRICAL CHARACTERISTICS (Refer to the test circuit, V
CC
=
18V; R
L
= 8
; R
S
= 50
;
R
F
= 12K
; Demod.. filter L = 60
H, C = 470nF; f = 1KHz; T
amb
= 25`C unless otherwise specified.)
Symbol
Parameter
Test Condition
Min.
Typ.
Max.
Unit
V
S
Supply Range
10
25
V
I
q
Total Quiescent Current
R
L
=
, no LC filter
35
55
mA
V
OS
Output Offset Voltage
PLAY condition
70
-30
10
mV
P
O
Output Power
THD = 10%
THD = 1%
15
10
18
13
W
W
P
O
Output Power
V
CC
=
15V; R
L
= 4
THD = 10%
THD = 1% (*)
18
13
W
W
P
D
Maximum Dissipated Power
V
CC
=
18V; R
L
= 8
;
R
f
= 12K
P
= 18W THD 10%
3.5
W
Efficiency
P
O
P
O
+
P
D
P
O
P
I
(**)
V
CC
=
18V; R
L
= 8
;
R
f
= 12K
P
= 18W THD 10%
85
%
THD
Total Harmonic Distortion
R
L
= 8
; P
O
= 1W
0.1
%
I
max
Overcurrent Protection
Threshold
R
L
= 0
3.5
5
A
T
j
Thermal Shut-down Junction
Temperature
150
C
G
V
Closed Loop Gain
29
30
31
dB
e
N
Total Input Noise
A Curve
f = 20Hz to 22KHz
7
12
V
V
V
CCTOT MAX
Maximum Total V
CC
Protection
50
V
R
i
Input Resistance
20
30
k
SVR
Supply Voltage Rejection
f = 100Hz; V
r
= 0.5
46
60
dB
T
r
, T
f
Rising and Falling Time
50
ns
R
DSON
Power Transistor on Resistance
0.4
F
SW-OP
Switching Frequency Operative
Range
100
200
KHz
F
SW
Switching Frequency
100
120
140
KHz
B
F
Zero Signal Frequency
Constant (***)
1.4x10
9
Hz
R
F
Frequency Controller Resistor
Range (****)
7
12
14
K
MUTE & STAND-BY FUNCTIONS
V
ST-BY
Stand-by range
0.8
V
V
MUTE
Mute Range
1.8
2.5
V
V
PLAY
Play Range (1)
4
V
A
MUTE
Mute Attenuation
60
80
dB
I
qST-BY
Quiescent Current @ Stand-by
3
5
mA
*: The output LC filter must be changed to: L = 30
H; C = 1
F
**: P
O
= measured across the load using the following inductor:
COIL 58120 MPPA2 (magnetics) TURNS: 28
1mm
***: The zero-signal switching frequency can be obtained using the following expression: F
SW
= B
F
/R
F
****: The maximum value of R
F
is related to the maximum possible value for the voltage drop on R
F
itself
(1) for V10 >5.2V, an input impedance of 10K
is to be considered
TDA7481
3/6
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