Read Sharp 28JW-74H (serv.man11) Service Manual online
26
28JW-74H
TDA7480 (IC1301,IC1302)
ELECTRICAL CHARACTERISTICS (Refer to the test circuit, V
CC
=
±
14V; R
L
= 8
Ω
; R
S
= 50
Ω
;
R
f
= 12K
Ω
; Demod.. filter L = 60
µ
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
±
16
V
I
q
Total Quiescent Current
R
L
=
∞
; NO LC Filter
25
40
mA
V
OS
Output Offset Voltage
Play Condition
–50
+50
mV
P
O
Output Power
THD = 10%
THD = 1%
THD = 1%
8.5
6
10
7
W
W
W
R
L
= 4
Ω
V
CC
=
±
10.5V
THD = 10%
THD = 1%
THD = 1%
10
7
W
W
W
P
d
(*)
Dissipated Power at 1W Output
Power
Power
R
f
= 12K
Ω
P
Ο
= 1W
1
W
P
DMAX
Maximum Dissipated Power
P
Ο
= 10W THD 10%
R
th-j-amb
= 38°C/W (Area 12cm
2
)
1.8
W
η
Efficiency
≡
P
O
P
O
+
P
D
≡
P
O
P
I
(**)
THD 10%
R
R
th-j-amb
= 38°C/W (Area 12cm
2
)
80
85
%
THD
Total Harmonic Distortion
R
L
= 8
Ω
; P
O
= 0.5W
0.1
%
I
max
Overcurrent Protection
Threshold
Threshold
R
L
= 0
3.5
5
A
T
j
Thermal Shut-down Junction
Temperature
Temperature
150
°C
G
V
Closed Loop Gain
29
30
31
dB
e
N
Total Input Noise
A Curve
f = 20Hz to 22KHz
f = 20Hz to 22KHz
7
12
µ
V
µ
V
R
i
Input Resistance
20
30
K
Ω
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
Ω
F
SW
Switching Frequency
100
120
140
KHz
F
SW_OP
Switching Frequency Operative
Range
Range
100
200
KHz
B
F
Zero Signal Frequency
Constant (***)
Constant (***)
1.4x10
9
Hz
Ω
R
F
Frequency Controller Resistor
Range (****)
Range (****)
7
12
14
K
Ω
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 average power when the amplifier is playing music can be considered roughly 1/10 of the maximum output power. So it is useful
to consider the dissipated power in this condition for thermal dimensioning.
to consider the dissipated power in this condition for thermal dimensioning.
**: P
O
= measured across the load using the following inductor:
COIL 58120 MPPA2 (magnetics) TURNS: 28
∅
1mm
COIL77120 KOOL M
µ
(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 V
12
>5.2V, an input impedance of 10K
Ω
is to be considered.
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