STK433-070-E
[Example]
When the IC supply voltage, V , is 29V and R is 6Ω, the total power dissipation, Pd, within the hybrid IC, will
CC
L
be a maximum of 60W at 1kHz for a continuous sine wave signal according to the Pd-P characteristics.
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For the music signals normally handled by audio amplifiers, a value of 1/8P max is generally used for Pd as an
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estimate of the power dissipation based on the type of continuous signal. (Note that the factor used may differ
depending on the safety standard used.)
This is:
Pd ≈ 46W
(when 1/8P max. = 7.5W, P max. = 50W).
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The number of power transistors in audio amplifier block of these hybrid ICs, N, is 4, and the thermal resistance per
transistor, θj-c, is 3.5°C/W. Therefore, the required heat sink thermal resistance for a guranteed ambient temperature,
Ta, of 50°C will be as follows.
From formula (1)'
θc-a < (125 − 50)/46
< 1.63
From formula (2)'
θc-a < (150 − 50)/46 − 3.5/4
< 1.30
Therefore, the value of 1.30°C/W, which satisfies both of these formulae, is the required thermal resistance of the heat
sink.
Note that this thermal design example assumes the use of a constant-voltage power supply, and is therefore not a
verified design for any particular user’s end product.
STK433-000 Series Standby Control, Mute Control, Load-short Protection & DC
offset Protection application
STK433-000 series
(*1) The voltage applied to the Stand-by pin (#13) must not exceed the
maximum rated value (VST max).
Ch1
Ch1
Ch2
Ch2
Ch1
IN
Ch1
NF
Ch2
NF
Ch2
IN
-PRE -V
1
+V
+PRE SUB GND
ST-BY
13
OUT OUT OUT OUT
CC
CC
2
3
4
6
7
8
9
10
11
12
14
15
5
1kΩ
56kΩ
6.8kΩ
56kΩ
6.8kΩ
Stand-by Control (ex)
H: Operation Mode (+5V)
L: Stand-by Mode (0V)
33kΩ
(*1) R1
ex) 5.1kΩ
33μF
2kΩ
/10V
Ch2 IN
Load short
protection
circuit
10kΩ
10kΩ
GND
22kΩ
56kΩ
Ch1 IN
Latch up
circuit
10kΩ
1kΩ
0.1μF
+V
CC
V1
2.2kΩ
Mute Control
H: Single Mute
L: Normal
(*4)
R2
10kΩ 100kΩ
Ch2 OUT
GND
-V
82kΩ
+5V
Standby
Control
GND
GND
22μF
22μF
100
kΩ
CC
+5V
82kΩ
Mute
Control
Ch1 OUT
DC offset protection
MUTE
PLAY
ST-BY
MUTE
ST-BY
(*1) R1 is changed depending on the power-supply voltage (-V ).
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Please set resistance (R1) to become “V1 ≈ 0V” by the following calculation types.
No. A1488-8/11
SANYO [ SANYO SEMICON DEVICE ]
