STK4172II Sanyo, STK4172II Datasheet - Page 8

• Manufacturer Part Number: STK4172II
• Description: AF Power Amplifier
• Manufacturer: Sanyo

In an actual application where a music signal is used, it is impractical to estimate the power dissipation based on the con-
tinuous signal as shown above, because too large a heat sink must be used. It is reasonable to estimate the power dissipa-
tion as 1/10 Po max. (EIAJ).
That is, Pd = 35W at 8 , Pd = 49W at 4
Thermal resistance c-a of a heat sink for this IC power dissipation (Pd) is fixed under conditions 1 and 2 shown below.
Assuming that the power dissipation is shared equally among the four power transistors (2 channels
tance j-c is 1.8 C/W and
Thermal resistance c-a of a heat sink must satisfy ine-
qualities (1) and (3).
Figure 3 shows the relation between Pd and c-a given
from (1) and (3) with Ta as a parameter.
[Example] The thermal resistance of a heat sink is
This catalog provides information as of July, 1997. Specifications and information herein are subject to change without notice.
No products described or contained herein are intended for use in surgical implants, life-support systems, aerospace equipment, nuclear
power control systems, vehicles, disaster/crime-prevention equipment and the like, the failure of which may directly or indirectly cause injury,
death or property loss.
Anyone purchasing any products described or contained herein for an above-mentioned use shall:
Information (including circuit diagrams and circuit parameters) herein is for example only; it is not guaranteed for volume production. SANYO
believes information herein is accurate and reliable, but no guarantees are made or implied regarding its use or any infringements of
intellectual property rights or other rights of third parties.
Accept full responsibility and indemnify and defend SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors and all their
officers and employees, jointly and severally, against any and all claims and litigation and all damages, cost and expenses associated
with such use:
Not impose any responsibility for any fault or negligence which may be cited in any such claim or litigation on SANYO ELECTRIC CO.,
LTD., its affiliates, subsidiaries and distributors or any of their officers and employees, jointly or severally.
obtained when the ambient temperature speci-
fied for a stereo amplifier is 50 C.
Assuming V
V
R
R
The thermal resistance of a heat sink is
obtained from Figure 3.
R
R
Tj when a heat sink is used is obtained from
(3).
R
R
L
L
L
L
L
L
CC
Condition 1: Tc = Pd
Condition 2: Tj= Pd
= 8 : Pd1 = 35W at 1/10 Po max.
= 4 : Pd2 = 49W at 1/10 Po max.
= 8 : c-a1 = 2.15 C/W
= 4 : c-a2 = 1.53 C/W
= 8 : Tj = 141 C
= 4 : Tj = 147 C
= 29V, R
CC
L
= 32V, R
where
where
Pd
= 4 ,
c-a + 1.8/4) + Ta 150 C........................................ (3)
Ta : Specified ambient temperature
Tc : Operating substrate temperature
Tj : Junction temperature of power transistor
L
= 8 ,
c-a) + Pd/4
c-a + Ta 125 C............................................... (1)
STK4172 II
j-c) + Ta 150 C..................... (2)
Figure 3. STK4172II c-a – Pd
IC Power dissipation, Pd - W
2), thermal resis-
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