STK400-020 Sanyo Semiconductor Corporation, STK400-020 Datasheet - Page 7

• Manufacturer Part Number: STK400-020
• Description: 3-channel af Power Amplifier (15W+15W+15W)
• Manufacturer: Sanyo Semiconductor Corporation

External Circuit Diagram
Heat Radiation Design Considerations
The radiator thermal resistance c-a required for total substrate power dissipation Pd in the STK400-020 is determined as
follows:
Condition 1: IC substrate temperature Tc not to exceed 125°C.
Condition 2: Power transistor junction temperature Tj not to exceed 150°C.
Expressions (1) and (2) can be rewritten based on c-a to yield:
The required radiator thermal resistance will satisfy both of these expressions.
From expressions (1)' and (2)', the required radiator thermal resistance can be determined once the following
specifications are known:
The total substrate power dissipation when STK400-020 V
is a maximum of 41 W (Fig. 1). In general, when this sort of continuous signal is used for estimation of power
dissipation, the Pd used is 1/10th of P
Pd x c-a+Ta <125°C ······························· (1)
Pd x c-a+Pd/N x j-c+Ta<150°C·············(2)
•
•
•
Pd=23.5 W (1/10 P
c-a<(125–Ta)/Pd ······································(1)'
c-a<(150–Ta)/Pd– j-c/N··························(2)'
Supply voltage
Load resistance
Assured ambient temperature Ta
where Ta is set assured ambient temperature.
where N is the number of power transistors and j-c the thermal resistance per power transistor chip.
However, power transistor power dissipation is Pd equally divided by N units.
O
max=during 1.5 W)
O
max (slight variation depending on safety standard).
V
R
L
CC
STK400-020
CC
is ±20 V and R
L
is 6 Ω, for a continuous sine wave signal,
No. 4830-7/10