STK4067 查看數據表（PDF） - SANYO -> Panasonic
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STK4067 Datasheet PDF : 8 Pages
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STK4067
Sample STK4067 Heat Sink Design
The radiator thermal resistance θc-a required for total substrate power dissipation Pd in the STK4067 is determined as:
Condition 1: IC substrate temperature Tc not to exceed 110°C.
Pd x θc-a+Ta <110°C ······························· (1)
where Ta is set assured ambient temperature.
Condition 2: Power transistor junction temperature Tj not to exceed 150°C.
Pd x θc-a+Pd/N x θj-c+Ta<150°C·············(2)
where N is the number of power transistors and θj-c is the thermal resistance per power transistor chip.
However, power transistor power consumption is Pd equally divided by N units.
Expressions (1) and (2) can be rewritten based on θc-a to yield:
θc-a<(110–Ta)/Pd ······································(1)'
θc-a<(150–Ta)/Pd–θj-c/N ··························(2)'
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:
• Supply voltage
VCC
• Load resistance
RL
• Assured ambient temperature Ta
The total substrate power consumption when STK4067 VCC is ±13.2 V and RL is 2 Ω, for a continuous sine wave
signal, is a maximum of 19.3W (Fig. 2).
The STK4067 has four power transistors, so the thermal resistance per transistor θj-c is 1.6°C / W. With an assured
ambient temperature Ta of 50°C, the required radiator thermal resistance θc-a would be:
From expression (1)' θc-a <(110–50)/19.3
<3.1
From expression (2)' θc-a <(150–50)/19.3–1.6/4
<4.78
To satisfy both, 3.1°C/W is the required radiator thermal resistance.
Figure 1 illustrates Pd - PO when the VCC of STK4067 is 13.2V and RL is functioning at 1Ω.
Pd max= 34.8W
From expression (1)' θc-a <(110–50)/34.8
<1.72
From expression (2)' θc-a <(150-50)/34.8–1.6/4
<2.47
To satisfy both, 1.72°C/W is the required radiator thermal resistance.
Similar to figure 3 when the STK4067’s VCC is 13.2 V and RL is 4Ω.
Pd max= 12W
From expression (1)' θc-a <(110–50)/12
<5
From expression (2)' θc-a <(150-50)/12–1.6/4
<7.93
To satisfy both, 5°C / W is the required radiator thermal resistance. This design example is based on a fixed voltage
supply, and will require verification within your specific set environment.
No. 4376-5/8
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