CPC1708
PRELIMINARY
2 Thermal Characteristics
Parameter
Conditions
Symbol
RθJC
Minimum
Typical Maximum Units
Thermal Resistance (Junction to Case)
Thermal Resistance (Junction to Ambient)
Junction Temperature (Operating)
-
-
-
-
45
-
0.35
-
°C/W
°C/W
°C
Free Air
-
RθJA
T
-40
100
J
2.1 Thermal Management
Device high current characterization was performed using Kunze heat sink KU 1-159, phase change thermal interface
material KU-ALC 5, and transistor clip KU 4-499/1. This combination provided an approximate junction-to-ambient
thermal resistance of 12.5°C/W.
2.2 Heat Sink Calculation
Higher load currents are possible by using lower thermal resistance heat sink combinations.
Heat Sink Rating
2
(TJ - TA) IL(99)
RθCA
=
- RθJC
IL2 • PD(99)
TJ = Junction Temperature (°C), TJ ≤ 100°C *
TA = Ambient Temperature (°C)
I
L(99) = Load Current with Case Temperature @ 99°C (ADC)
IL = Desired Operating Load Current (ADC), IL ≤ IL(MAX)
RθJC = Thermal Resistance, Junction to Case (°C/W) = 0.35°C/W
RθCA = Thermal Resistance of Heat Sink & Thermal Interface Material , Case to Ambient (°C/W)
PD(99) = Maximum power dissipation with case temperature held at 99ºC = 2.86W
* Elevated junction temperature reduces semiconductor lifetime.
3
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