VN5770AK-E Package and thermal data
Doc ID 13228 Rev 6 25/34
a. See Figure 38. For more detailed information see Table 17 and Table 18.
Table 17. Thermal calculations in clockwise and anti-clockwise operation in
steady-state mode
HS
1
HS
2
LS
3
LS
4
T
jHS12
T
jLS3
T
jLS4
ON OFF OFF ON
P
dHS1
x R
thHS
+ P
dLS4
x
R
thHSLS
+ T
amb
P
dHS1
x R
thHSLS
+
P
dLS4
x R
thLSLS
+ T
amb
P
dHS1
x R
thHSLS
+
P
dLS4
x R
thLS
+ T
amb
OFF ON ON OFF
P
dHS2
x R
thHS
+ P
dLS3
x
R
thHSLS
+ T
amb
P
dHS2
x R
thHSLS
+
P
dLS3
x R
thLS
+ T
amb
P
dHS2
x R
thHSLS
+
P
dLS3
x R
thLSLS
+ T
amb
Table 18. Thermal resistances definitions
(1)
1. values dependent on PCB heatsink area
R
thHS
= R
thHS1
= R
thHS2
High-side chip thermal resistance junction to ambient
(HS
1
or HS
2
in ON state)
R
thLS
= R
thLS3
= R
thLS4
Low-side chip thermal resistance junction to ambient
R
thHSLS
= R
thHS1LS4
= R
thHS2LS3
Mutual thermal resistance junction to ambient between
high-side and low-side chips
R
thLSLS
= R
thLS3LS4
Mutual thermal resistance junction to ambient between
low-side chips
Table 19. Single pulse thermal impedance definitions
(1)
1. values dependent on PCB heatsink area
Z
thHS
High-side chip thermal impedance junction to ambient
Z
thLS
= Z
thLS3
= Z
thLS4
Low-side chip thermal impedance junction to ambient
Z
thHSLS
= Z
thHS12LS3
= Z
thHS12LS4
Mutual thermal impedance junction to ambient
between high-side and low-side chips
Z
thLSLS
= Z
thLS3LS4
Mutual thermal impedance junction to ambient
between low-side chips
Table 20. Thermal calculations in transient mode
(1)
1. Calculation is valid in any dynamic operating condition. Pd values set by user.
T
jHS12
Z
thHS
x P
dHS12
+ Z
thHSLS
x (P
dLS3
+ P
dLS4
) + T
amb
T
jLS3
Z
thHSLS
x P
dHS12
+ Z
thLS
x P
dLS3
+ Z
thLSLS
x P
dLS4
+ T
amb
T
jLS4
Z
thHSLS
x P
dHS12
+ Z
thLSLS
x P
dLS3
+ Z
thLS
x P
dLS4
+ T
amb
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