7. Thermal Considerations
7.1 Thermal Resistance Data
The following table summarizes the thermal resistance data depending on the package.
Table 7-1. Thermal Resistance Data
Package Type θ
JA
[°C/W] θ
JC
[°C/W]
14-pin SOIC150 (SVQ) 58 26
Related Links
Junction Temperature
7.2 Junction Temperature
The average chip-junction temperature, T
J
, in °C can be obtained from the following:
1. T
J
= T
A
+ (P
D
x θ
JA
)
2. T
J
= T
A
+ (P
D
x (θ
HEATSINK
+ θ
JC
))
where:
• θ
JA
= Package thermal resistance, Junction-to-ambient (°C/W), see Thermal Resistance Data
• θ
JC
= Package thermal resistance, Junction-to-case thermal resistance (°C/W), see Thermal
Resistance Data
• θ
HEATSINK
= Thermal resistance (°C/W) specification of the external cooling device
• P
D
= Device power consumption (W)
• T
A
= Ambient temperature (°C)
From the first equation, the user can derive the estimated lifetime of the chip and decide if a cooling
device is necessary or not. If a cooling device is to be fitted on the chip, the second equation should be
used to compute the resulting average chip-junction temperature T
J
in °C.
Related Links
Thermal Resistance Data
ATtiny214/414/814
© 2017 Microchip Technology Inc.
Datasheet Preliminary Summary
DS40001932A-page 12
