Data Sheet

Ethernet Controller I210 —Thermal Considerations
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13.3 Thermal Management Importance
The objective of thermal management is to ensure that all system component temperatures are
maintained within their functional limits. The functional temperature limit is the range in which the
electrical circuits are expected to meet specified performance requirements. Operation outside the
functional limit can degrade system performance, cause logic errors, or cause device and/or system
damage. Temperatures exceeding the maximum operating limits can result in irreversible changes in
the device operating characteristics. Also note that sustained operation at a component maximum
temperature limit can affect long-term device reliability.
13.4 Terminology and Definitions
The following is a list of the terminology that is used in this section and their definitions:
QFN: Quad Flatpack No leads: A surface-mount package using a QFN structure whose PCB-
interconnect method consists of Pb-free perimeter lands and an exposed thermal pad on the
interconnect side of the package that are attached to a near chip-scale size substrate.
2s2p: A 4-layer board with two signal layers on the outside and two internal plane layers.
Thermal Resistance: The resulting change in temperature per watt of heat that passes from one
reference point to another.
Junction: Refers to a P-N (diode) junction on the silicon. In this document, it is used as a temperature
reference point (for example,
өJA refers to the "junction" to "ambient" thermal resistance).
Ambient: Refers to the local ambient temperature of the bulk air approaching the component. It can
be measured by placing a thermocouple approximately 1 inch upstream from the component edge.
Lands: The pads on the PCB to which BGA balls are soldered.
PCB: Printed circuit board.
Printed Circuit Assembly (PCA): A PCB that has components assembled on it.
Thermal Design Power (TDP): The estimated maximum possible/expected power generated in a
component by a realistic application. TDP is a system design target associated with the maximum
component operating temperature specifications. Maximum power values are determined based on
typical DC electrical specification and maximum ambient temperature for a worst-case realistic
application running at maximum utilization.
LFM: A measure of airflow velocity in Linear Feet per Minute.
ө
JA
(Theta JA): Thermal resistance from component junction to ambient, °C/W.
Ψ
JT
(Psi JT): Junction-to-top (of package) thermal characterization parameter, °C/W. Ψ
JT
does not
represent thermal resistance, but instead is a characteristic parameter that can be used to convert
between T
j
and T
case
when knowing the total TDP. Ψ
JT
is easy to characterize in simulations or
measurements and is defined as follows: This parameter can vary with environmental
conditions, such as airflow, thermal solution presence, and design