IDT 89HPES24NT24G2 Datasheet
22 of 35 December 17, 2013
Thermal Considerations
This section describes thermal considerations for the PES24NT24G2 (19mm
2
FCBGA324 package). The data in Table 19 below contains informa-
tion that is relevant to the thermal performance of the PES24NT24G2 switch.
Note: It is important for the reliability of this device in any user environment that the junction temperature not exceed the T
J(max)
value
specified in Table 19. Consequently, the effective junction to ambient thermal resistance (
JA
) for the worst case scenario must be
maintained below the value determined by the formula:
JA
= (T
J(max)
- T
A(max)
)/P
Given that the values of T
J(max)
, T
A(max)
, and P are known, the value of desired
JA
becomes a known entity to the system designer. How to
achieve the desired
JA
is left up to the board or system designer, but in general, it can be achieved by adding the effects of
JC
(value
provided in Table 19), thermal resistance of the chosen adhesive (
CS
), that of the heat sink (
SA
), amount of airflow, and properties of the
circuit board (number of layers and size of the board). It is strongly recommended that users perform their own thermal analysis for their own
board and system design scenarios.
Symbol Parameter Value Units Conditions
T
J(max)
Junction Temperature 125
o
CMaximum
T
A(max)
Ambient Temperature 70
o
C Maximum for commercial-rated products
85
o
C Maximum for industrial-rated products
JA(effective)
Effective Thermal Resistance, Junction-to-Ambient
16.8
o
C/W Zero air flow
10.1
o
C/W 1 m/S air flow
9.2
o
C/W 2 m/S air flow
JB
Thermal Resistance, Junction-to-Board 4.1
o
C/W
JC
Thermal Resistance, Junction-to-Case 0.3
o
C/W
P Power Dissipation of the Device 6.82 Watts Maximum
Table 19 Thermal Specifications for PES24NT24G2, 19x19 mm FCBGA324 Package
