TSI-2 AGERE [Agere Systems], TSI-2 Datasheet - Page 16

• Manufacturer Part Number: TSI-2
• Description: 2k x 2k Time-Slot Interchanger
• Manufacturer: AGERE [Agere Systems]

TSI-2
2k x 2k Time-Slot Interchanger
3.4 Thermal Parameters (Definitions and Values)
System and circuit board level performance depends not only on device electrical characteristics, but also on device thermal
characteristics. The thermal characteristics frequently determine the limits of circuit board or system performance, and they
can be a major cost adder or cost avoidance factor. When the die temperature is kept below 125 °C, temperature-activated
failure mechanisms are minimized. The thermal parameters that Agere provides for its packages help the chip and system
designer choose the best package for their applications, including allowing the system designer to thermally design and in-
tegrate their systems.
It should be noted that all the parameters listed below are affected, to varying degrees, by package design (including paddle
size) and choice of materials, the amount of copper in the test board or system board, and system airflow.
Θ
Θ
Θ
Θ
Θ
Θ
tunnel with forced air convection. Θ
roughly correspond to 1 m/s and 2.5 m/s (respectively). Θ
Θ
Θ
Θ
heat generated in the die out the top of the package by lowering the top case temperature. This is done by placing the top
of the package in contact with a copper slug kept at room temperature using a liquid refrigeration unit. Θ
the following formula:
Θ
Θ
Θ
of the package through the leads or balls by lowering the board temperature and insulating the package top. This is done
using a special fixture, which keeps the board in contact with a water chilled copper slug around the perimeter of the package
while insulating the package top. Θ
Θ
Ψ
Ψ
temperature while the part is operating in their system. It is not considered a true thermal resistance. Ψ
the following formula:
Ψ
Table 3-4. Thermal Parameter Values
16
16
Θ
Θ
Θ
Θ
Θ
JA
JA
JA
JA
JMA
JMA
JMA
JC
JC
JC
JB
JB
JB
JT
JT
JT
JA
JMA
JMA
JC
JB
is a number used to express the thermal performance of a part under JEDEC standard natural convection conditions.
is calculated using the following formula:
= (T
is the thermal resistance from junction to board. This number is determined by forcing the heat generated in the die out
= (T
- Junction Temperature to Case Temperature
is the thermal resistance from junction to the top of the case. This number is determined by forcing nearly 100% of the
= (T
correlates the junction temperature to the case temperature. It is generally used by the customer to infer the junction
= (T
- Junction to Air Thermal Resistance
- Junction to Case Thermal Resistance
- Junction to Board Thermal Resistance
is effectively identical to Θ
= (T
- Junction to Moving Air Thermal Resistance
(1 m/s)
(2.5 m/s)
J
J
J
J
– T
J
– T
– T
– T
– T
amb
C
B
C
) / P
) / P
) / P
amb
) / P; where P = power
) / P
Parameter
JA
but represents performance of a part mounted on a JEDEC four layer board inside a wind
JB
JMA
is calculated using the following formula:
is reported at airflows of 200 LFPM and 500 LFPM (linear feet per minute), which
JMA
is calculated using the following formula:
Temperature °C/Watt
25.1
21.4
18.8
13.0
5.8
Data Sheet, Revision 3
September 21, 2005
JC
JT
Agere Systems Inc.
is calculated using
is calculated using