VITESSE

SEMICONDUCTOR CORPORATION

Data Sheet

VSC7140

1.0625 Gb/s Fibre Channel

Dual Repeater / Hub Node

G52180-0, Rev 4.0

Page 11

10/23/00

©

VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012

Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com

Internet: www.vitesse.com

Package Thermal Characteristics

The VSC7140 is packaged into a thermally-enhanced plastic quad flatpack. This package adheres to the

industry-standard EIAJ footprint for a 10x10mm body but has been enhanced to improve thermal dissipation

with the inclusion of an exposed copper heat spreader. The package construction is as shown in Figure 6.

Figure 6: Package Cross Section

The thermal resistance for the VSC7140 package is improved through low thermal resistance paths from

the die to the exposed surface of the heat spreader and from the die to the leadframe through the heat spreader

overlap of the leadframe.

Table 3: 52 PQFP Thermal Resistance

thermal resistance of the package in still air, the user may operate the VSC7140 in still air if the ambient tem-

is required, an appropriate heatsink must be used with the part or adequate airflow must be provided.

Moisture Sensitivity Level

This device is rated with a moisture sensitivity level 3 rating. Refer to Application Note AN-20 for appro-

priate handling procedures.

Symbol

Description

Value

Units

θ

jc

Thermal resistance from junction to case

2.5

θ

ca

Thermal resistance from case to ambient in still air including conduction through

the leads for a non-thermally saturated board.

37.0

θ

ca-100

Thermal resistance from case to ambient in 100 LFPM air.

31.0

θ

ca-200

Thermal resistance from case to ambient in 200 LFPM air.

28.0

θ

ca-400

Thermal resistance from case to ambient in 400 LFPM air.

24.0

θ

ca-600

Thermal resistance from case to ambient in 600 LFPM air.

22.0

Lead

Copper Heat Spreader

Die

Plastic Molding Compound

Insulator

Wire Bond