VITESSE
SEMICONDUCTOR CORPORATION
Data Sheet
VSC8061/VSC8062
2.5Gb/s 16-Bit
Multiplexer/Demultiplexer Chipset
The worst-case temperature rise from case to ambient is given by the equation:
where:
∆T = P(MAX)(θSA + θCS)
θSA
=
θCS
=
ΤA(MAX) =
ΤC(MAX) =
∆T
=
P(MAX) =
Theta sink-to-ambient
Theta case-to-sink
Air temperature, user supplied (typically +55o C)
Case temperature (+85oC for Industrial range)
TC - TA
Power (2.0 W for VSC8061)
∴P
=
-∆---T--
Σθ
=
θ----TS---AC-----+-–----θT----CA----S-
θSA = ∆--P---T- – θCS
Ιf TA = 55o C and θCS (user supplied) is typically 0.6o C/W,
θSA = (---8---5----–-2----W5---5---)---°--C--- – 0.6°C ⁄ W
θSA = 14.4°C ⁄ W
Therefore, to maintain the proper case and junction temperature, a heat sink with a θSA of 14.4oC/W or less
must be selected at the appropriate air flow.
NOTE: The heat spreader is tied to VEE in both the VSC8061 and VSC8062.
G52069-0, Rev 4.3
05/11/01
© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012
Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com
Internet: www.vitesse.com
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