SI-8050JF
Step-Down
to 5.0 V, 1.5 A,
DC/DC Converter
APPLICATIONS INFORMATION (cont.)
Thermal Protection.
Circuitry turns off the switching
transistor when the junction temperature rises above 150°C.
It is intended only to protect the device from failures due to
excessive junction temperatures and should not imply that
output short circuits or continuous overloads are permitted.
Heat Radiation and Reliability.
The reliability of the
IC is directly related to the junction temperature (T
J
) in its
operation. Accordingly, careful consideration should be
given to heat dissipation. The graph on page 2 illustrates
the effect of thermal resistance on the allowable package
power dissipation.
When mounting to a heat sink, apply silicone grease (Shin-
Etsu Chemical G746, Dow Corning Toray Silicone SC102,
or Toshiba Silicone SY6260). Recommended mounting
hardware torque: 0.588 ~ 0.686 Nm or 6.0 ~ 7.0 kgf•cm
(4.34 ~ 5.06 lbf•ft).
The junction temperature (T
J
) can be determined from
either of the following equations:
T
J
= (P
D
R
θJA
) + T
A
or
T
J
= (P
D
R
θJC
) + T
C
where P
D
= V
I
I
I
– V
O
I
O
– V
F
I
O
(1 – [V
O
/V
I
])
or the adjacent graph,
V
F
= the Schottky diode forward voltage, and
R
θJC
= 6°C/W.
ing rs
tch lato
wi gu
S e
R
Layout Guideline
6
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036
ALLEGRO [ ALLEGRO MICROSYSTEMS ]
