CLP200M_03 Datasheet, PDF (18/21 Pages) STMicroelectronics – OVERVOLTAGE AND OVERCURRENT PROTECTION FOR TELECOM LINE

CLP200M
SUBSTRATES AND MOUNTING INFORMA-
TION
The use of epoxy FR4 boards is quite common for
surface mounting techniques, however, their poor
thermal conduction compromises the otherwise
outstanding thermal performance of the
PowerSO-10. Some methods to overcome this
limitation are discussed below.
One possibility to improve the thermal conduction
is the use of large heat spreader areas at the cop-
per layer of the PC board. This leads to a reduction
of thermal resistance to 35 °C for 6 cm² of the
board heatsink (see fig. 2).
Use of copper-filled through holes on conventional
FR4 techniques will increase the metallization and
decrease thermal resistance accordingly. Using
a configuration with 16 holes under the spreader of
the package with a pitch of 1.8 mm and a diameter
of 0.7 mm, the thermal resistance (junction -
heatsink) can be reduced to 12°C/W (see fig. 3).
Beside the thermal advantage, this solution allows
multi-layer boards to be used. However, a draw-
back of this traditional material prevent its use in
very high power, high current circuits. For in-
stance, it is not advisable to surface mount devices
with currents greater than 10 A on FR4 boards. A
Power Mosfet or Schottky diode in a surface mount
power package can handle up to around 50 A if
better substrates are used.
Fig 2 : Mounting on epoxy FR4 head dissipation by extending the area of the copper layer
ct(s) Copper foil
FR4 board
- ^{Obsolete Produ} _{Fig 3 : Mounting on epoxy FR4 by using copper-filled through holes for heat transfer}
uct(s) _{Copper foil}
FR4 board
Obsolete ^{Prod heatsink}
heat transfer
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