AN1703 datasheet(14/22 Pages) STMICROELECTRONICS

Part #	AN1703

Description	GUIDELINES FOR USING ST?셎 MOSFET SMD PACKAGES

PDF	22 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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14 / 22 page

AN1703 - APPLICATION NOTE

14/22

Figure 21 (obtained by measurements performed on PowerFLAT) shows the RTHJ-PCB versus drain pad

area from minimum recommended footprint to 10cm2, for

≤ 10s as power pulse:

Figure 21: RTHJ_PCB versus drain pad area for both types of PowerFLAT™

For the minimum recommended footprint the thermal resistance value is about RTHJ-PCB = 60 °C/W and

the maximum allowable power dissipation results:

For a drain pad area of 1in2 (about 600mm2) we obtain:

In the next figure the maximum allowable power dissipation as function of a PCB drain pad area for

different TJ-TA values is shown:

200

400

600

800

1000

FR-4, 2 oz copper board

Minimum recommended footprint

Area

mm2

PCB

THj

125 =

∆

−

JMAX = 150°C, TC = 25°C)

PCB

THj

125 =

∆

−

JMAX = 150°C, TC = 25°C)

PCB

THJ

PCB

THJ

∆

⇒

−

AN1703 Datasheet(PDF) 14 Page - STMicroelectronics