RT9728A Datasheet, PDF (11/13 Pages) Richtek Technology Corporation – 120mΩ, 1.3A Power Switch with Programmable Current Limit

single-layer thermal test board. The maximum power
dissipation at T_A = 25°C can be calculated by the following
formula :
P_D(MAX) = (125°C − 25°C) / (250°C/W) = 0.400W for
SOT-23-6 package
P_D(MAX) = (125°C − 25°C) / (165°C/W) = 0.606W for
WDFN-6L 2x2 package
The maximum power dissipation depends on the operating
ambient temperature for fixed T_J(MAX) and thermal
resistance, θ_JA. The derating curves in Figure 2 allow the
designer to see the effect of rising ambient temperature
on the maximum power dissipation.
0.65
0.60
0.55
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
Single-Layer PCB
WDFN-6L 2x2
SOT-23-6
25
50
75
100
125
Ambient Temperature (°C)
Figure 2. Derating Curve of Maximum Power Dissipation
RT9728A
Copyright ©2012 Richtek Technology Corporation. All rights reserved.
DS9728A-03 July 2012
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
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