Datasheet

TPS54521
www.ti.com SLVS981C –JUNE 2010–REVISED AUGUST 2013
THERMAL INFORMATION
TPS54521
THERMAL METRIC
(1)(2)
QFN UNITS
14 PINS
θ
JA
47.2
θ
JA
Junction-to-ambient thermal resistance
(3)
32
θ
JCtop
Junction-to-case (top) thermal resistance 64.8
θ
JB
Junction-to-board thermal resistance 14.4 °C/W
ψ
JT
Junction-to-top characterization parameter 0.5
ψ
JB
Junction-to-board characterization parameter 14.7
θ
JCbot
Junction-to-case (bottom) thermal resistance 3.2
(1) For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.
(2) Power rating at a specific ambient temperature T
A
should be determined with a junction temperature of 125°C. This is the point where
distortion starts to substantially increase. Thermal management of the PCB should strive to keep the junction temperature at or below
125°C for best performance and long-term reliability. See power dissipation estimate in application section of this data sheet for more
information.
(3) Test board conditions:
(a) 2.5 inches × 2.5 inches, 4 layers, thickness: 0.062 inch
(b) 2 oz. copper traces located on the top of the PCB
(c) 2 oz. copper ground planes on the 2 internal layers and bottom layer
(d) 4 0.010 inch thermal vias located under the device package
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