TPS2052C, TPS2062C, TPS2062C-2, TPS2066C, TPS2066C-2

TPS2060C, TPS2064C, TPS2064C-2, TPS2002C, TPS2003C

SLVSAX6H – OCTOBER 2011 – REVISED DECEMBER 2015

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12.3 Power Dissipation and Junction Temperature

It is good design practice to estimate power dissipation and maximum expected junction temperature of the

TPS20xxC and TPS20xxC-2 dual. The system designer can control choices of package, proximity to other power

dissipating devices, and printed circuit board (PCB) design based on these calculations. These have a direct

influence on maximum junction temperature. Other factors such as airflow and maximum ambient temperature

are often determined by system considerations.

Addition of extra PCB copper area around these devices is recommended to reduce the thermal impedance and

maintain the junction temperature as low as practical.

The following procedure requires iteration because power loss is due to the two internal MOSFETs 2 × I2 ×

rDS(on), and rDS(on) is a function of the junction temperature. As an initial estimate, use the rDS(on) at 125°C from the

typical characteristics, and the preferred package thermal resistance for the preferred board construction from

the thermal parameters section.

TJ = TA + [2 × IOUT

2 × r

DS(on) × θJA]

where

•

IOUT = rated OUT pin current (A)

•

rDS(on) = Power switch on-resistance at an assumed TJ (Ω)

•

TA = Maximum ambient temperature (°C)

•

TJ = Maximum junction temperature (°C)

•

θJA = Thermal resistance (°C/W)

(1)

If the calculated TJ is substantially different from the original assumption, look up a new value of rDS(on) and

recalculate.

If the resulting TJ is not less than 125°C, try a PCB construction and/or package with lower θJA.

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Product Folder Links: TPS2052C TPS2062C TPS2062C-2 TPS2066C TPS2066C-2 TPS2060C TPS2064C

TPS2064C-2 TPS2002C TPS2003C