TPS54618-Q1_17 Datasheet, PDF (33/42 Pages) Texas Instruments – 2.95-V to 6-V Input, 6-A Output, 2-MHz, Synchronous Step-Down SWIFT Switcher

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TPS54618-Q1
SLVSBY9D – AUGUST 2013 – REVISED JANUARY 2016
Power Dissipation Estimate (continued)
Pgd = 2 × V_in × ƒ_sw× 10 × 10^–9
where
• V_in is the input voltage (V).
• ƒ_sw is the switching frequency (Hz).
(45)
Pq = V_in × 515 × 10^–6
where
• V_in is the input voltage (V).
(46)
So
Ptot = Pcon + Pd + Psw + Pgd + Pq
where
• Ptot is the total device power dissipation (W).
(47)
For given T_A:
T_J = T_A + Rth × Ptot
where
• T_A is the ambient temperature (°C).
• T_J is the junction temperature (°C).
• Rth is the thermal resistance of the package (°C/W).
(48)
For given T_Jmax = 150°C:
T_Amax = T_Jmax – Rth × Ptot
where
• Ptot is the total device power dissipation (W).
• Rth is the thermal resistance of the package (°C/W).
• T_Jmax is maximum junction temperature (°C).
• T_Amax is maximum ambient temperature (°C).
(49)
There are additional power losses in the regulator circuit due to the inductor AC and DC losses and trace
resistance that impact the overall efficiency of the regulator.
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