# TPS54040-Q1

Manufacturer Part NumberTPS54040-Q1
DescriptionThe TPS54040 device is a 42-V 0
ManufacturerTexas Instruments
TPS54040-Q1 datasheet

## Specifications of TPS54040-Q1

Iout(max)(a)0.5Vin(min)(v)3.5
Vin(max)(v)42Vout(min)(v)0.8
Vout(max)(v)39Iq(typ)(ma)0.116
Switching Frequency(max)(khz)2500Switch Current Limit(typ)(a)0.6
TopologyBuck,Inverting Buck-BoostOperating Temperature Range(c)-40 to 125
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TPS54040-Q1
SLVSA26C – JANUARY 2010 – REVISED AUGUST 2011
Power Dissipation Estimate
The following formulas show how to estimate the IC power dissipation under continuous conduction mode (CCM)
operation. These equations should not be used if the device is working in discontinuous conduction mode (DCM).
The power dissipation of the IC includes conduction loss (Pcon), switching loss (Psw), gate drive loss (Pgd) and
supply current (Pq).
Vout
2
Pcon = Io
R
´
´
DS(on)
Vin
2
Psw = Vin
sw
lo
0.25
´ ¦
´
´
-
9
Pgd = Vin
3
10
sw
´
´
´ ¦
6
-
Pq = 116
´
10
´
Vin
Where:
IOUT is the output current (A).
R
is the on-resistance of the high-side MOSFET (Ω).
DS(on)
VOUT is the output voltage (V).
VIN is the input voltage (V).
fsw is the switching frequency (Hz).
So
Ptot = Pcon + Psw + Pgd + Pq
For given T
,
A
TJ = TA + Rth
Ptot
´
For given T
= 150°C
JMAX
TAmax = TJmax
Rth
Ptot
-
´
Where:
Ptot is the total device power dissipation (W).
T
is the ambient temperature (°C).
A
T
is the junction temperature (°C).
J
Rth is the thermal resistance of the package (°C/W).
T
is maximum junction temperature (°C).
JMAX
T
is maximum ambient temperature (°C).
AMAX
There will be additional power losses in the regulator circuit due to the inductor ac and dc losses, the catch diode
and trace resistance that will impact the overall efficiency of the regulator.
38
-
9
10
´
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