Datasheet

3 3.5 5 6
Input Voltage-V
Iout = 2 A
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
Output Voltage Deviation - %
4 . 5 5.54
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
OutputVoltageDeviation-%
0 0.5 1.5
2
OutputCurrent- A
1
Vin=3.3V
Vin=5V
TPS57112-Q1
SLVSAL8 –DECEMBER 2010 www.ti.com
LOAD REGULATION REGULATION
vs vs
LOAD CURRENT INPUT VOLTAGE
Figure 47. Figure 48.
POWER DISSIPATION ESTIMATE
The following formulas show how to estimate the IC power dissipation under continuous conduction mode (CCM)
operation. The power dissipation of the IC (Ptot) includes conduction loss (Pcon), dead time loss (Pd), switching
loss (Psw), gate drive loss (Pgd) and supply current loss (Pq).
Pcon = Io
2
× R
DS(on)_Temp
Pd = ƒ
sw
× Io × 0.7 × 60 × 10
–9
Psw = 1/2 × V
in
× Io × ƒ
sw
× 8 × 10
–9
Pgd = 2 × V
in
× ƒ
sw
× 2 × 10
–9
Pq = V
in
× 515 × 10
–6
Where:
I
O
is the output current (A).
R
DS(on)_Temp
is the on-resistance of the high-side MOSFET with given temperature (Ω).
V
in
is the input voltage (V).
ƒ
sw
is the switching frequency (Hz).
So
Ptot = Pcon + Pd + Psw + Pgd + Pq
For given T
A
,
T
J
= T
A
+ Rth × Ptot
For given T
J
MAX = 150°C
T
A
MAX = T
J
MAX – Rth × Ptot
Where:
Ptot is the total device power dissipation (W).
T
A
is the ambient temperature (°C).
T
J
is the junction temperature (°C).
Rth is the thermal resistance of the package (°C/W).
T
J
MAX is maximum junction temperature (°C).
T
A
MAX is maximum ambient temperature (°C).
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