ADP3050 Analog Devices, ADP3050 Datasheet - Page 17

• Manufacturer Part Number: ADP3050
• Description: 200 kHz, 1 A Step-Down High-Voltage Switching Regulator
• Manufacturer: Analog Devices

For example, a 5 V to 3.3 V system with I
For a total IC power dissipation of
The ADP3050 is offered in a thermally enhanced (not Pb-free)
8-lead SOIC package with a thermal resistance, θ
and in a standard Pb-free 8-lead SOIC package with θ
87.5°C/W.
The maximum die temperature, T
thermal resistance and the maximum ambient temperature
P
(
P
P
P
50
SW
Q
TOTAL
BOOST
×
=
=
10
(
5
⎛
⎜
⎝
×
=
=
0
−
9
10
8 .
P
0
50
×
SW
8 .
×
−
0
3
0
8 .
×
) (
+
6 .
+
×
3
P
5
×
3 .
5
3
BOOST
0 .
3
5
0 .
3 .
2
3 .
0 .
×
=
×
⎞
⎟
⎠
200
35
4
+
+
×
mW
P
10
×
Q
10
−
=
3
J
, is calculated using the
)
410
3
=
)
=
18
357
mW
mW
OUT
mW
= 800 mA
JA
, of 60.6°C/W,
JA
of
(16)
Rev. B | Page 17 of 24
For the previous example (5 V to 3.3 V at 800 mA system, Pb-
free 8-lead SOIC package using good layout techniques) with a
worst-case ambient temperature of 70°C
The maximum operating junction (die) temperature is 125°C,
therefore this system operates within the safe limits of the
ADP3050. Check the die temperature at minimum and
maximum supply voltages to ensure proper operation under all
conditions. Although the PCB and its copper traces provide
sufficient heat sinking, it is important to follow the layout
suggestions in the Board Layout Guidelines section. For any
design that combines high output current with high duty cycle
and/or high input voltage, the junction temperature must be
calculated to ensure normal operation. Always use the
equations in this section to estimate the power dissipation.
T
T
J
J
= 70° C + 87.5° C/W × 0.41 = 105.9° C
=
T
A
+
θ
JA
×
P
TOTAL
ADP3050
(17)