eup3408 Eutech Microelectronics Inc, eup3408 Datasheet - Page 9

• Manufacturer Part Number: eup3408
• Description: 1.5mhz, 800ma Synchronous Step-down Converter With Soft Start
• Manufacturer: Eutech Microelectronics Inc

Thermal Considerations
To avoid the EUP3408 from exceeding the maximum
junction temperature, the user will need to do a thermal
analysis. The goal of the thermal analysis is to determine
whether the operating conditions exceed the maximum
junction temperature of the part. The temperature rise is
given by:
Where P
the regulator ; θ
junction of the die to the ambient temperature.
The junction temperature, T
Where T
T
of 125°C.
DS3408 Ver1.2 Nov. 2007
J
should be below the maximum junction temperature
T
T
A
R
D
J
=T
=(P
=I
is the ambient temperature.
LOAD
A
D
+T
)(θ
R
2
JA
JA
× R
)
is the thermal resistance from the
DS(ON)
J
, is given by:
is the power dissipated by
9
PC Board Layout Checklist
When laying out the printed circuit board, the following
guidelines should be used to ensure proper operation of
the EUP3408.
1. The input capacitor C
2. The power traces, consisting of the GND trace, the
3. The V
4. Keep the switching node, SW, away from the
closely as possible. This capacitor provides the AC
current to the internal power MOSFETs.
SW trace and the V
direct and wide.
resistors. The resistive divider R1/R2 must be
connected between the C
sensitive V
FB
pin should connect directly to the feedback
FB
node.
IN
IN
trace should be kept short,
OUT
should connect to V
EUP3408
and ground.
IN
as