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FAN5307MPX View Datasheet(PDF) - Fairchild Semiconductor

Part Name
Description
View to exact match
FAN5307MPX
Fairchild
Fairchild Semiconductor Fairchild
FAN5307MPX Datasheet PDF : 13 Pages
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Application Information
Adjustable Output Voltage Version
The output voltage for the adjustable version is set by the
external resistor divider, as shown below:
100k
and is calculated as:
VOUT = 0.5V × 1 + R-R----12-
To reduce noise sensitivity, R1 + R2 should not exceed
1M.
Inductor Selection
The inductor parameters directly related to device perfor-
mances are saturation current and dc resistance. The
FAN5307 operates with a typical inductor value of 10µH.
The lower the dc resistance, the higher the efficiency.
For saturation current, the inductor should be rated
higher than the maximum load current plus half of the
inductor ripple current that is calculated as follows:
IL
=
VOUT
×
-1---------(--V----O----U----T-------V----I--N----)
L×f
where:
f = Switching Frequency
L = Inductor Value
IL = Inductor Ripple Current
Inductor
Value
10µH
6.8µH
10µH
Vendor Part Number
Sumida
Murata
Sumida
Murata
CDRH5D28-100
CDRH5D18-100
CDRH4D28-100
LQH66SN100M01L
CDRH3D16-6R8
CDRH4D18-100
CR32-100
CR43-100
LQH4C100K04
Perfor-
mance
High
Efficiency
Smallest
Solution
Table 1: Recommended Inductors
Input Capacitor Selection
For best performances, a low ESR input capacitor is
required. A ceramic capacitor of at least 4.7µF, placed as
close to the input pin of the device is recommended.
Output Capacitor Selection
The FAN5307’s switching frequency of 1MHz allows the
use of a low ESR ceramic capacitor with a value of 10µF
to 22µF. This provides low output voltage ripple. In power
save mode the output voltage ripple is independent of
the output capacitor value and the ripple is determined
by the internal comparator thresholds. The typical output
voltage ripple at light load is 1% of the nominal output
voltage.
Capacitor
Value
Vendor
Part Number
4.7µF
10µF
22µF
Taiyo Yuden
TDK
Murata
JMK212BY475MG
JMK212BJ106MG
JMK316BJ106KL
C12012X5ROJ106K
C3216X5ROJ106M
GRM32DR60J226K
Table 2: Recommended Capacitors
PCB Layout Recommendations
The inherently high peak currents and switching fre-
quency of the power supplies require a careful PCB lay-
out design. Therefore, use wide traces for the high
current path and place the input capacitor, the inductor,
and the output capacitor as close as possible to the inte-
grated circuit terminals. For the adjustable version the
resistor divider should be routed away from the inductor
to avoid electromagnetic interference.
The 6-lead MLP version of the FAN5307 separates the
high current ground from the reference ground, therefore
it is more tolerant to the PCB layout design and shows
better performance.
9
www.fairchildsemi.com
FAN5307 Rev. 1.0.4
 

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