Datasheet

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MaximIntegrated │ 17
MAX15062 60V, 300mA, Ultra-Small, High-Efciency,
Synchronous Step-Down DC-DC Converters
Input Capacitor
Small ceramic capacitors are recommended for the
device. The input capacitor reduces peak current drawn
from the power source and reduces noise and voltage
ripple on the input caused by the switching circuitry. A
minimumof1µF,X7R-gradecapacitorinapackagelarger
than 0805 is recommended for the input capacitor of the
device to keep the input voltage ripple under 2% of the
minimum input voltage, and to meet the maximum ripple-
current requirements.
Output Capacitor
Small ceramic X7R-grade capacitors are sufficient and
recommended for the device. The output capacitor has
twofunctions.Itfiltersthesquarewavegeneratedbythe
devicealongwiththeoutputinductor.Itstoressufficient
energy to support the output voltage under load transient
conditionsandstabilizesthedevice’sinternalcontrolloop.
Usually the output capacitor is sized to support a step
load of 50% of the maximum output current in the appli-
cation, such that the output-voltage deviation is less than
3%. The device requires a minimum of 10µF capacitance
for stability. Required output capacitance can be calcu-
lated from the following equation:
OUT
OUT
30
C
V
=
where C
OUT
is the output capacitance in µF and V
OUT
is the output voltage. See Table 2 to select the output
capacitor for typical applications.
Setting the Input Undervoltage-Lockout Level
The devices offer an adjustable input undervoltage-
lockout level. Set the voltage at which the device turns
on with a resistive voltage-divider connected from V
IN
toGND(seeFigure 1). Connect the center node of the
divider to EN/UVLO.
ChooseR1tobe3.3MΩmax,andthencalculateR2as
follows:
INU
R1 1.215
R2
(V - 1.215)
×
=
where V
INU
is the voltage at which the device is required
to turn on.
Table 2. Output Capacitor Selection
Figure 1. Adjustable EN/UVLO Network
Table 1. Inductor Selection
INPUT VOLTAGE
RANGE V
IN
(V)
V
OUT
(V) I
OUT
(mA) C
OUT
(µF) RECOMMENDED PART NO.
4.5 to 60 3.3 (Fixed) 300 10µF/1206/X7R/6.3V
MurataGRM31CR70J106K
6 to 60 5 (Fixed) 300 10µF/1206/X7R/6.3V MurataGRM31CR70J106K
4.5 to 60 1.8 or 2.5 300 22µF/1206/X7R/6.3V MurataGRM31CR70J226K
14 to 60 12 300 4.7µF/1206/X7R/16V MurataGRM31CR71C475K
17 to 60 15 300 4.7µF/1206/X7R/25V MurataGRM31CR71E475K
INPUT VOLTAGE
RANGE V
IN
(V)
V
OUT
(V) I
OUT
(mA) L (µH) RECOMMENDED PART NO.
4.5 to 60 3.3 (Fixed) 300 33 Coilcraft LPS4018-333ML
6 to 60 5 (Fixed) 300 47 Coilcraft LPS4018-473ML
4.5 to 60 1.8 or 2.5 300 22 Coilcraft LPS4018-223ML
14 to 60 12 300 100 Wurth 74408943101
17 to 60 15 300 150 TDK VLC6045T-151M
R2
R1
EN/UVLO
MAX15062
V
IN
V
IN