MAX15112EVKIT# Maxim Integrated, MAX15112EVKIT# Datasheet - Page 14

• Manufacturer Part Number: MAX15112EVKIT#
• Description: Power Management IC Development Tools MAX15112 Eval Kit
• Manufacturer: Maxim Integrated
• Type: Power Switchesr
• Series: MAX15112r

Specifications of MAX15112EVKIT#

• Rohs: yes
• Product: Evaluation Kits
• Tool Is For Evaluation Of: MAX15112
• Input Voltage: 2.7 V to 5.5 V
• Output Voltage: 0.6 V
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Output Current: 12 A
• For Use With: MAX15112

The MAX15112 output voltage is adjustable from 0.6V
up to 94% of V
a resistor-divider between the output and GND (see the
Typical Operating
so that the DC errors due to the FB input bias current
(Q500nA) do not affect the output volt age accuracy.
With lower value resistors the DC error is reduced, but
the amount of power consumed in the resistor-divider
increases. R2 values between 1kI and 20kI are accept-
able (see
calculate R1 using:
where the feedback threshold voltage V
When regulating for an output of 0.6V in skip mode, short
FB to OUT and keep R2 connected from FB to GND.
A high-valued inductor results in reduced inductor-ripple
current, leading to a reduced output-ripple voltage.
However, a high-valued inductor results in either a larger
physical size or a high series resistance (DCR) and a
lower saturation current rating. Typically, choose an
inductor value to produce a current ripple, DI
30% of load current. Choose the inductor with the follow-
ing formula:
where f
LIR is the desired inductor current ratio (typically 0.3). In
addition, the peak inductor current, I
be below the 18A high-side current-limit and the inductor
saturation current rating, I
relationship is satisfied:
High-Efficiency, 12A, Current-Mode Synchronous
SW
Step-Down Regulator with Integrated Switches
Table 1
L
is the fixed 1MHz switching frequen cy, and
=
f
IN
R1=R2
SW
Applications Information
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for typical values). Once R2 is chosen,
by connecting FB to the center tap of
Circuits). Choose R1 and R2 values
×
V
LIR I
OUT
Setting the Output Voltage
× 
×

(
L_SAT
V
LOAD
OUT
. Ensure that the following
/V
× 
Inductor Selection
FB


1-
)
-1
V
L_PK
V


OUT
IN
FB
, must always
= 0.6V (typ).



L
, equal to
For a step-down converter, the input capacitor, C
helps to keep the DC input voltage steady, in spite of
discontinuous input AC current. Use low-ESR capacitors
to minimize the voltage ripple due to ESR.
Size C
where DV
voltage across the input capacitors and is recommend-
ed to be less than 2% of the minimum input voltage,
f
output load. The impedance of the input capacitor at
the switching frequency should be less than that of the
input source so high-frequency switching currents do not
pass through the input source, but are instead shunted
through the input capacitor.
Ensure that the input capacitor can accommodate the
input-ripple current require ment imposed by the switch-
ing currents. The RMS input-ripple current is given by:
where I
Use multiple capacitors in parallel to meet the RMS cur-
rent rating requirement.
where:
SW
is the switching frequency (1MHz), and I
IN
RMS
I
RMS
using the following formula:
IN_RIPPLE
I
C
∆
L_PK
is the input RMS ripple current.
=
I
IN
L(P-P)







=
V
=
OUT
f
SW
I
LOAD
=
is the maximum-allowed input-ripple
× ∆
(
×
V
Input Capacitor Selection
I
(
IN
LOAD
V
+
V
IN
V
IN_RIPPLE
−
2
1
IN
V
- V
∆
L x f
OUT
I
L(P-P)
OUT
MAX15112
SW
)
)
x


×
1 2
<
V
V
min (18A, I
V
OUT
V





OUT
IN
IN
×
I
LOAD
LOAD
L_SAT
is the
IN
)
,