Datasheet

MAX15053 Evaluation Kit
Evaluates: MAX15053
2 ______________________________________________________________________________________
Quick Start
Recommended Equipment
• MAX15053 EV kit
• 5V, 2A DC power supply
• Load capable of 2A
• Digital voltmeter
Procedure
The EV kit is fully assembled and tested. Follow
the steps below to verify the board operation.
Caution: Do not turn on power supply until all
connections are completed.
1) Connect the positive terminal of the 5V supply to the
IN pad and the negative terminal to the nearest PGND
pad.
2) Connect the positive terminal of the 2A load to the
OUT pad and the negative terminal to the nearest
PGND pad.
3) Connect the digital voltmeter across the OUT pad
and the nearest PGND pad.
4) Verify that a shunt is installed on pins 1-2 of jumper
JU1.
5) Verify that a shunt is installed on pins 2-3 of jumper
JU3.
6) Turn on the DC power supply.
7) Enable the load.
8) Verify that the voltmeter displays 1.8V.
Detailed Description of Hardware
The MAX15053 EV kit provides a proven design to
evaluate the MAX15053 high-efficiency, 2A, step-down
regulator with integrated switches. The applications
include distributed power systems, portable devices,
and preregulators. The EV kit is preset for 1.8V out-
put at load currents up to 2A from a 2.7V to 5.5V
input supply. The IC features a 1MHz fixed switching
frequency, which allows the EV kit to achieve an all-
ceramic capacitor design and fast transient responses.
Reference Input and Soft-Start (SS/REFIN)
The MAX15053 utilizes an adjustable soft-start function
to limit inrush current during startup. The soft-start time is
adjusted by the value of C4, the external capacitor from
SS/REFIN to GND. By default, C4 is currently 22000pF,
which gives a soft-start time of approximately 1.3ms. To
adjust the soft-start time, determine C4 using the follow-
ing formula:
C4 = (10FA x t
SS
)/0.6V
where t
SS
is the required soft-start time in seconds and
C4 is in farads. C4 should be a minimum 1nF capacitor
between SS/REFIN and GND.
When no external reference is applied at SS/REFIN,
the device uses the internal 0.6V reference. When an
external reference is used, soft-start needs to be pro-
vided externally.
Setting the Output Voltage
The EV kit can be adjusted from 0.6V up to 0.94 x V
IN
by changing the values of resistors R1 and R2. To
determine the value of the resistor-divider, first select R1
between 2kI and 10kI and then use the following equa-
tion to calculate R2:
R2 = (V
FB
x R1)/(V
OUT
- V
FB
)
where V
FB
is equal to the reference voltage at
SS/REFIN and V
OUT
is the output. If no external refer-
ence is applied at SS/REFIN, the internal reference is
automatically selected and V
FB
becomes 0.6V. In this
case, R2 is not needed for V
OUT
= 0.6V.
When R2 is changed, compensation components
must be recalculated to ensure loop stability (refer to
the Compensation Design Guidelines section in the
MAX15053 IC data sheet).
Regulator Enable (EN)
The IC features an enable input. For normal operation, a
shunt should be installed on pins 1-2 of jumper JU1. To
disable the output, install a shunt on pins 2-3 of JU1. See
Table 1 for JU1 shunt positions.
Note: Indicate that you are using the MAX15053 when contacting these component suppliers.
Component Suppliers
SUPPLIER PHONE WEBSITE
Murata Electronics North America, Inc. 770-436-1300 www.murata-northamerica.com
TDK Corp. 847-803-6100 www.component.tdk.com
Vishay 402-563-6866 www.vishay.com