MAX15112 Evaluation Kit
Evaluates: MAX15112
General Description
The MAX15112 evaluation kit (EV kit) provides a prov-
en design to evaluate the MAX15112 high-efficiency,
12A, step-down regulator with integrated switches in
a 24-bump wafer-level package (WLP). The EV kit is
preset for 1.5V output at load currents up to 12A from a
2.7V to 5.5V input supply. The device features a 1MHz
fixed switching frequency, which allows the EV kit to
achieve an all-ceramic capacitor design and fast tran-
sient responses.
S
All-Ceramic Capacitor Design
S
1MHz Switching Frequency
S
Output Voltage Range
0.6V Up to 0.94 x V
IN
(Forced PWM)
0.6V Up to 0.85 x V
IN
(Skip Mode)
S
Enable Input/Power-Good Output
S
Selectable Skip-Mode Functionality
S
Proven PCB Layout
S
Fully Assembled and Tested
Ordering Information
appears at end of data sheet.
Features
S
Operates from a 2.7V to 5.5V Input Supply
Component List
DESIGNATION
C1, C2, C3
QTY
3
DESCRIPTION
22FF
Q20%,
6.3V X5R ceramic
capacitors (1206)
TDK C3216X5R0J226M
Not installed, ceramic capacitor
(0603)
100FF
Q10%,
6.3V X5R ceramic
capacitors (1206)
Murata GRM31CR60J107M
Not installed, ceramic capacitors
(1206)
1FF
Q10%,
10V X7R ceramic
capacitor (0603)
Murata GRM188R71A105K
0.47FF
Q10%,
16V X7R ceramic
capacitor (0603)
Murata GRM188R71C474K
22pF
Q5%,
50V ceramic
capacitor (0603)
Murata GRM1885C1H220J
3300pF
Q10%,
50V X7R ceramic
capacitor (0603)
Murata GRM188R71H332K
C18
1
DESIGNATION
QTY
DESCRIPTION
0.1FF
Q10%,
50V X7R ceramic
capacitor (0603)
TDK C1608X7R1H104K
Murata GRM188R71H104K
1500pF
Q10%,
50V X7R ceramic
capacitor (0603)
Murata GRM188R71H152K
10FF
Q10%,
6.3V X5R ceramic
capacitors (0603)
Murata GRM188R60J106K
1000FF
Q20%,
10V aluminum
electrolytic capacitors (10.3mm x
10.3mm)
Panasonic EEEFP1A102AP
2.2FF
Q10%,
16V X7R ceramic
capacitor (0603)
Murata GRM188R61C225K
TDK C1608X5R1C225K
Binding posts
2-pin header
3-pin header
0.22FH, 21A inductor
Vishay IHLP2525BD01R22M01
C16
1
C5
0
C7, C8
2
C9, C10
0
C19, C20
2
C11
1
C21, C22
2
C13
1
C23
1
C14
1
IN, OUT,
PGND (x2)
JU1
JU2
L1
4
1
1
1
C15
1
For pricing, delivery, and ordering information, please contact Maxim Direct at
1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
19-5992; Rev 1; 9/12
MAX15112 Evaluation Kit
Evaluates: MAX15112
Component List (continued)
DESIGNATION
R1
R2
R3
R4, R5
R6
R7
R8
R12
QTY
1
1
1
2
1
1
1
1
DESCRIPTION
3.32kI
Q1%
resistor (0603)
2.21kI
Q1%
resistor (0603)
5.23kI
Q1%
resistor (0603)
100kI
Q5%
resistors (0603)
100I
Q5%
resistor (0603)
4.7I
Q5%
resistor (0603)
1I
Q1%
resistor (0805)
10I
Q1%
resistor (0603)
—
—
2
1
U1
1
DESIGNATION
R13
R14
QTY
1
1
DESCRIPTION
0I
Q5%
resistor (0603)
470I
Q5%
resistor (0402)
12A current-mode buck converter
(24 WLP)
Maxim MAX15112EWG+
Shunts
PCB: MAX15112 EVALUATION
KIT
Component Suppliers
SUPPLIER
Murata Electronics North America, Inc.
TDK Corp.
Vishay
PHONE
770-436-1300
847-803-6100
402-563-6866
WEBSITE
www.murata-northamerica.com
www.component.tdk.com
www.vishay.com
Note:
Indicate that you are using the MAX15112 when contacting these component suppliers.
Quick Start
•
MAX15112 EV kit
Detailed Description of Hardware
The MAX15112 EV kit provides a proven design to
evaluate the MAX15112 high-efficiency, 12A, step-down
regulator with integrated switches. The applications
include distributed power systems, portable devices,
and preregulators. The EV kit is preset for 1.5V output at
load currents up to 12A from a 2.7V to 5.5V input supply.
The device features a 1MHz fixed switching frequency,
which allows the EV kit to achieve an all-ceramic capaci-
tor design and fast transient responses. Input aluminum
electrolytic capacitors (C21, C22) are provided to damp
the input if long wires are used; they are not required in
a tight system design.
Soft-Start and Reference Input (SS/REFIN)
The device utilizes an adjustable soft-start function to
limit inrush current during startup. The soft-start time is
adjusted by the value of C16, the external capacitor from
SS/REFIN to GND. By default, C16 is currently 0.1FF,
which gives a soft-start time of approximately 6ms.
To adjust the soft-start time, determine C16 using the
following formula:
C16 = (10FA x t
SS
)/0.6V
where t
SS
is the required soft-start time in seconds
and C16 is in farads. C16 should be a minimum of 1nF
capacitor between SS/REFIN and GND. The resistor in
series with the soft-start capacitor (R14) improves load
regulation.
Recommended Equipment
•
5V, 7A DC power supply
•
Load capable of sinking 12A
•
Digital voltmeter
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 PCB pad and the negative terminal to the nearest
PGND PCB pad.
2) Connect the positive terminal of the 12A load to
the OUT PCB pad and the negative terminal to the
nearest PGND PCB pad.
3) Connect the digital voltmeter across the OUT PCB
pad and the nearest PGND PCB pad.
4) Verify that a shunt is installed on jumper JU1.
5) Verify that a shunt is installed on 2-3 on jumper JU2.
6) Turn on the DC power supply.
7) Enable the load.
8) Verify that the voltmeter displays 1.5V.
Procedure
Maxim Integrated
2
MAX15112 Evaluation Kit
Evaluates: MAX15112
When no external reference is applied at SS/REFIN, the
device uses the internal 0.6V reference. An external
tracking reference with steady-state value between 0
and V
IN
- 2.5V can be applied to SS/REFIN. Refer to the
Setting the Soft-Start Time
section of the MAX15112 IC
data sheet for a more detailed description. During 1ms
hiccup timeout, the SS/REFIN pin is pulled to GND inter-
nally to discharge the soft-start capacitor. R6 limits the
currents from an externally supplied reference during the
1ms hiccup timeout event.
The EV kit can be adjusted from 0.6V up to 0.94 x V
IN
(forced PWM) by changing the values of resistors R1 and
R2. To determine the value of the resistor-divider, first
select R2 between 1kI and 20kI. Then use the following
equation to calculate R1:
R1 = R2 [(V
OUT
/V
FB
) - 1]
where V
FB
is equal to the reference voltage at SS/REFIN
and V
OUT
is the desired output. If no external reference is
applied at SS/REFIN the internal reference is automatically
selected and V
FB
becomes 0.6V. When regulating for an
output of 0.6V in skip mode, set R1 to 0I and keep R2
connected from FB to GND.
When R1 is changed, compensation components C14,
R1, and C15 must be changed to ensure loop stability
(refer to the
Compensation Design Guidelines
section in
the MAX15112 IC data sheet).
The device features a regulator enable input. For normal
operation, a shunt should be installed on jumper JU1.
To disable the output, remove the shunt on JU1 and the
EN pin will be pulled to PGND through resistor R4. See
Table 1 for JU1 settings.
The device offers selectable skip-mode functionality
to reduce current consumption and achieve a higher
efficiency at light loads. To operate in skip mode, install
a shunt on pins 1-2 on jumper JU2. See Table 2 for JU2
settings.
Caution: Do not change the setting of the
skip jumper while the device is operating.
Regulator Enable (EN)
Setting the Output Voltage
Skip-Mode Input (SKIP)
Table 1. Regulator Enable (EN) Jumper JU1 Description
SHUNT POSITION
Installed*
Not installed
*Default
position.
EN PIN
Connected to IN
Pulled to PGND through R4
DEVICE OUTPUT
Enabled
Disabled
Table 2. Skip-Mode Input (SKIP) Jumper JU2 Description
SHUNT POSITION
1-2
2-3*
*Default
position.
SKIP PIN
Connected to EN
Connected to PGND
MODE
Skip-mode operation
Forced-PWM operation
Maxim Integrated
3
IN
JU1
D5
EN
BST
A4
Maxim Integrated
R7
4.7
R4
100k
1
2
3
L1
0.22uH
C18
1500pF
C5
SKIP
EN
JU2
C13
0.47uF
R8
1
1%
SKIP
PGOOD
A5
PGOOD
LX
LX
LX
LX
LX
LX
A3
A2
C3
C2
B3
B2
OUT
Figure 1. MAX15112 EV Kit Schematic
R12
D3
AIN
U1
MAX15112
GND
GND
GND
GND
GND
*V1
S
C7
100uF
C8
100uF
C10
OPEN
C9
OPEN
C20
10uF
OUT
IN
R5
100k
10
C23
2.2uF
GSNS
A6
IN
D2
D1
A1
C1
B1
IN
B4
IN
D4
IN
C4
IN
C21
1000uF
C22
1000uF
PGND
+
C3
22uF
C11
1uF
R
B5
N.C.
+
C2
22uF
C1
22uF
C19
10uF
PGND
*V2
PGND
PGND
R
C6
SS/REFIN
FB
B6
SS/REFIN
D6
COMP
R6
R14
470
R3
5.23k
1%
C16
0.1uF
R2
2.21k
1%
R
R1
3.32k
1%
100
C5
OPEN
S
C15
3300pF
C14
22pF
SGND
R13
0
POWER GND (PGND)
TOP LAYER GND FLOOD, SYSTEM GND
S
S
SMALL SIGNAL GND (SGND)
20 MIL TRACE ON THE BOTTOM THAT
TIES TO PGND ONLY ON COMPONENT LAYER AT VIA NEXT TO U1
R
REMOTE SENSE GND (RGND)
TRACE TO REMOTE SENSE THE GND VOLTAGE AT THE LOAD.
TIES TO PGND ONLY AT THE LOAD
* VIA "*V1" ONLY AT U1 MUST ONLY CONNECT TO U1 SIDE GND, (NOT L2,L3,BOTTOM LAYER)
* VIA "*V2" MUST NOT CONNECT TO THE GND PLANES, RGND ONLY CONNECTS TO THE PGND AT THE LOAD
REQUEST THICKEST COPPER POSSIBLE ON THE TOP LAYER
MAX15112 Evaluation Kit
Evaluates: MAX15112
4
MAX15112 Evaluation Kit
Evaluates: MAX15112
1.0’’
1.0’’
Figure 2. MAX15112 EV Kit Component Placement Guide—
Component Side
Figure 4. MAX15112 EV Kit PCB Layout—Inner Layer 2
1.0’’
1.0’’
Figure 3. MAX15112 EV Kit PCB Layout—Component Side
Maxim Integrated
Figure 5. MAX15112 EV Kit PCB Layout—Inner Layer 3
5
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