General Description
The MAX15015A evaluation kit (EV kit) is a fully assem-
bled and tested PCB that evaluates the MAX15015A
PWM/PFM step-down converter, which integrates a
high-side switch and an LDO regulator. The
MAX15015A EV kit operates over a wide input-
voltage range of 4.5V to 40V and provides up to 1A at
the 3.3V output. The LDO regulator provides up to
50mA at the preset 5V output. The MAX15015A fea-
tures undervoltage lockout, overcurrent, and thermal-
shutdown protection.
The MAX15015A normally operates as a PWM converter
and automatically switches to PFM mode at light loads
to improve efficiency. The MAX15015A switching fre-
quency is preset to 500kHz and features a SYNC input
to provide external frequency synchronization for sensi-
tive applications. The EV kit provides PCB pads to eval-
uate the SYNC and ENABLE features of the
MAX15015A. The EV kit board can also be used to eval-
uate the MAX15015B. The MAX15015A can operate
over the automotive temperature range of -40°C to
+125°C.
Features
o3.3V, 1A, 500kHz Step-Down Converter
o5V, 50mA LDO Regulator
oLDO Voltage Adjustable Up to 11V
oIndependent Turn On/Off Control for Step-Down
Converter (EN_SW)
oRegulator Power-On Reset with Adjustable
Timeout Period
o84% High Efficiency at VIN = 12V and IOUT = 1A
oAutomatic PWM/PFM Mode
oOvercurrent and Thermal-Shutdown Protection
oFully Assembled and Tested
Evaluates: MAX15015A/MAX15015B
MAX15015A Evaluation Kit
________________________________________________________________
Maxim Integrated Products
1
DESIGNATION QTY DESCRIPTION
C1 1
10µF ±10%, 50V X5R ceramic
capacitor (2220)
Murata GRM55DR61H106K
C2, C4, C5, C6,
C15 5
0.1µF ±10%, 50V X7R ceramic
capacitors (0603)
TDK CI608X7R1H104K
C3 1
0.22µF ±10%, 50V X7R ceramic
capacitor (0805)
Murata GRM21BR71H224K
C7 1
47µF ±20%, 6.3V X5R ceramic
capacitor (1206)
TDK C3216X5RUJ476M
C8, C13 2
0.033µF ±10%, 50V X7R ceramic
capacitors (0603)
Murata GRM188R71H333K
C9 1
0.47µF ±10%, 10V X7R ceramic
capacitor (0603)
TDK CI608X7R1A474K
DESIGNATION QTY DESCRIPTION
C10 1
1µF ±10%, 25V X7R ceramic
capacitor (0805)
TDK C2012X7R1E105K
C11 1
10µF ±10%, 16V X7R ceramic
capacitor (1206)
Murata GRM31CR61C106K
C12 1
220pF ±5%, 50V X7R ceramic
capacitor (0603)
TDK C1608X7R1H221J
C14 1
4700pF ±10%, 50V X7R ceramic
capacitor (0603)
Murata GRM188R71H472K
D1 1
150mA, 100V Schotky diode
(SOD-123)
Vishay BAT46W
D2 1 2A, 60V Schotky diode (SMB)
Diode Inc. B260
PART TEMP RANGE IC PACKAGE
MAX15015AEVKIT+ 0°C to +70°C* 36 TQFN-EP**
Ordering Information
Component List
19-0689; Rev 0; 12/06
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
+
Denotes a lead-free and ROHS-complaint EV kit.
*
This limited temperature range is for the EV kit PCB only.
**
EP = Exposed paddle.
Component List continued on next page.
Evaluates: MAX15015A/MAX15015B
Quick Start
Recommended Equipment
• 40V adjustable, 2A power supply
• Electronic load capable of sinking up to 1A
• Three digital voltmeters
Procedure
The MAX15015A EV kit is fully assembled and tested.
Follow these steps to verify board operation. Do not
turn on the power supply until all connections are
completed.
1) Connect the positive terminal of the electronic load
to the VOUT PCB pad on the EV kit board. Connect
the ground terminal of the electronic load to the
PGND PC pad.
2) Connect digital voltmeters across the VIN and
PGND pads, VOUT and PGND PC pads, and the
LDO_OUT and GND pads.
3) Verify that shunts are installed on jumpers JU1 and
JU2 (step-down converter and LDO outputs
enabled).
4) Verify that a shunt is not installed at jumper JU3
(LDO_OUT set to 5V).
5) Connect the power supply’s positive terminal to the
VIN PCB pad on the EV kit. Connect the power-
supply ground terminal to the PGND PC pad.
6) Turn on the power supply.
7) Set the power-supply voltage to 12V.
8) Enable the 1A electronic load.
9) Verify that the voltmeters at VOUT and LDO_OUT
measure 3.3V and 5V, respectively.
Detailed Description
The MAX15015A EV kit evaluates the MAX15015A
PWM/PFM step-down converter with an integrated
high-side switch and LDO regulator. The MAX15015A
EV kit operates over a wide input-voltage range of 4.5V
to 40V and requires a 2A power supply.
The MAX15015A EV kit step-down converter is config-
ured to 3.3V and provides up to 1A (typ). The
MAX15015A step-down converter switching frequency
is set to 500kHz, and can be synchronized to a SYNC
input signal operating below 600kHz. The MAX15015A
normally operates as a PWM converter and automati-
cally switches to PFM mode at light loads to improve
efficiency. The EV kit features PCB pads to evaluate the
SYNC, EN_SW, and the EN_SYS features of the
MAX15015A.
MAX15015A Evaluation Kit
2 _______________________________________________________________________________________2 _______________________________________________________________________________________
DESIGNATION QTY DESCRIPTION
JU1, JU2, JU3 3 2-pin headers
L1 1 27µH, 2.8A inductor
Sumida CDRH124NP-270MC
R1, R2 2 332kΩ ±1% resistors (0603)
R3 0 Not installed, resistor (0603)
R4, R11 2 10kΩ ±5% resistors (0402)
R5 1 1Ω ±5% resistor (0603)
R6 1 2.26kΩ ±1% resistor (0603)
R7 1 4.53kΩ ±1% resistor (0603)
R8 1 133Ω ±1% resistor (0603)
R9 1 7.5kΩ ±1% resistor (0603)
R10 1 61.9kΩ ±1% resistor (0603)
R12 1 63.4kΩ ±1% resistor (0603)
TP1 1 PC mini red test point
U1 1
MAX15015AATX+
(36-pin, 6mm x 6mm x 0.8mm,
TQFN)
— 3 Shunts (JU1, JU2, JU3)
— 1 MAX15015AEVKIT+ PCB
SUPPLIER PHONE WEBSITE
Diodes Inc. 805-446-4800 www.diodes.com
Murata 770-436-1300 www.murata.com
Sumida 847-545-6700 www.sumida.com
TDK 847-803-6100 www.component.tdk.com
Vishay 203-268-6261 www.vishay.com
Component List (continued)
Component Suppliers
Note: Indicate that you are using the MAX15015A when con-
tacting these component suppliers.
The LDO regulator has a default 5V output and can be
configured for a 2.5V output after installing the shunt on
jumper JU3. An open-drain RESET output changes
from low to high whenever the LDO voltage rises to
92.5% of its regulated output. When LDO_OUT
exceeds its rising threshold voltage, RESET remains
low for the reset timeout period, and then goes high.
The RESET signal can be monitored at test point TP1
on the EV kit and is pulled up to LDO_OUT by resistor
R11. The reset timeout period is set by capacitor C8.
The MAX15015A features configurable soft-start, inde-
pendent undervoltage lockout (UVLO) for the step-
down converter and regulator, cycle-by-cycle current
limit, hiccup-mode-output short-circuit protection, and
thermal shutdown. The step-down converter UVLO is
configurable by choosing the appropriate R2 and R3
resistor values.
Jumper Selection
Enabling VOUT and LDO_OUT
The MAX15015A features input pads EN_SW and
EN_SYS that can be used to enable the VOUT and
LDO_OUT outputs. The EV kit also provides jumpers
JU1 and JU2 to configure the EN_SW and EN_SYS,
respectively. See Table 1 for jumpers JU1 and JU2
configurations.
The MAX15015A EV kit shutdown current can be evalu-
ated by removing jumper JU1.
LDO_OUT Selection
Jumper JU3 sets the linear regulator output voltage to
2.5V or 5V. See Table 2 for LDO jumper configuration.
To configure LDO_OUT to other output voltages, refer
to the
Setting the LDO Linear Regulator Output Voltage
section in the MAX15015A data sheet.
Configuring the Output Voltage (VOUT)
The MAX15015A EV kit step-down converter output
voltage is configured to 3.3V by resistors R7 and R9.
The EV kit’s output voltage (VOUT) can be reconfigured
in the range of 1.26V to 28V by replacing these resis-
tors. To select a new value for resistor R7, refer to the
Setting the Output Voltage
section in the MAX15015A
data sheet. Use the following equation to reconfigure
the output voltage to the desired value:
where VOUT is the desired output voltage in volts.
Reconfiguring the MAX15015A EV kit for a new output
voltage may require replacing inductor L1 and capaci-
tors C1 and/or C7. To select a new value for inductor L1
and capacitors C1 and C7, refer to the
Inductor
Selection, Output Capacitor Selection,
and
Input
Capacitor Selection
sections, respectively, in the
MAX15015A data sheet.
Configuring the Undervoltage
Lockout (UVLO)
The MAX15015A step-down converter and LDO regula-
tor turns on when the input voltage (VIN) is above the
MAX15015A minimum 4.1V threshold (shunts on JU1
and JU2 must be installed). The converter turn-on
threshold can be reconfigured to a desired value
greater than 4.1V by selecting resistors R2 and R3. To
reconfigure the converter’s turn-on threshold, use the
following equation:
where VEN_SW is the desired turn-on threshold in volts.
RRx
V
V
EN SW
23 15 1=⎡
⎣
⎢⎤
⎦
⎥
−
_
.
RR
VOUT
79
1 244 1
=⎡
⎣
⎢⎤
⎦
⎥
−
.
Evaluates: MAX15015A/MAX15015B
MAX15015A Evaluation Kit
_______________________________________________________________________________________ 3
Table 1. EN_SYS and EN_SW
Configuration
EV KIT FUNCTION
JU1 SHUNT
POSITION
JU2 SHUNT
POSITION VOUT LDO_OUT
Not installed Not installed Off Off
Not installed Installed Off Off
Installed Not installed Off On
Installed Installed On On
Table 2. LDO Configuration (JU3)
JU3 SHUNT
POSITION
SET_LDO PIN
CONNECTION
LDO_OUT
OUTPUT
VOLTAGE
Not installed Connected to GND 5V
Installed Connects to feedback
resistors R10 and R12 2.5V
Linear Regulator Operation
The MAX15015A linear regulator operates in either a
preset voltage mode or an adjustable mode. In preset
voltage mode, LDO_OUT is 5V. Select the preset volt-
age mode by removing the shunt at JU3. In adjustable
mode, LDO_OUT is set to 2.5V by resistors R10 and
R12 (shunt installed at JU3). To reconfigure LDO_OUT
voltage to a different voltage (1.5V to 11V ), replace
resistors R10 and R12 with new values. Use the follow-
ing equation to select a new resistor value:
where VLDO_OUT is the desired LDO_OUT voltage.
Synchronization Input (SYNC)
The EV kit’s SYNC PCB pad can be used to synchro-
nize the MAX15015A switching frequency with an exter-
nal digital-clock signal in the range of 400kHz to
600kHz. When SYNC is driven with an external digital
clock, the MAX15015A synchronizes to the rising edge
of the external clock.
The square-wave clock source must provide the follow-
ing signal qualities:
• Logic-low = 0 to 0.8V
• Logic-high = 2.2V to 5.5V
• Input frequency = 400kHz to 600kHz. Refer to the
MAX15015A data sheet for more information on the
SYNC pin.
• Duty cycle = 50%
To use external synchronization, connect the external
square-wave clock to the SYNC and GND pads.
Compensation Network
The MAX15015A IC provides the flexibility of externally
compensating its internal error amplifier to achieve
stability for various applications. The MAX15015A is
compensated by choosing values for resistors R6–R9,
and capacitors C12, C13, and C14. To reconfigure the
compensation network for specific requirements, refer
to the
Compensation Design
section in the MAX15015A
data sheet.
Evaluating the MAX15015B
The MAX15015A EV kit board can also evaluate the
MAX15015B step-down converter. The MAX15015A IC
must be removed and replaced with the MAX15015B.
When using the MAX15015B, LDO_OUT has a 3.3V
default output (JU3 not installed).
RR
VLDO OUT
10 12
1 244 1
=⎡
⎣
⎢⎤
⎦
⎥
−
_
.
Evaluates: MAX15015A/MAX15015B
MAX15015A Evaluation Kit
4 _______________________________________________________________________________________
Evaluates: MAX15015A/MAX15015B
_______________________________________________________________________________________ 5
GND
VIN
PGND
JU1
C10
1μF
C8
0.033μF
C11
10μF
C13
0.033μF
C12
220pF
C14
4700pF
C2
0.1μF
SYNC
EN_SW
EN_SYS D1
L1
27μH
C6
0.1μF
R4
10kΩ
R2
332kΩ
1%
R3
OPEN
1
SS DRAIN DRAIN
EN_SYS
EN_SW
N.C.
34 REG
C9
0.47μF
25 DVREG
5SGND
SGND
PGND
29
7
8
33
20 21
IN_SW
36
PGND
22
C-
23
C+
BST
28
15
LX 17
LX 18
CT 6
SYNC
U1
R1
332kΩ
1%
R11
10kΩ
R10
61.9kΩ
1%
R7
4.53kΩ
1%
R12
63.4kΩ
1%
R6
2.26kΩ
1%
R8
133Ω
1%
R9
7.5kΩ
1%
R5
1Ω
MAX15015A
C3
0.22μF
N.C.
2
N.C.
3
N.C.
9
N.C.
12
N.C.
14
N.C.
16
N.C.
19
N.C.
24
N.C.
26
N.C.
27
N.C.
30
N.C. COMP FB
35 31 32
JU2
VIN
VIN
C1
10μF
50V
VOUT
LDO_OUT
VOUT
PGND
GND
C7
47μF
6.3V
VIN
C15
0.1μF
RESET 4
LDO_OUT 11
IN_LDO 13
SET_LDO 10
VOUT
C4
0.1μF
D2
C5
0.1μF
TP1
JU3
MAX15015A Evaluation Kit
_______________________________________________________________________________________ 5
Figure 1. MAX15015A EV Kit Schematic
Evaluates: MAX15015A/MAX15015B
MAX15015A Evaluation Kit
6 _______________________________________________________________________________________
Figure 2. MAX15015A EV Kit Component Placement Guide—
Component Side
Figure 3. MAX15015A EV Kit PCB Layout—Component Side
Figure 4. MAX15015A EV Kit PCB Layout—GND Layer 2 Figure 5. MAX15015A EV Kit PCB Layout—Power Layer 3
Evaluates: MAX15015A/MAX15015B
MAX15015A Evaluation Kit
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________
7
© 2006 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.
Figure 6. MAX15015A EV Kit PCB Layout—Solder Side
