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MAXM17903 1.5V Output
Evaluation Kit
Evaluates: MAXM17903 1.5V
Output-Voltage Application
General Description
The MAXM17903 1.5V output evaluation kit (EV kit)
provides a proven design to evaluate the MAXM17903
high-voltage, high-efficiency, synchronous step-down
DC-DC module. The EV kit is programmed to deliver
1.5V output for loads up to 300mA. The EV kit features
an adjustable input undervoltage lockout, selectable
mode, and open-drain
RESET
signal. The MAXM17903
data sheet provides a complete description of the module
that should be read in conjunction with this EV kit data
sheet prior to modifying the demo circuit. For full module
features, benefits and parameters, refer to the MAXM17903
data sheet.
Quick Start
Recommended Equipment
● One 4.5V to 21.5V DC, 300mA power supply
● 0.5W resistive load with 300mA sink capacity
● Four digital multimeters (DMM)
● MAXM17903EVKIT#
Equipment Setup and Test 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)
2)
Set the power supply at a voltage between 4.5V and
21.5V. Then, disable the power supply.
Connect the positive terminal of the power supply to
the VIN PCB pad and the negative terminal to the
nearest GND PCB pad. Connect the positive termi-
nal of the 300mA load to the VOUT PCB pad and the
negative terminal to the nearest GND PCB pad.
Connect the DVM (DMM in voltage-measurement
mode) across the VOUT PCB pad and the nearest
GND PCB pad.
Verify that shunt is not installed on jumper J1
(see
Table 1
for details).
Turn on the DC power supply.
Enable the load.
Verify that the DVM displays 1.5V.
Features
● Highly Integrated Solution
● Wide 4.5V to 21.5V Input Range
●
Programmed 1.5V Output, Delivers Up To 300mA
Output Current
● High 75.50%% Efficiency
(V
IN
= 12V, V
OUT
= 1.5V at 100mA)
● 500kHz Switching Frequency
● ENABLE/UVLO Input, Resistor-Programmable UVLO
Threshold
● PFM Feature for Better Light-Load Efficiency
● Fixed Internal 4.1ms Soft-Start Time
● RESET Output, with Pullup Resistor to V
CC
● Overcurrent and Overtemperature Protection
(OCP and OTP)
● Low-Profile, Surface-Mount Components
● Proven PCB Layout
● Fully Assembled and Tested
3)
4)
5)
6)
7)
Ordering Information
appears at end of data sheet.
319-100149; Rev 0; 2/18
MAXM17903 1.5V Output
Evaluation Kit
Detailed Description
Evaluates: MAXM17903 1.5V
Output-Voltage Application
For MAXM17903 to turn on at 4.5V input, the Resistor R2
is calculated to be 825kΩ.
The MAXM17903 EV kit is designed to demonstrate
salient features of MAXM17903 power module. The EV kit
includes an EN/UVLO PCB pad, and jumper J1, to enable
the output at a desired input voltage. Jumper J2 allows
selection of either PWM or PFM mode of operation based
on light-load performance requirements. An additional
RESET
pad is available for monitoring if the converter
output voltage is in regulation.
Input Capacitor Selection
Output Capacitor Selection
The input capacitor serves to reduce the current peaks
drawn from the input power supply and reduces switching
frequency ripple at the input. The input capacitance must
be greater than or equal to the value given in Table 1 of
MAXM17903
data sheet. Input capacitor C3 is chosen to
be 1µF/25V.
X7R ceramic output capacitors are preferred due to their
stability over temperature in industrial applications. The
required output capacitor (C5) for 1.5V output is selected
from Table 1 of the
MAXM17903
data sheet as 22µF/6.3V.
Hot-Plug-In and Long Input Cables
Adjusting Output Voltage
The MAXM17903 supports an adjustable output-voltage
range, from 0.9V to 5V, using a feedback resistive divider
from V
OUT
to FB. Output voltage can be programmed
using the values given in Table 1 of the
MAXM17903
data
sheet. For 1.5V output, R3 is chosen as 49.9kΩ, and R4
is chosen as 75kΩ.
Enable/Undervoltage-Lockout (EN/UVLO)
Programming
The MAXM17903 offers an adjustable input undervoltage-
lockout feature. In this EV kit, for normal operation, leave
jumper J1 open. When J1 is left open, the MAXM17903
is enabled when the input voltage rises above 4.5V. To
disable MAXM17903, install a jumper across pins 2-3 on
J1. See
Table 1
for J1 settings. A potential divider formed
by R1 and R2 sets the input voltage (V
INU
) at which the
module is enabled. The value of resistor R1 is chosen
to be 2.2MΩ, and R2 is calculated using the following
equation:
R
2
=
( V
INU
−
1.215 )
R
1
×
1.215
The MAXM17903 EV kit PCB provides an optional
electrolytic capacitor (C2, 4.7µF/50V) to dampen input
voltage peaks and oscillations that can arise during hot-
plug-in and/or due to long input cables. This capacitor
limits the peak voltage at the input of the MAXM17903
power module, when the EV kit is powered directly from a
precharged capacitive source or an industrial backplane
PCB. Long input cables, between input power source and
the EV kit circuit can cause input-voltage oscillations due
to the inductance of the cables. The equivalent series
resistance (ESR) of the electrolytic capacitor helps damp
out the oscillations caused by long input cables. Further,
capacitor C1 (0.1µF/50V), placed near the input of the
board, helps in attenuating high frequency noise.
Mode of Operation
The MAXM17903 features PFM mode of operation to
increase the efficiency at light-load condition. If the MODE
pin is left unconnected during powerup, the module
operates in PFM mode at light loads. If the MODE pin is
connected to GND during power-up, the part operates in
constant-frequency PWM mode at all loads. See
Table 2
for J2 settings.
Internal LDO
where R1 and R2 are in kΩ,
An internal regulator provides a 5V nominal supply to
power the internal functions of the module. The output of
the linear regulator (V
CC
) should be bypassed with a 1µF
capacitor C4 to GND.
Table 1. UVLO Enable/Disable Configuration (J1)
POSITION
Not Installed*
1-2
2-3
*Default position
EN/UVLO PIN
Connected to the center node of resistor-divider
R1 and R2.
Connected to V
IN
Connected to GND
MAXM17903_ OUTPUT
Programmed to startup at desired input-voltage
level.
Enabled if V
IN
is greater than V
IN(MIN).
Disabled
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Maxim Integrated │
2
MAXM17903 1.5V Output
Evaluation Kit
Table 2. Mode of Operation (J2)
POSITION
1-2
Not Installed*
*Default position
Operates in PWM mode.
Evaluates: MAXM17903 1.5V
Output-Voltage Application
MODE PIN
Operates in PFM mode at light-load conditions.
EV Kit Performance Report
STARTUP THROUGH ENABLE
(V
IN
= 12V, V
OUT
= 1.5V, PWM MODE, FULL LOAD)
toc01
100
5V/div
EFFICIENCY
vs.
LOAD CURRENT
(V
OUT
= 1.5V, PWM MODE)
toc02
90
80
EFFICIENCY
(%)
70
60
50
40
30
20
10
0
V
IN
= 5V
V
IN
=
12V
V
IN
=
20V
EN/UVLO
LX
10V/div
1V/div
5V/di
v
V
OUT
RESET
1ms/div
0
30 60 90 120 150
180
210 240 270 300
LOAD CURRENT
(mA)
100
90
80
EFFICIENCY
vs.
LOAD CURRENT
(V
OUT
= 1.5V, PFM MODE)
toc03
OUTPUT VOLTAGE
vs.
LOAD CURRENT
(V
OUT
= 1.5V, PWM MODE)
toc04
1.508
1.504
OUTPUT VOLTAGE
(V)
1.500
1.496
1.492
1.488
1.484
V
IN
=
20V
V
IN
= 5V
EFFICIENCY
(%)
70
60
50
40
30
20
10
0
1
10
100
V
IN
= 5V
V
IN
=
12V
V
IN
=
20V
V
IN
=
12V
0
30 60 90 120 150
180
210 240 270 300
LOAD CURRENT
(mA)
LOAD CURRENT
(mA)
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Maxim Integrated │
3
MAXM17903 1.5V Output
Evaluation Kit
EV Kit Performance Report (continued)
OUTPUT VOLTAGE
vs.
LOAD CURRENT
(V
OUT
= 1.5V, PFM MODE)
toc05
Evaluates: MAXM17903 1.5V
Output-Voltage Application
1.55
1.54
OUTPUT VOLTAGE
(V)
1.53
1.52
1.51
1.50
1.49
1.48
1.510
OUTPUT VOLTAGE
vs.
INPUT VOLTAGE
(V
OUT
= 1.5V, PWM MODE)
toc06
V
IN
= 5V
OUTPUT VOLTAGE
(V)
V
IN
=
20V
V
IN
=
12V
1.505
I
OUT
= 0A
I
OUT
= 200mA
I
OUT
= 300mA
1.500
I
OUT
= 100mA
1.495
0
30 60 90 120 150
180
210 240 270 300
LOAD CURRENT
(mA)
1.490
0
5
10
15
20
25
INPUT VOLTAGE(V)
(V
IN
OUTPUT-VOLTAGE
RIPPLE
= 12V, V
OUT
= 1.5V FULL LOAD, PWM MODE)
toc07
LOAD TRANSIENT RESPONSE
(V
IN
= 12V, V
OUT
= 1.5V, PFM MODE)
(LOAD CURRENT STEPPED FROM 5mA
to 150
m
A)
toc08
V
OUT
(AC)
20mV/di
v
10mV/di
v
V
OUT
(AC)
I
OUT
2µs/div
100µs/div
100mA/d
iv
LOAD TRANSIENT RESPONSE
(V
IN
= 12V, V
OUT
= 1.5V, MODE = PWM)
(LOAD CURRENT STEPPED FROM 150mA
TO 300mA)
toc09
BODE PLOT
(V
IN
= 12V, V
OUT
= 1.5V, PWM MODE, FULL LOAD)
80
60
toc10
90
60
GAIN (dB)
20
0
-20
-40
-60
-80
1k
GAIN
0
-30
CROSSOVER FREQUENCY = 59.55kHz
PHASE MARGIN = 51.03°
10k
FREQUENCY (Hz)
-60
100mA/div
I
OUT
100µs/div
-90
100k
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Maxim Integrated │
4
PHASE MARGIN (°)
V
OUT
(AC)
20mV/div
40
PHAS
E
30
MAXM17903 1.5V Output
Evaluation Kit
Ordering Information
PART
MAXM17903EVKIT#
#Denotes RoHS compliant.
TYPE
EV Kit
Evaluates: MAXM17903 1.5V
Output-Voltage Application
Component Suppliers
SUPPLIER
Murata Americas
NEC TOKIN America, Inc.
Panasonic Corp.
SANYO Electric Co., Ltd.
TDK Corp.
TOKO America, Inc.
WEBSITE
www.murata.com
www.nec-tokinamerica.com
www.panasonic.com
www.sanyodevice.com
www.component.tdk.com
www.tokoam.com
Note:
Indicate that you are using the MAXM17903 when
contacting these component suppliers.
MAXM17903 1.5V EV Kit Bill of Materials
ITEM QTY DESIGNATION
1
2
3
4
5
6
7
8
9
10
11
12
1
1
1
1
1
1
1
1
1
1
1
1
C1
C2
C3
C4
C5
C6
R1
R2
R3
R4
R5
U1
DESCRIPTION
0.1µF±10%,50V, X7R ceramic capacitor (0603)
4.7µF±20%,50V, Aluminimum Capacitor
1µF±10%,25V, X7R ceramic capacitor (0805)
1µF±10%,16V, X7R ceramic capacitor (0603)
22µF±10%,6.3V, X7R ceramic capacitor (1206)
OPEN
2.2MΩ ±1% resistor (0402)
825kΩ ±1% resistor (0402)
49.9kΩ ±1% resistor (0402)
75kΩ ±1% resistor (0402)
100kΩ ±1% resistor (0402)
MAXM17903, 10-pin micro-SLIC Power Module
Manufacturer Partnumber-1
SAMSUNG ELECTRONICS
CL10B104KB8NFN
NICHICON UUD1H4R7MCL
MURATA GRM219R71E105K
MURATA GRM188R71C105KA12
MURATA GRM31CR70J226K
N/A
VISHAY DALE CRCW04022M20FK
VISHAY DALE CRCW0402825KFK
VISHAY DALE CRCW040249K9FK
VISHAY DALE CRCW040275K0FK
VISHAY DALE CRCW0402100KFK
MAXIM MAXM17903AMB+T
YAGEO RC0402FR-07100KL
TDK C1608X7R1C105K
Manufacturer Partnumber-2
www.maximintegrated.com
Maxim Integrated │
5
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