MAX17551 5V Output
Evaluation Kit (TDFN)
Evaluates: MAX17551 (TDFN) in
5V Output Voltage Applications
General Description
The MAX17551 5V evaluation kit (EV kit) (TDFN) is a fully
assembled and tested circuit board that demonstrates the
performance of the MAX17551 60V, 50mA ultra-small,
high-efficiency, synchronous step-down DC-DC converter
in a 10-pin TDFN package. The EV kit operates over a
wide input voltage range of 6V to 60V and provides up to
50mA load current at 5V output. It draws only 26µA supply
current under no-load conditions (EN/UVLO connected to
V
IN
). The EV kit is programmed to switch at a frequency
of 300kHz. The device is simple to use and easily con-
figurable with minimal external components. It features
cycle-by-cycle peak current-limit protection, undervoltage
lockout, and thermal shutdown.
The EV kit comes installed with the MAX17551ATB+ in
a 10-pin (3mm x 2mm) lead(Pb)-free/RoHS-compliant
TDFN package.
Quick Start
Recommended Equipment
●
●
●
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MAX17551 5V EV kit (TDFN)
60V adjustable, 0.5A DC power supply
Electronic load up to 50mA
Voltmeter
Procedure
The EV kit is fully assembled and tested. Follow the steps
below to verify board operation.
Caution: Do not turn on
the power supply until all connections are completed.
1)
2)
3)
4)
Verify that shunts are installed on jumpers JU1, JU2
(EN/UVLO).
Verify that jumper JU3 (MODE-PFM operation) is open.
Set the electronic load to constant-current mode,
50mA, and disable the electronic load.
Connect the electronic load’s positive terminal to the
VOUT PCB pad. Connect the negative terminal to
the GND PCB pad.
Connect the voltmeter across the VOUT and GND
PCB pads.
Set the power-supply output to 24V. Disable the
power supply.
Connect the power-supply output to the VIN PCB
pad. Connect the supply ground to the GND PCB
pad.
Turn on the power supply.
Enable the electronic load and verify that output volt-
age is 5V with respect to GND.
Features
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●
●
●
●
●
●
●
●
6V to 60V Input Voltage Range
5V Output, 50mA Continuous Current
26µA No-Load Supply Current
EN/UVLO for On/Off Control and Programmable
Input Undervoltage Lockout
Programmable Switching Frequency
Internal or Programmable Soft-Start
PFM or Forced-PWM Mode of Operation
Open-Drain
RESET
Output
Peak Current-Limit Protection
Thermal Shutdown
Proven PCB Layout
Fully Assembled and Tested
8)
9)
5)
6)
7)
10) Vary the input voltage from 6V to 60V.
11) Vary the load current from 1mA to 50mA and verify
that output voltage is 5V with respect to GND.
Note:
While performing an output short-circuit test, it is
possible for the ceramic output capacitor to oscillate with
the wiring inductance between the capacitor and short-
circuited load, and thereby cause the absolute maximum
rating of the V
OUT
pin (-0.3V) to be exceeded. The
resistor (R7) and the capacitor (C5) are included on this
evaluation kit to protect against unintentional violation of
the above mentioned rating. In the actual system design,
parasitic board or wiring inductance should be minimized
and the output-voltage waveform under short-circuit
operation should be verified to ensure that the absolute
maximum rating of the V
OUT
pin is not exceeded.
Ordering Information
appears at end of data sheet.
19-7597; Rev 0; 4/15
MAX17551 5V Output
Evaluation Kit (TDFN)
Detailed Description
Evaluates: MAX17551 (TDFN) in
5V Output Voltage Applications
RESET
Output
The MAX17551 5V EV kit (TDFN) is a fully assembled and
tested circuit board that demonstrates the performance of
the MAX17551 60V, 50mA ultra-small, high-efficiency, syn-
chronous step-down DC-DC converter in a 10-pin TDFN
package. The EV kit operates over a wide input voltage
range of 6V to 60V and provides up to 50mA load current
at 5V output. It draws only 26µA supply current under no-
load conditions (EN/UVLO connected to VIN). The EV kit
is programmed to switch at a frequency of 300kHz. The
device is simple to use and easily configurable with minimal
external components. It features cycle-by-cycle peak
current-limit protection, undervoltage lockout, and thermal
shutdown.
The EV kit includes an EN/UVLO PCB pad and jumpers
JU1 and JU2 to enable control of the converter output.
The MODE PCB pad and jumper JU3 are provided
for selecting the mode of operation of the converter. A
RESET
PCB pad is available for monitoring the
RESET
output. The RT/SYNC PCB pad can be used to synchro-
nize the EV kit switching frequency to an external clock
frequency.
The EV kit provides a PCB pad to monitor the status of
the
RESET
output.
RESET
goes high when the output
voltage rises above 95% (typ) of its nominal regulated
output voltage.
RESET
goes low when output voltage falls
below 92% (typ) of its nominal regulated voltage.
PFM or Forced-PWM Mode (MODE)
The EV kit includes a jumper (JU3) to select the mode
of operation of the converter. Install a shunt across JU3
before powering up the EV kit to enable the forced-PWM
operation. Keep JU3 open to enable the light-load PFM
operation. See
Table 2
for proper JU3 settings.
Soft-Start
The EV kit offers a fixed 5ms soft-start time. Connect
capacitor C4 to adjust the soft-start time (t
SS
). The
minimum soft-start time is related to the output
capacitance (C
OUT
) and the output voltage (V
OUT
) by the
following equation.
t
SS
> 0.05 x C
OUT
x V
OUT
where t
SS
is in milliseconds and C
OUT
is in µF.
Use the following equation to determine the soft-start
capacitance value (C
SS
):
C
SS
= 6.25 x t
SS
where t
SS
is in milliseconds and C
SS
is in nanofarads.
Enable Control (JU1, JU2)
The EN/UVLO pin on the EV kit serves as an on/off control
while also allowing the user to program the input under-
voltage-lockout (UVLO) threshold. Jumpers JU1 and JU2
configure the EV kit’s output for turn-on/turn-off control.
See
Table 1
for proper JU1, JU2 jumper configurations.
Additionally, resistors R1 and R2 are included to set the
UVLO to a desired turn-on voltage. Refer to the
Setting
the Input Undervoltage-Lockout Level
section in the
MAX17551 IC data sheet for additional information on
setting the UVLO threshold voltage.
External Synchronization (RT/SYNC)
The EV kit provides a PCB pad to synchronize the EV
kit switching frequency to an external clock frequency.
Apply the external clock to the RT/SYNC PCB pad
though an AC-coupling capacitor. Refer to the
External
Synchronization
section in the MAX17551 IC data sheet
for additional information on configuring the external
clock and selecting the AC-coupling capacitor.
Table 1. Enable Control (EN/UVLO) (JU1, JU2)
SHUNT POSITION
JU1
1-2
Open
1-2*
*Default
position.
JU2
Open
1-2
1-2
EN/UVLO PIN
Connected to VIN
Connected to GND
Connected to midpoint of R1, R2 resistor-divider
VOUT OUTPUT
Enabled
Disabled
Enabled at VIN ≥ 6V
Table 2. MODE Control (JU3)
SHUNT POSITION
1-2
Open*
*Default
position.
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│
2
MODE PIN
Connected to GND
Unconnected
MODE OF OPERATION
Forced PWM
PFM
MAX17551 5V Output
Evaluation Kit (TDFN)
EV Kit Performance Report
100
90
80
70
60
50
40
30
20
10
0
1
10
LOAD CURRENT (mA)
PFM MODE
V
IN
= 60V
V
IN
= 24V V
IN
= 36V
V
IN
= 48V
V
IN
= 12V
Evaluates: MAX17551 (TDFN) in
5V Output Voltage Applications
EFFICIENCY vs. LOAD CURRENT
toc1
100.0
90.0
80.0
EFFICIENCY (%)
60.0
50.0
40.0
30.0
20.0
10.0
0.0
0
70.0
EFFICIENCY vs. LOAD CURRENT
toc2
5.08
V
IN
= 12V
OUTPUT VOLTAGE
vs.
LOAD CURRENT
toc3
PFM MODE
V
IN
= 36V
V
IN
= 24V
V
IN
= 48V
V
IN
= 12V
V
IN
= 60V
EFFICIENCY (%)
V
IN
= 24V
V
IN
= 36V
V
IN
= 48V
V
IN
= 60V
OUTPUT VOLTAGE (V)
50
5.05
5.02
4.99
PWM MODE
10
20
30
40
LOAD CURRENT (mA)
4.96
0
10
20
30
40
50
LOAD CURRENT (mA)
4.983
4.981
OUTPUT VOLTAGE
vs. LOAD CURRENT
toc4
LOAD TRANSIENT RESPONSE,
PFM MODE (LOAD CURRENT STEPPED
FROM 2mA to 27mA)
toc5
LOAD TRANSIENT RESPONSE
PFM OR PWM MODE (LOAD CURRENT
STEPPED FROM 25mA TO 50mA)
toc6
PWM MODE
OUTPUT VOLTAGE (V)
4.979
4.977
4.975
4.973
V
IN
= 12V
V
IN
= 24V
V
IN
= 36V
V
IN
= 48V
V
IN
= 60V
V
OUT
(AC)
FIGURE6
APPLICATION
CIRCUIT
V
OUT
=5V
100mV/div
V
OUT
50mV/div
I
OUT
20mA/div
I
OUT
200µs/div
20mA/div
100µs/div
0
10
20
30
40
50
LOAD CURRENT (mA)
LOAD TRANSIENT RESPONSE
PWM MODE (LOAD CURRENT STEPPED
FROM NO LOAD TO 25mA)
toc7
V
EN/UVLO
SOFT-START
toc8
5V/div
BODE PLOT
PHASE
toc9
V
OUT
(AC)
50mV/div
2V/div
GAIN (dB)
V
OUT
20mA/div
f
CR
= 16.3kHz,
PHASE MARGIN = 58°
GAIN
I
OUT
100µs/div
20mA/div
I
OUT
V
RESET
1ms/div
5V/div
FREQUENCY(Hz)
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Maxim Integrated
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3
PHASE (º)
MAX17551 5V Output
Evaluation Kit (TDFN)
Component Suppliers
SUPPLIER
Coilcraft, Inc.
Murata Americas
Panasonic Corp.
Evaluates: MAX17551 (TDFN) in
5V Output Voltage Applications
WEBSITE
www.coilcraft.com
www.murata.com
www.panasonic.com
Note:
Indicate that you are using the MAX17551ATB when contacting these component suppliers.
Component List
Refer to the following files attached to this data sheet for
component information and schematic:
●
MAX17551EV_TDFN_BOM.xls
●
MAX17551EV_TDFN_Schematic.pdf
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Maxim Integrated
│
4
MAX17551 5V Output
Evaluation Kit (TDFN)
Evaluates: MAX17551 (TDFN) in
5V Output Voltage Applications
Figure 1. MAX17551 5V EV Kit (TDFN) Component Placement
Guide—Component Side
Figure 2. MAX17551 5V EV Kit (TDFN) PCB Layout—
Component Side
Figure 3. MAX17551 5V EV Kit (TDFN) PCB Layout—
Solder Side
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Maxim Integrated
│
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