in 5V Output Voltage Applications MAX17551 5V

in 5V Output Voltage Applications MAX17551 5V
Evaluates: MAX17551 (TDFN) in
5V Output Voltage Applications
MAX17551 5V Output
Evaluation Kit (TDFN)
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
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.
Quick Start
Recommended Equipment
●●
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) Verify that shunts are installed on jumpers JU1, JU2
(EN/UVLO).
The EV kit comes installed with the MAX17551ATB+ in
a 10-pin (3mm x 2mm) lead(Pb)-free/RoHS-compliant
TDFN package.
2) Verify that jumper JU3 (MODE-PFM operation) is open.
Features
4) Connect the electronic load’s positive terminal to the
VOUT PCB pad. Connect the negative terminal to
the GND PCB pad.
3) Set the electronic load to constant-current mode,
50mA, and disable the electronic load.
●●
6V to 60V Input Voltage Range
●●
5V Output, 50mA Continuous Current
●●
26µA No-Load Supply Current
5) Connect the voltmeter across the VOUT and GND
PCB pads.
●●
EN/UVLO for On/Off Control and Programmable
Input Undervoltage Lockout
6) Set the power-supply output to 24V. Disable the
power supply.
●●
Programmable Switching Frequency
●●
Internal or Programmable Soft-Start
●●
PFM or Forced-PWM Mode of Operation
7) Connect the power-supply output to the VIN PCB
pad. Connect the supply ground to the GND PCB
pad.
●●
Open-Drain RESET Output
●●
Peak Current-Limit Protection
9) Enable the electronic load and verify that output voltage is 5V with respect to GND.
●●
Thermal Shutdown
10) Vary the input voltage from 6V to 60V.
●●
Proven PCB Layout
●●
Fully Assembled and Tested
11) Vary the load current from 1mA to 50mA and verify
that output voltage is 5V with respect to GND.
Ordering Information appears at end of data sheet.
19-7597; Rev 0; 4/15
8) Turn on the power supply.
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 shortcircuited load, and thereby cause the absolute maximum
rating of the VOUT 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 VOUT pin is not exceeded.
Evaluates: MAX17551 (TDFN) in
5V Output Voltage Applications
MAX17551 5V Output
Evaluation Kit (TDFN)
RESET Output
Detailed Description
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, 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 noload 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 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.
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 synchronize the EV kit switching frequency to an external clock
frequency.
The EV kit offers a fixed 5ms soft-start time. Connect
capacitor C4 to adjust the soft-start time (tSS). The
minimum soft-start time is related to the output
capacitance (COUT) and the output voltage (VOUT) by the
following equation.
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 undervoltage-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.
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
tSS > 0.05 x COUT x VOUT
where tSS is in milliseconds and COUT is in µF.
Use the following equation to determine the soft-start
capacitance value (CSS):
CSS = 6.25 x tSS
where tSS is in milliseconds and CSS is in nanofarads.
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
JU2
EN/UVLO PIN
VOUT OUTPUT
1-2
Open
Connected to VIN
Enabled
Open
1-2
Connected to GND
Disabled
1-2*
1-2
Connected to midpoint of R1, R2 resistor-divider
Enabled at VIN ≥ 6V
*Default position.
Table 2. MODE Control (JU3)
SHUNT POSITION
MODE PIN
MODE OF OPERATION
1-2
Connected to GND
Forced PWM
Open*
Unconnected
PFM
*Default position.
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Maxim Integrated │ 2
Evaluates: MAX17551 (TDFN) in
5V Output Voltage Applications
MAX17551 5V Output
Evaluation Kit (TDFN)
EV Kit Performance Report
toc1
100.0
90
90.0
80
80.0
70
EFFICIENCY (%)
EFFICIENCY (%)
100
VIN = 60V
VIN = 24V VIN = 36V
VIN = 48V
VIN = 12V
60
50
40
30
60.0
30.0
10.0
PFM MODE
0.0
10
VIN = 60V
PWM MODE
0
10
20
30
40
OUTPUT VOLTAGE
vs. LOAD CURRENT
VIN = 60V
VIN = 12V
4.99
0
10
20
30
40
50
LOAD CURRENT (mA)
LOAD TRANSIENT RESPONSE,
PFM MODE (LOAD CURRENT STEPPED
FROM 2mA to 27mA)
toc5
toc4
VIN = 24V
VIN = 48V
5.02
4.96
50
VIN = 36V
5.05
LOAD CURRENT (mA)
LOAD CURRENT (mA)
4.983
VIN = 48V
40.0
10
1
VIN = 36V
50.0
20.0
0
VIN = 12V
VIN = 24V
toc3
PFM MODE
5.08
70.0
20
OUTPUT VOLTAGE
vs. LOAD CURRENT
EFFICIENCY vs. LOAD CURRENT toc2
OUTPUT VOLTAGE (V)
EFFICIENCY vs. LOAD CURRENT
LOAD TRANSIENT RESPONSE
PFM OR PWM MODE (LOAD CURRENT
STEPPED FROM 25mA TO 50mA) toc6
PWM MODE
OUTPUT VOLTAGE (V)
4.981
VOUT
(AC)
4.979
VIN = 12V
4.977
VIN = 24V
VIN = 36V
VIN = 48V
FIGURE6
APPLICATION
CIRCUIT
VOUT=5V
100mV/div
4.973
IOUT
0
10
20
30
40
20mA/div
IOUT
VIN = 60V
4.975
50mV/div
VOUT
20mA/div
100µs/div
200µs/div
50
LOAD CURRENT (mA)
LOAD TRANSIENT RESPONSE
PWM MODE (LOAD CURRENT STEPPED
FROM NO LOAD TO 25mA) toc7
SOFT-START
toc8
BODE PLOT
5V/div
VEN/UVLO
PHASE
50mV/div
IOUT
20mA/div
100µs/div
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VOUT
20mA/div
IOUT
5V/div
VRESET
1ms/div
fCR = 16.3kHz,
PHASE MARGIN = 58°
GAIN
PHASE (º)
2V/div
GAIN (dB)
VOUT
(AC)
toc9
FREQUENCY(Hz)
Maxim Integrated │ 3
MAX17551 5V Output
Evaluation Kit (TDFN)
Evaluates: MAX17551 (TDFN) in
5V Output Voltage Applications
Component Suppliers
SUPPLIER
WEBSITE
Coilcraft, Inc.
www.coilcraft.com
Murata Americas
www.murata.com
Panasonic Corp.
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
www.maximintegrated.com
Maxim Integrated │ 4
MAX17551 5V Output
Evaluation Kit (TDFN)
Figure 1. MAX17551 5V EV Kit (TDFN) Component Placement
Guide—Component Side
Evaluates: MAX17551 (TDFN) in
5V Output Voltage Applications
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 │ 5
Evaluates: MAX17551 (TDFN) in
5V Output Voltage Applications
MAX17551 5V Output
Evaluation Kit (TDFN)
Ordering Information
PART
MAX17551ATBEVKIT#
TYPE
EV Kit
#Denotes RoHS compliant.
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Maxim Integrated │ 6
MAX17551 5V Output
Evaluation Kit (TDFN)
Evaluates: MAX17551 (TDFN) in
5V Output Voltage Applications
Revision History
REVISION
NUMBER
REVISION
DATE
0
4/15
DESCRIPTION
Initial release
PAGES
CHANGED
—
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
© 2015 Maxim Integrated Products, Inc. │ 7
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