Evaluates: MAX17531 (TDFN) in 5V Output Voltage Applications

Evaluates: MAX17531 (TDFN) in 5V Output Voltage Applications
Evaluates: MAX17531 (TDFN) in
5V Output Voltage Applications
MAX17531 5V Output
Evaluation Kit (TDFN)
General Description
The MAX17531 5V evaluation kit (EV kit) (TDFN) is a fully
assembled and tested circuit board that demonstrates the
performance of the MAX17531 42V, 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 42V 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 comes installed with the MAX17531ATB+ in
a 10-pin (3mm x 2mm) lead(Pb)-free/RoHS-compliant
TDFN package.
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).
2) Verify that jumper JU3 (MODE-PFM operation) is open.
3) Set the electronic load to constant-current mode,
50mA, and disable the electronic load.
4) Connect the electronic load’s positive terminal to the
VOUT PCB pad. Connect the negative terminal to
the GND PCB pad.
5) Connect the voltmeter across the VOUT and GND
PCB pads.
6) Set the power-supply output to 24V. Disable the
power supply.
Features
●●
6V to 42V Input Voltage Range
7) Connect the power-supply output to the VIN PCB
pad. Connect the supply ground to the GND PCB
pad.
●●
5V Output, 50mA Continuous Current
8) Turn on the power supply.
●●
26µA No-Load Supply Current
9)
●●
EN/UVLO for On/Off Control and Programmable
Input Undervoltage Lockout
10) Vary the input voltage from 6V to 42V.
●●
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
Quick Start
Recommended Equipment
●●
MAX17531 5V EV kit (TDFN)
●●
42V adjustable, 0.5A DC power supply
●●
Electronic load up to 50mA
●●
Voltmeter
19-7709; Rev 0; 7/15
Enable the electronic load and verify that output voltage
is 5V with respect to GND.
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 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.
Ordering Information appears at end of data sheet.
Evaluates: MAX17531 (TDFN) in
5V Output Voltage Applications
MAX17531 5V Output
Evaluation Kit (TDFN)
RESET Output
Detailed Description
The MAX17531 5V EV kit (TDFN) is a fully assembled and
tested circuit board that demonstrates the performance
of the MAX17531 42V, 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 42V 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 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
MAX17531 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. Refer
to the External Synchronization section in the MAX17531
IC data sheet for additional information on configuring the
external clock.
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: MAX17531 (TDFN) in
5V Output Voltage Applications
MAX17531 5V Output
Evaluation Kit (TDFN)
EV Kit Performance Report
90
80
80
70
70
VIN = 12V
50
EFFICIENCY (%)
EFFICIENCY (%)
90
60
VIN = 36V
VIN = 24V
40
20
20
10
10
1
0
10
VIN = 36V
PWM MODE
0
10
20
30
40
VIN = 36V
5.05
OUTPUT VOLTAGE
vs. LOAD CURRENT
0
10
20
30
40
50
LOAD CURRENT (mA)
LOAD TRANSIENT RESPONSE
PFM OR PWM MODE (LOAD CURRENT
STEPPED FROM 25mA TO 50mA) toc6
LOAD TRANSIENT RESPONSE,
PFM MODE (LOAD CURRENT STEPPED
FROM 2mA to 27mA)
toc5
toc4
VIN = 12V
4.99
4.96
50
VIN = 24V
5.02
LOAD CURRENT (mA)
LOAD CURRENT (mA)
4.983
VIN = 24V
40
toc3
PFM MODE
5.08
VIN = 12V
50
30
PFM MODE
OUTPUT VOLTAGE
vs. LOAD CURRENT
toc2
5.11
60
30
0
EFFICIENCY vs. LOAD CURRENT
100
OUTPUT VOLTAGE (V)
EFFICIENCY vs. LOAD CURRENT toc1
100
VOUT
(AC)
4.979
VIN = 12V VIN = 24V
4.977
VIN =
36V
IOUT
PWM MODE
0
10
20
20mA/div
IOUT
4.975
4.973
FIGURE6
APPLICATION
CIRCUIT
VOUT=5V
50mV/div
VOUT
100mV/div
30
40
50
20mA/div
200µs/div
100µs/div
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
VOUT
(AC)
PHASE
50mV/div
IOUT
20mA/div
100µs/div
www.maximintegrated.com
toc9
GAIN (dB)
2V/div
VOUT
20mA/div
IOUT
5V/div
VRESET
1ms/div
fCR = 16.3kHz,
PHASE MARGIN = 58°
GAIN
PHASE (º)
OUTPUT VOLTAGE (V)
4.981
FREQUENCY(Hz)
Maxim Integrated │ 3
MAX17531 5V Output
Evaluation Kit (TDFN)
Evaluates: MAX17531 (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 MAX17531ATB when contacting these component suppliers.
Component List and Schematic
See the following links for component information and
schematics:
●● MAX17531EV TDFN BOM
●● MAX17531EV TDFN Schematic
www.maximintegrated.com
Maxim Integrated │ 4
MAX17531 5V Output
Evaluation Kit (TDFN)
Figure 1. MAX17531 5V EV Kit (TDFN) Component Placement
Guide—Component Side
Evaluates: MAX17531 (TDFN) in
5V Output Voltage Applications
Figure 2. MAX17531 5V EV Kit (TDFN) PCB Layout—
Component Side
Figure 3. MAX17531 5V EV Kit (TDFN) PCB Layout—
Solder Side
www.maximintegrated.com
Maxim Integrated │ 5
Evaluates: MAX17531 (TDFN) in
5V Output Voltage Applications
MAX17531 5V Output
Evaluation Kit (TDFN)
Ordering Information
PART
MAX17531ATBEVKIT#
TYPE
EV Kit
#Denotes RoHS compliant.
www.maximintegrated.com
Maxim Integrated │ 6
MAX17531 5V Output
Evaluation Kit (TDFN)
Evaluates: MAX17531 (TDFN) in
5V Output Voltage Applications
Revision History
REVISION
NUMBER
REVISION
DATE
0
7/15
DESCRIPTION
Initial release
PAGES
CHANGED
—
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.
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
+
1
C1
22UF
GND 50V
2
RT/SYNC
JU1
JU2
LX
10
GND
9
EN/UVLO VOUT
6
C4
OPEN
3
4
RT/SYNC
SS
FB
1
2
2
MODE
EP
RESET
7
GND
R4
261K
R5
R6 VOUT
100K
8
JU3
22.1
5
MODE
R2
787K
C3
10UF
6.3V
R7
C5
0.22UF
R3
140K
VOUT
5V,50MA
L1
330UH
C6
47PF
1
1
EN/UVLO
VIN
C2
1UF
50V
R1
3.01M
2
GND
VOUT
U1
MAX17531ATB+
VIN
6V TO 42V
49.9K
RESET
Serial No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Description
22μF, 50V electrolytic capacitor (6.3mm x 6.3mm)
1μF ±10%, 50V X7R ceramic capacitor (0805)
10μF ±10%, 6.3V X7R ceramic capacitor (0805)
Not installed, OPEN (0402)
0.22µF ±10%, 16V X7R ceramic capacitor (0402)
47pF ±5% 50V COG ceramic capacitor (0402)
2-pin headers
330µH, 150mA inductor
3.01M ohm ±1%, resistor (0402)
787k ohm ±1%, resistor (0402)
140k ohm ±1%, resistor (0402)
261k ohm ±1%, resistor (0402)
49.9k ohm ±1%, resistor (0402)
100k ohm ±1%, resistor (0402)
22.1 ohm ±1%, resistor (0402)
42V, 50mA, ultra-small, highefficiency, synchronous step-down DC-DC
converter with 22μA noload supply current (10 TDFN-EP*) Maxim
MAX17531ATB+
Shunt
Quantity Designator
1
C1
1
C2
1
C3
0
C4
1
C5
1
C6
3
JU1-JU3
1
L1
1
R1
1
R2
1
R3
1
R4
1
R5
1
R6
1
R7
Part Number
PANASONIC EEEFK1H220P
MURATA GRM21BR71H105K
Murata GRM21BR70J106K
Murata GRM155R71C224K
MURATA GRM1555C1E470J
Sullins: PTC36SAAN
Coilcraft LPS5030-334M
1
U1
MAX17531ATB+
3
See Jumper
Table
SULLINS STC02SYAN
JUMPER
JU1
JU2
JU3
Jumper Table
SHUNT POSITION
1-2
1-2
OPEN
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