MAXM17503EVKIT#

MAXM17503 5V Output Evaluation Kit General Description The MAXM17503 evaluation kit (EV kit) is a demonstration circuit of the MAXM17503 high-voltage, high-efficiency, current-mode scheme, synchronous step-down DC-DC switching power module. The EV kit is designed for a 5V output and delivers up to a 2.5A load current from a wide input voltage range of 11V to 60V. The EV kit switches at an optimal 500kHz switching frequency to allow the use of small component sizes, helping to minimize solution size while maintaining high performance. The EV kit provides a precision-enable input, an open-drain RESET output signal, and external frequency synchronization to provide a simple and reliable startup sequence and eliminate beat frequency between regulators. The EV kit also includes optional component footprints to program different output voltages, an adjustable input undervoltage lockout, and a soft-start time to control inrush current during startup. The MAXM17503 IC data sheet provides a complete description of the part that should be read in conjunction with this data sheet prior to modifying the demo circuit. Ordering Information appears at end of data sheet. Evaluates: MAXM17503 in 5V Output-Voltage Application Features ●● Highly Integrated Solution with Integrated Shield Inductor ●● Wide 11V to 60V Input Range ●● Preset 5V Output with a Fixed Resistor-Divider on the Feedback Pin (FB) ●● Programmable Output-Voltage Feature (0.9V to 12V) ●● Up to 2.5A Output Current ●● High 93% Efficiency (VIN = 12V, VOUT = 5V at 1.0A) ●● 500kHz Switching Frequency ●● Enable/UVLO Input, Resistor-Programmable UVLO Threshold ●● Adjustable Soft-Start Time ●● Selectable PWM, PFM, or DCM Mode ●● Open-Drain RESET Output ●● External Frequency Synchronization ●● Overcurrent and Overtemperature Protection ●● Low-Profile, Surface-Mount Components ●● Lead(Pb)-Free and RoHS Compliant ●● Fully Assembled and Tested ●● Proven PCB Layout 19-7624; Rev 0; 5/15 Evaluates: MAXM17503 in 5V Output-Voltage Application MAXM17503 5V Output Evaluation Kit Quick Start ●● 11V to 60V DC power supply (VIN) situated far from device circuit. When R4 is open, the device switches at a 500kHz switching frequency. On the bottom layer, additional footprints of optional components are included to ease board modification for different input/output configurations. ●● Dummy load capable of sinking 2.5A Soft-Start Input (SS) Recommended Equipment ●● MAXM17503 EV kit ●● Digital voltmeter (DVM) ●● 100MHz dual-trace oscilloscope 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) Set the power supply at a voltage between 11V and 60V. Disable the power supply. 2) Connect the positive and negative terminals of the power supply to IN and PGND PCB pads, respectively. 3) Connect the positive and negative terminals of the 2.5A load to OUT and PGND2 PCB pads, respectively, and set the load to 0A. 4) Connect the DVM across the OUT PCB pad and the PGND2 PCB pad. 5) Verify that no shunts are installed across pins 1-2 on jumper JU1 to enable UVLO (see Table 1 for details). 6) Verify that a shunt is installed across JU3 to disable external synchronization (see Table 3 for details). 7) Verify that a shunt is installed across JU2 to enable PWM mode (see Table 2 for details). 8) Enable the input power supply. 9) Verify the DVM displays 5V. 10) Increase the load up to 2.5A to verify the DVM continues displaying 5V. The device utilizes an adjustable soft-start function to limit inrush current during startup. The soft-start time is programmed by the value of the external capacitor from SS to GND (C1). The selected output capacitance (CSEL) and the output voltage (VOUT) determine the minimum value of C1, as shown by the following equation: C1 ≥ 28 × 10 −3 × C SEL × VOUT where C1 is in nF and CSEL is in µF The soft-start time (tSS) is calculated by the equation below: t SS = C1/ 5.55 where tSS is in ms and C1 is in nF. Programmable Undervoltage Lockout (UVLO) The EV kit offers an adjustable input undervoltagelockout level by resistor-dividers connecting between the IN, EN/UVLO, and GND pins. For normal operation, a shunt should not be installed across pins 1-2 on JU1 to enable the output through an internal pullup 3.3MΩ resistor from the EN/UVLO to IN pins. To disable the output, install the shunt across pins 1-2 on JU1 to pull the EN/UVLO pin to GND. See Table 1 for JU1 setting details. The EV kit also provides an optional R3 PCB footprint to program a UVLO threshold voltage at which an inputvoltage-level device turns on. The R3 resistor can be calculated by the following equation: Detailed Description of Hardware The MAXM17503 EV kit is a proven circuit to demonstrate the high-voltage, high-efficiency, and compact solution-size of the synchronous step-down DC-DC power module. The output voltage is preset for 5V to operate from 11V to 60V and provides up to 2.5A load current. The optimal frequency is set at 500kHz to maximize efficiency and minimize component size. The EV kit includes JU1 to enable/disable UVLO of the device, JU2 to configure in PWM, PFM, or DCM mode to improve lightload efficiency, and JU3 to enable/disable external clock synchronization (SYNC). The RESET PCB pad is also available for monitoring output-voltage regulation to enable/ disable the application circuit of the load. The electrolytic capacitor (C8) is required only when the VIN power supply is www.maximintegrated.com R3 = 4009.5 (VINU − 1.215) where VINU is the input voltage at which the device is required to turn on, and R3 unit is in kΩ. Table 1. UVLO Enable/Disable Configuration (JU1) SHUNT POSITION EN PIN MAXM17503_ OUTPUT Installed Connected to GND Disable Not installed* Connected to VIN Enable *Default position. Maxim Integrated │  2 Evaluates: MAXM17503 in 5V Output-Voltage Application MAXM17503 5V Output Evaluation Kit Mode Selection (MODE) The device’s MODE pin can be used to select among the PWM, PFM, or DCM modes of operation to improve constant frequency or high-efficiency at light load. The logic state of the MODE pin is latched when the VCC and EN/UVLO voltage exceeds the respective UVLO rising thresholds and all internal voltages are ready to allow LX switching. The changes on the MODE pin are ignored during normal operation. Refer to the MAXM17503 IC data sheet for more information on the PWM, PFM, and DCM modes of operation. Table 2 shows EV kit jumper settings that can be used to configure the desired mode of operation. amplitude should be greater than 50ns and 2.1V, respectively. The minimum external clock low-pulse width should be greater than 160ns, and the maximum external clock low-pulse amplitude should be less than 0.8V. Table 3 describes the connection of the SYNC pin. Setting VOUT with a Resistive Voltage-Divider at FB External Clock Synchronization (SYNC) The internal oscillator of the device can be synchronized to an external clock signal to eliminate beat frequency between regulators through the SYNC pin. The external synchronization clock frequency must be between 1.1fSW and 1.4fSW, where fSW is the frequency of operation set by R5. The minimum external clock high-pulse width and The EV kit is preset for 5V and offers an adjustable output voltage range as low as 0.9V up to 12V at 2.5A maximum load. The adjustable output voltage can be programmed by the set of resistor-dividers R1 and R2. Refer to Table 1 (Selection Component Values) of the MAXM17503 IC data sheet to select optimal component values for each specific input voltage range from 4.5V up to 60V and an output voltage from 0.9V up to 12V. To obtain an output voltage other than the default-setting outputs in Table 1, only seven component (R1, R2, C1–C4, and C8) values need to be modified by the equation described in the Setting the Output Voltage section of the MAXM17503 IC data sheet. Table 2. MODE Description (JU2) Table 3. SYNC Description (JU3) SHUNT POSITION MODE PIN MAXM17503_ MODE SHUNT POSITION SYNC PIN MAXM17503_ SYNC Not installed Unconnected PFM mode of operation 1-2 Connected to SGND SYNC feature unused 1-2 Connected to VCC DCM mode of operation Not installed* Connected to test loop on PCB Frequency can be synchronized with an external clock 2-3* Connected to GND *Default position. www.maximintegrated.com PWM mode of operation *Default position. Maxim Integrated │  3 MAXM17503 5V Output Evaluation Kit Evaluates: MAXM17503 in 5V Output-Voltage Application Typical Operating Characteristics VIN = 11V - 60V, VOUT = 5V, IOUT = 0 – 2.5A, TA = +25°C, unless otherwise noted. EFFICIENCY vs. OUTPUT CURRENT VOUT = 5V, PFM MODE toc01 100 90 80 70 VIN = 36V, fSW = 500kHz VIN = 12V, fSW = 500kHz 60 VIN = 48V, fSW = 500kHz VIN = 24V, fSW = 500kHz 50 EFFICIENCY (%) EFFICIENCY (%) 90 40 EFFICIENCY vs. OUTPUT CURRENT VOUT = 5V, PWM MODE toc02 100 500 1000 VIN = 24V, VIN = 12V, fSW = 500kHz fSW = 500kHz VIN = 36V, fSW = 500kHz VIN = 48V, 70 60 fSW = 500kHz 50 MODE = SGND MODE = OPEN 0 80 1500 2000 40 2500 0 500 OUTPUT CURRENT (mA) EFFICIENCY vs. OUTPUT CURRENT VOUT = 5V, DCM MODE toc03 100 5.4 70 VIN = 24V, fSW = 500kHz 60 VIN = 12V, fSW = 500kHz VIN = 48V, fSW = 500kHz 50 2500 VIN = 36V, fSW = 500kHz 0 500 1000 4.8 4.6 4.5 2500 LOAD AND REGULATION VOUT = 5V, PWM MODE 5.5 VIN = 48V, fSW = 500kHz VIN = 24V, fSW = 500kHz 4.7 MODE = VCC 2000 5 4.9 VIN = 36V, fSW = 500kHz 1500 5.1 MODE = OPEN 0 500 OUTPUT CURRENT (mA) 1000 1500 2000 2500 OUTPUT CURRENT (mA) toc05 LOAD AND LINE REGULATION VOUT = 5V, DCM MODE toc6 5.5 5.4 5.4 VIN = 12V, fSW = 500kHz 5.3 5.2 VIN = 36V, fSW = 500kHz 5.3 5.1 5 4.9 4.8 VIN = 24V, fSW = 500kHz 4.7 4.6 500 1000 1500 2000 OUTPUT CURRENT (mA) www.maximintegrated.com 5 4.9 VIN = 12V, fSW = 500kHz 4.7 4.6 MODE = SGND 0 5.1 4.8 VIN = 48V, fSW = 500kHz 2500 VIN = 48V, fSW = 500kHz VIN = 24V, fSW = 500kHz 5.2 VOUT (V) VOUT (V) 2000 5.2 VOUT (V) EFFICIENCY (%) VIN = 12V, fSW = 500kHz 5.3 80 4.5 1500 LOAD AND LINE REGULATION VOUT = 5V, PFM MODE toc04 5.5 90 40 1000 OUTPUT CURRENT (mA) 4.5 VIN = 36V, fSW = 500kHz MODE = VCC 0 500 1000 1500 2000 2500 OUTPUT CURRENT (mA) Maxim Integrated │  4 MAXM17503 5V Output Evaluation Kit Evaluates: MAXM17503 in 5V Output-Voltage Application Typical Operating Characteristics (continued) VIN = 11V - 60V, VOUT = 5V, IOUT = 0 – 2.5A, TA = +25°C, unless otherwise noted. LOAD CURRENT TRANSIENT RESPONSE VIN = 24V, VOUT = 5V, IOUT = 0.05A - 1.25A, toc07 MODE = OPEN LOAD CURRENT TRANSIENT RESPONSE VIN = 24V, VOUT = 5V, IOUT = 0.05A–1.25A, MODE = SGND toc08 1A/div IOUT 200mV/div (AC COUPLED) VOUT IOUT 1A/div VOUT 200mV/div (AC COUPLED) 100µs/div 200µs/div LOAD CURRENT TRANSIENT RESPONSE VIN = 24V, VOUT = 5V, IOUT = 1.25A-2.5A, MODE = SGND toc10 LOAD CURRENT TRANSIENT RESPONSE VIN = 24V, VOUT = 5V, IOUT = 0.05A–1.25A, MODE = VCC toc09 1A/div IOUT IOUT 1A/div 200mV/div (AC COUPLED) VOUT 200mV/div (AC COUPLED) VOUT 100µs/div 100µs/div 50 40 PHASE GAIN (dB) 30 toc11 150 120 90 20 60 10 30 0 0 GAIN -10 -20 -30 CROSSOVER FREQUENCY = 59.7kHz PHASE MARGIN = 64.1◦ -30 -40 -50 -60 PHASE MARGIN (°) CLOSED-LOOP BODE PLOT VIN = 24V, VOUT = 5V, IOUT = 2.5A, MODE = SGND -90 -120 1k 10k 100k -150 1Meg FREQUENCY (Hz) www.maximintegrated.com Maxim Integrated │  5 MAXM17503 5V Output Evaluation Kit Evaluates: MAXM17503 in 5V Output-Voltage Application Component Suppliers SUPPLIER WEBSITE Murata Americas www.murata.com NEC TOKIN America, Inc. www.nec-tokinamerica.com Panasonic Corp. www.panasonic.com SANYO Electric Co., Ltd. www.sanyodevice.com TDK Corp. www.component.tdk.com TOKO America, Inc. www.tokoam.com Note: Indicate that you are using the MAXM17503 when contacting these component suppliers. Component List and Schematic Refer to the following files attached to this data sheet for component information and schematic: ●● MAXM17503_EV_BOM.xls ●● MAXM17503EV_Schematic.pdf www.maximintegrated.com Maxim Integrated │  6 Evaluates: MAXM17503 in 5V Output-Voltage Application MAXM17503 5V Output Evaluation Kit Figure 1 MAXM17503 EV Kit Component Placement Guide— Component Side Figure 2 MAXM17503 EV Kit Component Placement Guide— Solder Side Figure 3. MAXM17503 EV Kit PCB Layout—Component Side www.maximintegrated.com Maxim Integrated │  7 Evaluates: MAXM17503 in 5V Output-Voltage Application MAXM17503 5V Output Evaluation Kit Figure 4. MAXM17503 EV Kit PCB Layout—PGND Layer 2 Figure 5. MAXM17503 EV Kit PCB Layout—PGND Layer 3 Figure 6. MAXM17503 EV Kit PCB Layout—Solder Side www.maximintegrated.com Maxim Integrated │  8 Evaluates: MAXM17503 in 5V Output-Voltage Application MAXM17503 5V Output Evaluation Kit Ordering Information PART TYPE MAXM17503EVKIT# EV Kit #Denotes RoHS compliant. www.maximintegrated.com Maxim Integrated │  9 Evaluates: MAXM17503 in 5V Output-Voltage Application MAXM17503 5V Output Evaluation Kit Revision History REVISION NUMBER REVISION DATE 0 5/15 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. │  10