MAXM17544 3.3V Output Evaluation Kit General Description Ordering Information appears at end of data sheet. 19-7625; Rev 0; 5/15 Features Highly Integrated Solution with Integrated Shield Inductor Wide 4.5V to 42V Input Range Preset 3.3V Output with a Fixed Resistor-Divider on FB (Feedback Pin) Programmable Output-Voltage Feature (0.9V to 12V) Up to 3.5A Output Current High 91.2% Efficiency (VIN = 12V, VOUT = 3.3V at 0.74A) 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 PRELIMINARY The MAXM17544 evaluation kit (EV kit) is a demonstration circuit of the MAXM17544 high-voltage, high-efficiency, current-mode scheme, synchronous step-down, DC-DC switching power module. The EV kit is designed for a 3.3V output and delivers up to 3.5A load current from a wide input-voltage range of 4.5V to 42V. 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 MAXM17544 IC data sheet provides a complete description of the part that should be read in conjunction with this evaluation kit data sheet prior to modifying the demo circuit. Evaluates: MAXM17544 in 3.3V Output-Voltage Application MAXM17544 3.3V Output Evaluation Kit Quick Start Recommended Equipment MAXM17544 EV kit 4.5V to 42V DC power supply (VIN) Dummy load capable of sinking 3.5A 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) Detailed Description of Hardware The EV kit is a proven circuit to demonstrate the highvoltage, high-efficiency, and compact solutionsize of the synchronous step-down, DC-DC power module. The output voltage is preset for 3.3V to operate from 4.5V to 42V and provides up to 3.5A load current. The optimal frequency is set at 500kHz to maximize efficiency and minimize component size. The EV kit includes jumpers JU1 to enable/disable UVLO of the device, JU2 to configure in PWM, PFM, or DCM mode in advantage of light-load efficiency, and JU3 to enable/disable external clock synchronize (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 situated far from device circuit. When R4 is open, the device switches at 500kHz switching frequency. www.maximintegrated.com On the bottom layer, additional footprints of optional components are included to ease board modification for different input/output configurations. Soft-Start Input (SS) 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 x 10 -3 x C SEL x VOUT where C1 is in nF and CSEL is in F 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 connected between 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 3.3M resistor from the EN/UVLO pin to IN pin. To disable the output, install the shunt across pins 1-2 on JU1 to pull EN/UVLO pin to GND. See Table 1 for JU1 jumper settings. The EV kit also provides an optional R3 PCB footprint to program a UVLO threshold voltage at which an input-voltage level device turns on. The R3 resistor can be calculated by the following equation: 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 k. Table 1. UVLO Enable/Disable Configuration (JU1) SHUNT POSITION EN PIN MAXM17544_OUTPUT Installed Connected to GND Disable Not installed* Connected to VIN Enable *Default position. Maxim Integrated 2 PRELIMINARY Set the power supply at a voltage between 4.5V and 42V. 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 3.5A 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 pin 1-2 on jumper JU1 to enable UVLO (see Table 1 for details). 6) Verify that a shunt is installed across JU3 to disable the 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 3.3V. 10) Increase the load up to 3.5A to verify the DVM continues displaying 3.3V. Evaluates: MAXM17544 in 3.3V Output-Voltage Application Evaluates: MAXM17544 in 3.3V Output-Voltage Application MAXM17544 3.3V Output Evaluation Kit Mode Selection (MODE) The device's MODE pin can be used to select among PWM, PFM, or DCM modes of operation in advance of constant frequency or high efficiency at light loads. The logic state of the MODE pin is latched when the VCC and EN/UVLO voltage exceed 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 MAXM17544 IC data sheet for more information on 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 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 to 1.4fSW, where fSW is the frequency of operation set by R5. The minimum external clock high pulse width and Table 2. MODE Description (JU2) Table 3. SYNC Description (JU3) SHUNT POSITION MODE PIN MAXM17544_MODE Not installed Unconnected PFM mode of operation 1-2 Connected to VCC DCM mode of operation 2-3* Connected to GND PWM mode of operation *Default position. www.maximintegrated.com SHUNT POSITION SYNC PIN MAXM17544_SYNC 1-2* Connected to SGND SYNC feature unused Not installed Connected to test loop on PCB Frequency can be synchronized with an external clock *Default position. Maxim Integrated 3 PRELIMINARY External Clock Synchronization (SYNC) The EV kit is preset for 3.3V and offers an adjustable output voltage range as low as 0.9V up to 12V at 3.5A maximum load. The adjustable output voltage can be programmed by the set of resistor dividers R1 and R2. Refer to the Table 1 (Selection Component Values) on the MAXM17544 IC data sheet to select optimal component values for each specific input voltage range from 4.5V up to 42V and an output voltage from 0.9V up to 12V. To obtain a different output voltage other than default setting outputs in Table 1, only six component (R1, R2, C1-C3, and C8) values need to be modified by the equation described in the Setting the Output Voltage section in the MAXM17544 IC data sheet. Evaluates: MAXM17544 in 3.3V Output-Voltage Application MAXM17544 3.3V Output Evaluation Kit Typical Operating Characteristics (VIN = 4.5V - 42V, VOUT = 3.3V, IOUT = 0 - 3.5A, TA = +25C, unless otherwise noted.) 100 90 90 80 80 70 VIN = 36V fSW = 500kHz VIN = 24V fSW = 500kHz 60 EFFICIENCY (%) EFFICIENCY (%) 100 90 VIN = 24V fSW = 500kHz 70 60 VIN = 12V fSW = 500kHz 50 VIN = 36V fSW = 500kHz 0 1000 2000 40 3000 OUTPUT CURRENT (mA) VIN = 5.0V fSW = 500kHz 3.4 2000 3000 3.2 VIN = 24V fSW = 500kHz 3.1 3.5 VIN = 12V fSW = 500kHz 1000 3.4 2000 VOUT (V) VIN = 5.0V fSW = 500kHz 3.4 VIN = 24V fSW = 500kHz 3.1 3 3000 LOAD REGULATION VOUT = 3.3V, DCM MODE 3.5 0 1000 2000 3000 toc05 VIN = 12V fSW = 500kHz 3.3 OUTPUT CURRENT (mA) 3.6 MODE = VCC VIN = 5.0V fSW = 500kHz 3.2 VIN = 36V fSW = 500kHz VIN = 36V fSW = 500kHz LOAD REGULATION VOUT = 3.3V, PWM MODE 3.6 MODE = OPEN 0 VIN = 12V fSW = 500kHz OUTPUT CURRENT (mA) toc04 3.3 3 1000 40 VOUT (V) VOUT (V) 3.5 60 MODE = SGND 0 VIN = 24V fSW = 500kHz 70 OUTPUT CURRENT (mA) LOAD REGULATION VOUT = 3.3V, PFM MODE 3.6 80 50 MODE = OPEN 40 EFFICIENCY vs. OUTPUT CURRENT VOUT = 3.3V, DCM MODE toc03 100 VIN = 36V fSW = 500kHz MODE = SGND 0 1000 2000 3000 OUTPUT CURRENT (mA) LOAD CURRENT TRANSIENT RESPONSE VIN = 24V, VOUT = 3.3V, IOUT = 0.05A TO 1.75A, toc07 MODE = OPEN toc06 VIN = 12V fSW = 500kHz 2A/div IOUT 3.3 3.2 VIN = 24V fSW = 500kHz 3.1 3 VIN = 36V fSW = 500kHz 200mV/div (AC COUPLED) VOUT MODE = VCC 0 1000 2000 3000 200s/div OUTPUT CURRENT (mA) www.maximintegrated.com Maxim Integrated 4 PRELIMINARY VIN = 12V fSW = 500kHz 50 EFFICIENCY vs. OUTPUT CURRENT VOUT = 3.3V, PWM MODE toc02 EFFICIENCY (%) EFFICIENCY vs. OUTPUT CURRENT VOUT = 3.3V, PFM MODE toc01 Evaluates: MAXM17544 in 3.3V Output-Voltage Application MAXM17544 3.3V Output Evaluation Kit Typical Operating Characteristics (continued) (VIN = 4.5V - 42V, VOUT = 3.3V, IOUT = 0 - 3.5A, TA = +25C, unless otherwise noted.) LOAD CURRENT TRANSIENT RESPONSE VIN = 24V, VOUT = 3.3V, IOUT = 0.05A TO 1.75A, MODE = VCC toc09 LOAD CURRENT TRANSIENT RESPONSE VIN = 24V, VOUT = 3.3V, IOUT = 0.05A TO 1.75A, MODE = SGND toc08 2A/div 200mV/div (AC COUPLED) VOUT 200s/div 200s/div CLOSED-LOOP BODE PLOT VIN = 24V, VOUT = 3.3V, IOUT = 3.5A, MODE = SGND 50 LOAD CURRENT TRANSIENT RESPONSE VIN = 24V, VOUT = 3.3V, IOUT = 1.75A TO 3.5A, MODE = SGND toc10 40 GAIN (dB) 2A/div IOUT PHASE VOUT 200s/div 150.00 120.00 30 90.00 20 60.00 10 30.00 0 0.00 GAIN -10 200mV/div (AC COUPLED) toc11 -30.00 -20 -60.00 -30 CROSSOVER FREQUENCY = 52.56kHz PHASE MARGIN = 66.7 -40 -50 1k 10k 100k -90.00 -120.00 -150.00 1Meg FREQUENCY (Hz) www.maximintegrated.com Maxim Integrated 5 PRELIMINARY 200mV/div (AC COUPLED) VOUT 2A/div IOUT PHASE MARGIN () IOUT MAXM17544 3.3V Output Evaluation Kit Evaluates: MAXM17544 in 3.3V 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 MAXM17544 when contacting these component suppliers. Component List and Schematic PRELIMINARY Refer to the following files attached to this data sheet for component information and schematic: MAXM17544_EV_BOM.xls MAXM17544_EV_Schematic.pdf www.maximintegrated.com Maxim Integrated 6 MAXM17544 3.3V Output Evaluation Kit Figure 2. MAXM17544 EV Kit Component Placement Guide-- Solder-Side Figure 3. MAXM17544 EV Kit PCB Layout--Component Side www.maximintegrated.com Maxim Integrated 7 PRELIMINARY Figure 1. MAXM17544 EV Kit Component Placement Guide-- Component-Side Evaluates: MAXM17544 in 3.3V Output-Voltage Application MAXM17544 3.3V Output Evaluation Kit Figure 5. MAXM17544 EV Kit PCB Layout--PGND Layer 3 Figure 6. MAXM17544 EV Kit PCB Layout--Solder-Side www.maximintegrated.com Maxim Integrated 8 PRELIMINARY Figure 4. MAXM17544 EV Kit PCB Layout--PGND Layer 2 Evaluates: MAXM17544 in 3.3V Output-Voltage Application MAXM17544 3.3V Output Evaluation Kit Evaluates: MAXM17544 in 3.3V Output-Voltage Application Ordering Information PART TYPE MAXM17544EVKIT# EV Kit #Denotes RoHS compliant. PRELIMINARY www.maximintegrated.com Maxim Integrated 9 Evaluates: MAXM17544 in 3.3V Output-Voltage Application MAXM17544 3.3V Output Evaluation Kit Revision History REVISION NUMBER REVISION DATE 0 5/15 DESCRIPTION Initial release PAGES CHANGED -- PRELIMINARY 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. (c) 2015 Maxim Integrated Products, Inc. 10 Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: Maxim Integrated: MAXM17544EVKIT#