MAX17521EVKIT#

MAX17521 Evaluation Kit Evaluates: MAX17521 in 3.3V and 5V Output-Voltage Application General Description Quick Start The MAX17521 evaluation kit (EV kit) provides a proven design to evaluate the MAX17521 dual high-efficiency, high-voltage, synchronous step-down DC-DC converter. The EV kit generates 3.3V and 5V output voltages at load currents up to 1A from a 7V to 60V input supply. The EV kit features a switching-frequency selector pin and individual mode-of-operation selector pins, enable/undervoltage-lockout (EN/UVLO) pins, programmable soft-start pins, and open-drain RESET_ signals for each output. Features ●● Operates from a 7V to 60V Input Supply ●● Dual-Output Voltage: 3.3V and 5V ●● Up to 1A Output Current ●● Pin-Selectable Switching Frequency ●● Enable/UVLO Input, Resistor-Programmable UVLO Threshold ●● Mode-Selection Pin for Each Output to Select Between PWM and PFM Modes ●● Adjustable Soft-Start Time for Each Output ●● Open-Drain RESET_ Signals for Each Output ●● External Frequency Synchronization ●● Overcurrent and Overtemperature Protection ●● Proven PCB Layout ●● Fully Assembled and Tested Ordering Information appears at end of data sheet. 19-7652; Rev 1; 7/17 Recommended Equipment ●● MAX17521 EV kit ●● 7V to 60V, 2A DC input power supply ●● Two loads capable of sinking 1A ●● Two digital voltmeters (DVM) Procedure The EV kit is fully assembled and tested. Follow the steps below to verify the board operation. Caution: Do not turn on the power supply until all connections are completed. 1) Set the power supply at a voltage between 7V and 60V. Disable the power supply. 2) Connect the positive terminal of the power supply to the VIN PCB pad and the negative terminal to the nearest PGND1 PCB pad. Connect the positive terminal of one of the 1A loads to the VOUT1 PCB pad and the negative terminal to the PGND1 PCB pad. Connect the positive terminal of the other 1A load to the VOUT2 PCB pad and the negative terminal to the PGND2 PCB pad. 3) Connect the DVMs across the VOUT1 PCB pad and the PGND1 PCB pad and across the VOUT2 PCB pad and the PGND2 PCB pad. 4) Verify that shunts are installed across pins 1-2 on jumpers J1, J2, and J3. 5) Select the shunt position on J5 and J6 depending on the intended mode of operation. 6) Turn on the DC power supply. 7) Enable the loads. 8) Verify that the DVMs display 3.3V and 5V. Evaluates: MAX17521 in 3.3V and 5V Output-Voltage Application MAX17521 Evaluation Kit Detailed Description The MAX17521 EV kit provides a proven design to evaluate the MAX17521 high-efficiency, high-voltage, dual synchronous step-down DC-DC converter. The EV kit generates 3.3V and 5V, at load currents up to 1A, from a 7V to 60V input supply. The EV kit features a switching-frequency selector pin and individual mode-of-operation selector pins, enable/ undervoltage-lockout (EN/UVLO) pins, programmable soft-start pins, and open-drain RESET signals for each output. Regulator Enable/Undervoltage-Lockout Level (EN/UVLO1, EN/UVLO2) The device offers an adjustable input undervoltagelockout level for each output. Set the voltage at which each converter turns on with a resistive voltage-divider connected from VIN to SGND (viewable here). Connect the center node of the divider to EN/UVLO pin. Choose RTOP to be 3.3MΩ, and then calculate RBOTTOM as: R BOTTOM = Soft-Start Input (SS) The device implements adjustable soft-start operation to reduce inrush current. Capacitors connected from the SS pins to SGND programs the soft-start time for the corresponding output voltage. The selected output capacitance (CSEL) and the output voltage (VOUT) determine the minimum required soft-start capacitor as follows: R TOP × 1.218 VINU − 1.218 Where VINU is the input voltage at which a particular converter is required to turn on. Install a shunt across pins 1-2 on J1 and J2 to enable the EV kit’s outputs. See Table 1 and Table 2 for proper jumper settings. CSS ≥ 56 x 10-6 x CSEL x VOUT The soft-start time (tSS) is related to the capacitor connected at SS (CSS) by the following equation: tSS = CSS/(5.55 x 10-6) For example, to program a 1ms soft-start time, a 5.6nF capacitor should be connected from the SS pin to SGND. Table 1. Regulator Enable (EN/UVLO1) Description (J1) Table 2. Regulator Enable (EN/UVLO2) Description (J2) SHUNT POSITION EN/UVLO1 PIN MAX17521_ OUTPUT1 SHUNT POSITION EN/UVLO2 PIN MAX17521_ OUTPUT2 1-2* Connected to VIN1 Enabled 1-2* Connected to VIN2 Enabled Not installed 2-3 Connected to the center Enabled, UVLO level set node of resistor-divider through the R3 and R4 R3 and R4 resistors Connected to SGND *Default position. www.maximintegrated.com Disabled Not installed 2-3 Connected to the center Enabled, UVLO level set node of resistor-divider through the R11 and R12 R11 and R12 resistors Connected to SGND Disabled *Default position. Maxim Integrated │  2 Evaluates: MAX17521 in 3.3V and 5V Output-Voltage Application MAX17521 Evaluation Kit Mode Selection (MODE1, MODE2) The device’s MODE_ pins can be used to select between the PWM and PFM modes of operation. Refer to the MAX17521 IC data sheet for more information on the PWM and PFM modes of operation. Table 3 and Table 4 show EV kit jumper settings that can be used to configure the desired mode of operation. Switching-Frequency Selection (FSEL) The device’s FSEL pin can be used to select between 560kHz and 300kHz switching frequency. The EV kit is designed to operate at 560kHz switching frequency. If intended to operate at 300kHz, the values of the inductors, input and output capacitors, and the compensation components should be modified according to formulae provided in the MAX17521 IC data sheet. Table 5 shows EV kit jumper settings that can be used to configure the switching frequency. Table 3. MODE1 Description (J6) SHUNT POSITION MODE1 PIN MAX17521_ MODE1 Not installed* Unconnected PFM mode of operation 1-2 Connected to SGND PWM mode of operation External Clock Synchronization (SYNC) The internal oscillator of the device can be synchronized to an external clock signal on 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 the FSEL pin. See Table 6 for jumper settings. Table 5. FSEL Description (J4) SHUNT POSITION FSEL PIN Switching Frequency Not installed* Unconnected 560kHz 1-2 Connected to SGND 300kHz *Default position. Table 6. SYNC Description (J7) SHUNT POSITION FSEL PIN SYNC 1-2 Connected to test loop on PCB Frequency can be synchronized with an external clock 2-3* Connected to SGND SYNC feature unused *Default position. *Default position. Table 4. MODE2 Description (J5) SHUNT POSITION MODE2 PIN MAX17521_ MODE2 Not installed* Unconnected PFM mode of operation 1-2 Connected to SGND PWM mode of operation *Default position. www.maximintegrated.com Maxim Integrated │  3 Evaluates: MAX17521 in 3.3V and 5V Output-Voltage Application MAX17521 Evaluation Kit EV Kit Performance Report (24V input voltage, unless otherwise noted.) 80 70 70 60 50 40 PWM MODE 30 60 50 40 PWM MODE 30 20 20 10 0 PFM MODE 90 80 EFFICIENCY (%) EFFICIENCY (%) TOC01 PFM MODE 90 3.3V OUTPUT, EFFICIENCY vs. LOAD CURRENT 100 10 VIN = 24V, FSEL = OPEN 1 10 100 0 1000 VIN = 24V, FSEL = OPEN 1 10 LOAD CURRENT (mA) OUTPUT VOLTAGE (V) OUTPUT VOLTAGE (V) 5.00 4.95 PFM MODE 3.39 3.37 3.35 3.33 3.31 3.29 3.27 PWM MODE 400 600 800 1000 3.25 PWM MODE 0 200 400 600 800 LOAD CURRENT (mA) LOAD CURRENT (mA) 5V OUTPUT, PWM MODE, (LOAD CURRENT STEPPED FROM 0.5A TO 1A) 5V OUTPUT, PWM MODE, (LOAD CURRENT STEPPED FROM 0 TO 0.5A) TOC05 VOUT1 (AC) 100mV/div I OUT1 500mA/div 100μs/div www.maximintegrated.com TOC04 3.41 5.05 200 VIN = 24V, FSEL = OPEN 3.43 PFM MODE 0 1000 3.3V OUTPUT, LOAD REGULATION 3.45 TOC03 VIN = 24V, FSEL = OPEN 5.10 100 LOAD CURRENT (mA) 5V OUTPUT, LOAD REGULATION 5.15 4.90 TOC02 5V OUTPUT, EFFICIENCY vs. LOAD CURRENT 100 1000 TOC06 VOUT1 (AC) 100mV/div I OUT1 200mA/div 100μs/div Maxim Integrated │  4 Evaluates: MAX17521 in 3.3V and 5V Output-Voltage Application MAX17521 Evaluation Kit EV Kit Performance Report (continued) (24V input voltage, unless otherwise noted.) 5V OUTPUT, PFM MODE, (LOAD CURRENT STEPPED FROM 5mA TO 500mA) 3.3V OUTPUT, PWM MODE, (LOAD CURRENT STEPPED FROM 0.5A TO 1A) TOC07 VOUT1 (AC) TOC08 VOUT2 (AC) 200mV/div 100mV/div I OUT2 I OUT1 500mA/div 200mA/div 10ms/div 100μs/div 3.3V OUTPUT, PWM MODE, (LOAD CURRENT STEPPED FROM 0 TO 0.5A) 3.3V OUTPUT, PFM MODE, (LOAD CURRENT STEPPED FROM 5mA TO 0.5A) VOUT2 (AC) TOC09 50mV/div I OUT2 200mA/div VOUT2 (AC) 100mV/div I OUT2 200mA/div 100μs/div 1ms/div BODE PLOT (5V OUTPUT, 1A LOAD) 30 BODE PLOT (3.3V OUTPUT, 1A LOAD) toc11 30 100 PHASE 20 20 100 50 0 0 GAIN (dB) GAIN GAIN 0 0 PHASE (º) 10 PHASE (°) GAIN (dB) toc12 PHASE 50 10 TOC10 -10 -10 -50 -50 -20 -20 VOUT = 5V fCR = 51kHz, -30 PHASE MARGIN = 62.3° 104 www.maximintegrated.com FREQUENCY(Hz) -100 105 -30 VOUT = 3.3V fCR = 51KHz, PHASE MARGIN = 62.3° -100 105 104 FREQUENCY(Hz) Maxim Integrated │  5 Evaluates: MAX17521 in 3.3V and 5V Output-Voltage Application MAX17521 Evaluation Kit MAX17521 EV Kit Bill of Materials Designator Value Description Part Number C1, C2 2.2μF/X7R/100V/1210 Input Capacitor GRM32ER72A225KA35L Murata 2 GRM188R70J105KA01 Murata 2 Murata 2 C3 C4 C5, C6 10μF/X7R/10V/1210 22μF/X7R/10V/1210 Output Capacitor Output Capacitor GRM32DR71A106KA01 GRM32ER71A226ME20 1μF/X7R/6.3V/0603 VCC Bypass Capacitor 2700pF/X7R/50V/0402 Compensation Capacitor GRM155R71H272KA01J Compensation Capacitor GRM1555C1H220JA01D Murata 1 C10 33pF Compensation Capacitor L1 22μH Inductor R1 82.5kΩ±1%, 0402 FB divider Resistor R3, R11 3.3MΩ±1%, 0603 EN divider Resistor R5 15.8kΩ±1%, 0402 Compensation Resistor Vishay Dale 1 R8 22.1kΩ±1%, 0402 Compensation Resistor Vishay Dale 1 R10 20.5kΩ±1%, 0402 FB divider Resistor Vishay Dale 1 L2 R2 R4 R6, R7 R9 R12 U1 22pF 15μH 18.2kΩ±1%, 0402 750kΩ±1%, 0603 XAL4040-153 FB divider Resistor Murata Murata Coilcraft Coilcraft EN divider Resistor 54.9kΩ±1%, 0402 FB divider Resistor 1 1 2 Vishay Dale MAX17521ATG+ 1 Vishay Dale Vishay Dale DC-DC Converter 1 1 Vishay Dale EN divider Resistor 2 Vishay Dale Vishay Dale RESET\ pull-up Resistor MAX17521 XAL5050-223 Inductor 10kΩ±1%, 0402 1MΩ±1%, 0603 GRM1555C1H330JA01D Murata 1 3300pF/X7R/50V/0402 C12 GRM155R71H332KA01 Murata C7, C8 C9, C11 Soft-start Capacitor Manufacturer Quantity Vishay Dale Maxim 1 1 2 1 1 1 Component Suppliers SUPPLIER WEBSITE Coilcraft, Inc. www.coilcraft.com Murata Americas www.murata.com Vishay www.vishay.com Note: Indicate that you are using the MAX17521 when contacting these component suppliers. Ordering Information PART MAX17521EVKITA# #Denotes RoHS-compliant. www.maximintegrated.com TYPE EV kit Maxim Integrated │  6 SGND1 RESETN1 EN/UVLO1 PGND1 VIN1 PGND2 SGND RESETN1 EN/UVLO1 PGND1 SGND R1 VOUT1 J1 SGND R2 18.2K 82.5K C1 2.2UF 1.0UF C5 VCC1 EN/UVLO1 VIN1 22UH SGND R4 750K R3 3.3M FB1 SGND 2 PGND1 C3 10UF 2 2 1 SGND FB1 C7 3300PF PGND1 J6 1 2 3 4 5 6 1 J7 2 C10 33PF SS1 FB1 VCC1 J5 SGND SGND EN/UVLO1 VIN1 PGND1 U1 3 SGND VIN2 RESETN1 2700PF C9 15.8K R5 LX1 SGND1 L1 MODE1 COMP1 1 SYNC RESET1 VOUT1 2 MODE2 FREQ VOUT1 1 J3 1 SGND 10K R6 1 RESETN2 J4 10K R7 SGND 18 17 16 15 14 13 15UH L2 MAX17521 SGND2 SS2 FB2 VCC2 EN/UVLO2 VIN2 PGND2 LX2 RESET2 SYNC 1 3 2 1 PGND2 COMP2 24 23 22 21 20 19 EP 25 7 8 9 10 11 12 www.maximintegrated.com C4 22UF 2 SGND VCC2 SGND 3300PF C8 SGND C11 2700PF 22.1K R8 2 SGND 1M R12 3.3M R11 VIN2 SGND C6 1.0UF FB2 VCC2 EN/UVLO2 PGND2 VCC1 2 VOUT2 1 C12 22PF SGND 3 VIN1 J2 FB2 EN/UVLO2 RESETN2 PGND2 C2 2.2UF SGND SGND R10 20.5K R9 54.9K VOUT2 SGND2 EN/UVLO2 RESETN2 PGND4 VIN2 PGND3 VOUT2 MAX17521 Evaluation Kit Evaluates: MAX17521 in 3.3V and 5V Output-Voltage Application MAX17521 EV Kit Schematic Maxim Integrated │  7 MAX17521 Evaluation Kit Evaluates: MAX17521 in 3.3V and 5V Output-Voltage Application MAX17521 EV Kit PCB Layout PCB Component Placement Guide: Component Side PCB Layout: Component Side PCB Layout: Inner Layer 1 PCB Layout: Inner Layer 2 www.maximintegrated.com Maxim Integrated │  8 MAX17521 Evaluation Kit Evaluates: MAX17521 in 3.3V and 5V Output-Voltage Application MAX17521 EV Kit PCB Layout (continued) PCB Layout: Solder Side PCB Layout: Solder Mask PCB Layout: Component Placement Guide: Bottom Solder Mask www.maximintegrated.com Maxim Integrated │  9 MAX17521 Evaluation Kit Evaluates: MAX17521 in 3.3V and 5V Output-Voltage Application Revision History REVISION NUMBER REVISION DATE PAGES CHANGED 0 6/15 Initial release 1 7/17 Corrected symbols in equations in the Soft-Start Input (SS) and Regulator Enable/Undervoltage-Lockout Level (EN/UVLO1, EN/UVLO2) sections. Updated part number in Ordering Information table to MAX17521EVKITA#. DESCRIPTION — 2, 6 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. ©  2017 Maxim Integrated Products, Inc. │  10