Evaluates: MAX17557 5V Output-Voltage Application MAX17557 5V Output Evaluation Kit General Description The MAX17557 5V-output evaluation kit (EV kit) provides a proven design to evaluate the MAX17557 high-voltage, high-efficiency, synchronous step-down DC-DC controller. The EV kit provides 5V/10A at the output from a 6.5V to 60V input supply. The switching frequency of the EV kit is preset to 350kHz for optimum efficiency and component size. The EV kit features Enable/UVLO Input, resistorprogrammable UVLO threshold, adjustable soft-start time, open-drain PGOOD output, and overcurrent and overtemperature protection. Features ●● Operates from a 6.5V to 60V Input Supply ●● 5V Output Voltage Quick Start Recommended Equipment ●● MAX17557 5V-output EV kit ●● 6.5V to 60V, 10A DC-input power supply ●● Load capable of sinking 10A ●● Digital voltmeter (DVM) Procedure The EV kit is fully assembled and tested. Follow the steps below to verify the board operation. Caution: Do not turn on power supply until all connections are completed. 1) 2) ●● Up to 10A Output Current ●● 350kHz Switching Frequency ●● Enable/UVLO Input, Resistor-Programmable UVLO Threshold ●● Adjustable Soft-Start Time ●● Open-Drain PGOOD Output ●● Overcurrent (OCP) and Overtemperature (OTP) Protection ●● Proven PCB Layout ●● Fully Assembled and Tested Ordering Information appears at end of data sheet. 319-100068; Rev 0; 8/17 3) 4) 5) 6) 7) Set the power supply at a voltage between 6.5V and 60V. Disable the power supply. Connect the positive terminal of the power supply to the VIN PCB pad and the negative terminal to the nearest PGND PCB pad. Connect the positive terminal of the 10A load to the VOUT PCB pad and the negative terminal to the nearest PGND PCB pad. Connect the DVM across the VOUT PCB pad and the nearest PGND PCB pad. Place the shunt on the jumpers JU1, JU3, and JU4 according to the intended operation (see Tables 1, 2, and 3 for details). Turn on the DC power supply. Enable the load. Verify that the DVM displays 5V. Evaluates: MAX17557 5V Output-Voltage Application MAX17557 5V Output Evaluation Kit Detailed Description of Hardware The MAX17557 5V-output evaluation kit (EV kit) is a proven design to evaluate the MAX17557 high-voltage, high-efficiency, synchronous step-down DC-DC controller. The EV kit provides 5V/10A at the output from a 6.5V to 60V input supply. The switching frequency of the EV kit is preset to 350kHz for optimum efficiency and component size. The EV kit features current sensing using either an external current-sense resistor for accuracy or an inductor DCR for improved system efficiency. Current foldback limits MOSFET power dissipation under short-circuit conditions. The EV kit includes an EN/UVLO PCB pad and jumperJU4 to enable the output at a desired input voltage. A PGOOD PCB pad is available for monitoring when the converter output is in regulation. Setting the Input Undervoltage Lockout Level The EN pin can be open or pulled up to a voltage between 1.25V and 5.5V to turn on the controller. Figure 1 shows the possible configurations. The EN pin can be used as input undervoltage lockout detector with a typical hysteresis of 100mV. As shown in Figure 1, the input voltage at which the controller of the IC turns on, can be set with a resistordivider connected to EN from IN to GND. Select R2 = 10kΩ and calculate R1 based on the following equation: R1 = R2 × 1.25 where VINUVLO is the input voltage at which the controller should be enabled. VIN_MIN TO VIN_MAX 4.5V TO 60V (VIN_UVLO − 1.25) IN IN R1 MAX17557 MAX17557 EN R2 EN ENABLE AS INPUT UVLO ALWAYS-ON CONFIGURATION VIN_MAX / VIN_MIN ≤ 4.4 4.5V TO 60V VIN_MIN TO VIN_MAX IN IN R1 MAX17557 MAX17557 EN >1.25V D1 4.7V EN TURN ON/OFF BY LOGIC SIGNAL R2 ENABLE AS INPUT UVLO VIN_MAX / VIN_MIN ≥ 4.4 Figure 1. Setting the Input Under Voltage Lockout www.maximintegrated.com Maxim Integrated │ 2 Evaluates: MAX17557 5V Output-Voltage Application MAX17557 5V Output Evaluation Kit Adjusting Output Voltage The output voltage of the converter is set by connecting a resistor-divider to FB from the output to GND (Figure 2). Select R3 using the following equation, based on the offset introduced on the output voltage by the FB leakage. Let α be the offset introduced on the output voltage: R3 ≤ VOUT R3 MAX17557 FB α IFB_ R4 where: α = offset introduced on the output voltage IFB = FB leakage current (±100nA max) Figure 2: Adjusting Output Voltage For example, for VOUT = 5V, α = 0.1% of VOUT (= 5mV). Frequency Selection (RT) R3 ≤ 50kΩ Calculate R4 with the following equation: R4 = R1 V OUT 0.8 − 1 Soft-Start Capacitor Selection Soft-start time is programmed by connecting a capacitor from the SS pin to GND. An internal 5µA current source charges the capacitor at the SS pin providing a linear ramping voltage for output-voltage reference. The softstart time is calculated based on the following equation: t= SS C SS × 0.8V 5µA The selection of switching frequency is a tradeoff between efficiency and component size. Low-frequency operation increases efficiency by reducing MOSFET switching losses and gate-drive losses, but requires a larger inductor and/or capacitor to maintain low output-ripple voltage. The switching frequency of the device can be programmed between 100kHz and 2.2MHz using the RT pin. Connect a resistor from RT to GND to set the regulator’s switching frequency. Leave RT open for the default 350kHz frequency. The following formula can be used to find the required resistor for a given switching frequency. = R RT 19 × 10 3 − 1.7 f SW where RRT is in kΩ and fSW is in kHz. Leaving the RT pin open causes the device to operate at the default switching frequency of 350kHz. Table 1. JU1: Switching Frequency Selection Jumper JUMPER SHUNT POSITION Not Installed JU1 1-2 2-3 www.maximintegrated.com R3 RT MAX17557 SWITCHING FREQUENCY Not installed Unconnected Default 350kHz R3 is used Connected to GND through R3 fSW = (19000) / (RRT + 1.7) X Connected to VCCINT Default 350kHz Controller does not start Maxim Integrated │ 3 Evaluates: MAX17557 5V Output-Voltage Application MAX17557 5V Output Evaluation Kit Table 2. JU3: Overcurrent Protection Mode Select JUMPER SHUNT POSITION ILIMSEL 1-2 Connected to VCCINT Latch-off Mode 2-3 Connected to GND Foldback Mode JU3 MODE Table 3. JU4: Controller Enable (EN/UVLO) Description JUMPER SHUNT POSITION EN MAX17557 OUTPUT Not installed Unconnected Enabled 1-2 Connected to the input UVLO divider midpoint. Enabled, UVLO level is set by the resistor divider from VIN to GND. 2-3 Connected to GND Disabled JU4 MAX17557 EV Kit Performance Report VIN = 24V, unless otherwise noted, 100 LOAD AND LINE REGULATION 5V OUTPUT EFFICIENCY vs. LOAD CURRENT 5V OUTPUT toc01 90 5.11 VIN = 12V 5.10 OUTPUT VOLTAGE(V) EFFICIENCY(%) 80 VIN = 60V 70 VIN = 48V 60 VIN = 36V 50 VIN = 24V 40 30 0.01 toc02 5.12 VIN = 6.5V 0.1 1 5.08 VIN = 24V 5.07 5.06 VIN = 12V 5.05 5.04 10 VIN = 48V VIN = 6.5V 5.09 LOAD CURRENT(A) VIN = 60V VIN = 36V 0 5 10 LOAD CURRENT (A) SOFT-START WITH 2.5V PREBIAS, 5V OUTPUT SOFT-START/SHUTDOWN FROM EN/UVLO 5V OUTPUT toc03 toc04 5V/div VEN/UVLO 5V/div VOUT 2V/div IOUT 10A/div 5V/div VPGOOD VEN/UVLO 1V/div VOUT 5V/div VPGOOD 2ms/div 1ms/div CONDITIONS: 10A LOAD CURRENT www.maximintegrated.com Maxim Integrated │ 4 Evaluates: MAX17557 5V Output-Voltage Application MAX17557 5V Output Evaluation Kit MAX17557 EV Kit Performance Report (continued) VIN = 24V, unless otherwise noted, LOAD TRANSIENT RESPONSE 5V OUTPUT toc05 VOUT (AC) 100mV/div IOUT 5A/div 200µs/div CONDITIONS: LOAD CURRENT STEPPED FROM 5A TO 10A 5V OUTPUT BODE PLOT CONDITIONS:10A LOAD CURRENT LOAD TRANSIENT RESPONSE 5V OUTPUT toc07 toc06 IOUT 5A/div 400µs/div CONDITIONS: LOAD CURRENT STEPPED FROM 0.1A TO 5A PHASE PHASE(°) 200mV/div GAIN (dB) VOUT (AC) GAIN CROSSOVER FREQUENCY = 24.5kHz, PHASE MARGIN = 64.6° 103 104 105 FREQUENCY (Hz) Component List SUPPLIER WEBSITE Coilcraft, Inc. www.coilcraft.com Murata Americas www.murataamericas.com Panasonic Corp. www.panasonic.com Renesas Electronics www.renesas.com Diode Inc. www.diodes.com Note: Indicate that you are using the MAX17557 when contacting these component suppliers. www.maximintegrated.com Maxim Integrated │ 5 Evaluates: MAX17557 5V Output-Voltage Application MAX17557 5V Output Evaluation Kit Ordering Information PART TYPE MAX17557EVKIT# EVKIT MAX17557 EV System Bill of Materials No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Description 0.1µF 10%, 100V ,X7R,Ceramic capacitor (0603) 4.7µF 20%, 80V ,X7R,Ceramic capacitor (1210) 150µF,20%,80V,ELECT,13mm 1µF 10%, 16V ,X7R,Ceramic capacitor (0603) 10µF 10%, 10V ,X7R,Ceramic capacitor (0805) 15000pF,10%,50V,X7R,0402,Ceramic capacitor(0402) 0.47µF,10%,10V,X7R, Ceramic capacitor(0402) 0.1µF,10%,50V,X7R, Ceramic capacitor(0402) 180µF 20%, 6.3V ,X7R,Ceramic capacitor (1210) 10µF 10%, 10V ,X7R,Ceramic capacitor (1210) 1000pF,10%,100V,X7R,0402,Ceramic capacitor(0402) 10nF,10%,50V,X7R,0402,Ceramic capacitor(0402) 120pF,2%,50V,X7R,0402,Ceramic capacitor(0402) Diode PIV=100V; IF=1A 3-pin header (36-pin header 0.1” centers ) INDUCTOR, 3.3µH, 19.4A N-CHANNEL POWER MOSFET(LFPAK) PD-(45W); I-(25A); 17 V-(60V) N-CHANNEL POWER MOSFET(LFPAK) D-(65W); I-(45A); V18 (60V) Quantity 2 2 1 1 1 1 1 1 1 2 1 1 1 1 1 1 Designator C1,C2 C3,C4 C5 C6 C7 C8 C9 C10 C11 C13,C14 C15 C18 C19 D1 JU1,JU3,JU4 L1 1 Q1 RENESAS RJK0651DPB-00#J5 1 Q2 RENESAS RJK0653DPB-00#J5 19 RES+,0Ω,1%,0402 8 20 21 22 23 24 25 RES+,2.2Ω,1%,0402 RES+,0.005Ω,1%,1.5W,2010 RES+,7.5KΩ OHM,1%,0402 RES+,100KΩ OHM,1%,0402 RES+,95.3KΩ OHM,1%,0402 RES+,17.8KΩ OHM,1%,0402 Buck Controller MAX17557ATP+ 1 1 1 1 1 1 R1, R4, R7, R9, R12-R14, R19 R2 R8 R17 R18 R20 R21 1 U1 26 www.maximintegrated.com Part Number MURATA GRM188R72A104KA35 MURATA GRM32ER71K475ME14 PANASONIC EEV-FK1K151Q MURATA GRM188R71C105KA12 MURATA GGRM21BR71A106KE51 MURATA GRM155R71H153KA12 MURATA GRM155R61A474KE15 MURATA GRM155R71H104KE14 PANASONIC EEFSE0J181R MURATA GRM32DR71A106KA01 MURATA GRM155R72A102KA01 MURATA GRM155R71H103JA88 MURATA GRM1555C1H121GA01 DIODES INCORPORATED DFLS1100-7 Sullins: PEC03SAAN COILCRAFT XAL7070-332ME MAX17557ATP+ Maxim Integrated │ 6 VIN EN R5 OPEN 1 JU4 R6 OPEN A OPEN D1 2 3 C JU1 7.5K R17 JU3 1 2 3 R3 1 2 3 OPEN 120PF C19 C18 0.01UF VCCINT 1000PF C15 VCCINT C8 0.015UF COMP 5 SGND TEST2 4 EN GND 20 ILIMSEL 8 TEST1 RT SS 3 2 7 1 FB PGOOD CSN CSP PGND DL LX BST DH VCCINT IN VCCEXT PGND MAX17557 U1 6 10 19 16 9 12 15 11 13 14 17 18 0 R7 C6 1UF 2.2 R2 VOUT C1 0 R9 C9 0.47UF D2 C16 R18 0 4 C2 0.1UF D G S VCCINT PGOOD C Q2 R4 100K OPEN A VCCINT 10UF C7 VCCINT 0.1UF 0 1000PF C17 Q1 OPEN 4 C3 4.7UF VIN 4.7UF C4 G S D 5 1 L1 3.3UH R16 OPEN 0 R11 OPEN R10 R14 1 C5 150UF + 2 OPEN 1 2 3 VCCINT EP 21 5 1 2 3 2 R12 PGND VIN R13 0.005 R8 C10 0.1UF C11 180UF 1 + 2 C12 OPEN 1 + 2 VIN 0 www.maximintegrated.com C13 10UF 10UF C14 VOUT PGND R21 17.8K 95.3K R20 VOUT 5V@10A R19 0 0 R1 MAX17557 5V Output Evaluation Kit Evaluates: MAX17557 5V Output-Voltage Application MAX17557 EV System Schematic Maxim Integrated │ 7 Evaluates: MAX17557 5V Output-Voltage Application MAX17557 5V Output Evaluation Kit MAX17557 EV System PCB Layout 1” 1” MAX17557 EV Kit Silk Top MAX17557 EV Kit Top 1” MAX17557 EV Kit L2-GND www.maximintegrated.com Maxim Integrated │ 8 Evaluates: MAX17557 5V Output-Voltage Application MAX17557 5V Output Evaluation Kit MAX17557 EV System PCB Layout (continued) 1” MAX17557 EV Kit L3-GND www.maximintegrated.com 1” MAX17557 EV Kit Bottom Maxim Integrated │ 9 Evaluates: MAX17557 5V Output-Voltage Application MAX17557 5V Output Evaluation Kit Revision History REVISION NUMBER REVISION DATE 0 8/17 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. © 2017 Maxim Integrated Products, Inc. │ 10