MAX17500AEVKIT

19-5764; Rev 0; 2/11 MAX17500A Evaluation Kit Evaluates: MAX17500A General Description Features The MAX17500A evaluation kit (EV kit) is a fully assembled and tested circuit board that contains a 9W flyback DC-DC converter. The circuit is configured for +5V and +15V output voltages and provides up to 1.5A and 100mA of current at each respective output. Power for the circuit can be provided from either a +36V to +72V or -36V to -72V DC source. S +36V to +72V or -36V to -72V DC Input Range High efficiency up to 81% is achieved using a flyback DC-DC converter topology. The surface-mount transformer provides up to +1500V galvanic isolation for both outputs. Low cost is achieved through the use of primary-side regulation, while undervoltage lockout (UVLO) and digital soft-start provide for a robust 9W isolated power supply. S 81% Efficiency at +48V Input and Full Load Operation at 350kHz allows the use of small magnetics and output capacitors. Warning: The EV kit is designed to operate with high voltages. Dangerous voltages are present on this EV kit and on equipment connected to it. Users who power up this EV kit or power the sources connected to it must be careful to follow safety procedures appropriate to working with high-voltage electrical equipment. Under severe fault or failure conditions this EV kit may dissipate large amounts of power, which could result in the mechanical ejection of a component or of component debris at high velocity. Operate this kit with care to avoid possible personal injury. S Isolated Outputs VOUT1: +5V Provides Up to 1.5A VOUT2: +15V Provides Up to 100mA S ±5% (typ) Load Regulation for the +5V Output Set Point (150mA to 1.5A) S Cycle-by-Cycle Current Limit S 350kHz Switching Frequency S Digital Soft-Start S High-Accuracy UVLO S UVLO Open-Drain Flag Output S Designed for +1500V Isolation with Primary-Side Regulation S Low-Cost Flyback Design S Proven PCB Layout S Fully Assembled and Tested Ordering Information appears at end of data sheet. Component List DESIGNATION QTY DESCRIPTION DESIGNATION QTY C1, C2 2 1FF Q10%, 100V X7R ceramic capacitors (1812) TDK C4532X7R2A105K C3 1 68FF, 6.3V electrolytic capacitor (V) KEMET A700V686M006ATE028 C4 1 C5 C6 DESCRIPTION C7, C11 2 0.22FF Q10%, 50V X7R ceramic capacitors (0805) Murata GRM21BR71H224KA01B C8, C10, C19 0 Not installed, ceramic capacitors (0603) 22FF Q20%, 6.3V X5R ceramic capacitor (1206) TDK C3216X5R0J226M C9 1 100pF Q2%, 50V C0G ceramic capacitor (0603) Murata GRM1885C1H101G 1 47FF, 25V electrolytic capacitor (6.3mm x 5.8mm) Panasonic EEVFK1E470P C12 1 15FF Q10%, 35V tantalum capacitor (D) KEMET T491D156K035AS 1 0.0047FF Q10%, 250V AC X7R ceramic capacitor (1825) Murata GA355DR7GC472KY02L C13 1 1FF Q10%, 16V X7R ceramic capacitor (0805) TDK C2012X7R1C105KT __________________________________________________________________ Maxim Integrated Products   1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. MAX17500A Evaluation Kit Evaluates: MAX17500A Component List (continued) DESIGNATION QTY C14 1 C15 C16 C17 C18 D1 D2 D3 DESCRIPTION 3900pF Q10%, 50V X7R ceramic capacitor (0603) Murata GRM188R71H392K DESIGNATION QTY DESCRIPTION D8 1 40V, 0.5A Schottky diode (SOT23) Zetex ZHCS500 JU1 1 2-pin header L1 1 3A ferrite-bead inductor (1806) Fair-Rite 2518066007Y3 1 1FF Q10%, 25V X7R ceramic capacitor (0805) TDK C2012X7R1E105KT L2 1 100mA ferrite-bead inductor (0805) Fair-Rite 2508051027Y0 1 1FF Q10%, 50V X7R ceramic capacitor (1206) Murata GRM31MR71H105K N1 1 Not installed, ceramic capacitor (0805) 200V, 1.2A n-channel MOSFET (8 SO) IR IRF7464PBF R1 1 22.6kI Q1% resistor (0603) R2 1 2.49kI Q1% resistor (0603) R3 1 1.37MI Q1% resistor (0805) R4 1 51.1kI Q1% resistor (0805) R5 1 0.600I Q1% power resistor (1206) IRC LRC-LR1206LF-01-R600-F R6 1 33kI Q5% resistor (1206) 0 1 0.1FF Q10%, 25V X7R ceramic capacitor (0603) Murata GRM188R71E104K 1 40V, 10A Schottky diode (PowerDIM 5) Diodes Inc. PDS1040-13 1 0 200V, 1.5A super-fast diode (SMD) Vishay BYG20D R7, R12 2 1.2kI Q5% resistors (1206) R8 0 Not installed, resistor (1206) Not installed, 250V, 250mA highvoltage switching diode (SOD123) Central Semi CMHD2003 recommended R9 1 75kI Q1% resistor (0603) R10 1 4.7I Q5% resistor (0805) R11 1 100I Q5% resistor (0603) R13 1 10kI Q5% resistor (0805) R14 1 14.3kI Q1% resistor (0805) R15 1 750I Q5% resistor (0603) D4 1 5.6V, 0.5W zener diode (SOD123) Diodes Inc. BZT52C5V6 D5 1 18V, 0.5W zener diode (SOD123) Diodes Inc. BZT52C18 T1 1 D6 1 75V, 250mA high-speed diode (SOT23) Central Semi CMPD914 35FH, 10W, 1:0.536:0.214:0.429 turn 350kHz transformer (10 gull wing) Cooper Bussmann CTX03-17492-R U1 1 Current-mode PWM controller (10 FMAXM) Maxim MAX17500AEUB+ — 4 Rubber bumpers — 1 Shunt (JU1) — 1 PCB: MAX17500A EVALUATION KIT D7 0 Not installed, 14V, 250mW zener diode (SOD323) Central Semi CMDZ5244B recommended PowerDI is a registered trademark of Diodes Incorporated. µMAX is a registered trademark of Maxim Integrated Products, Inc. __________________________________________________________________ Maxim Integrated Products   2 MAX17500A Evaluation Kit Evaluates: MAX17500A Componets Suppliers SUPPLIER PHONE WEBSITE Central Semiconductor Corp. 631-435-1110 www.centralsemi.com Cooper Bussmann 916-941-1117 www.cooperet.com Diodes Incorporated 805-446-4800 www.diodes.com Fair-Rite Products Corp. 845-895-2055 www.fair-rite.com International Rectifier 310-322-3331 www.irf.com IRC, Inc. 361-992-7900 www.irctt.com KEMET Corp. 864-963-6300 www.kemet.com Murata Electronics North America, Inc. 770-436-1300 www.murata-northamerica.com Panasonic Corp. 800-344-2112 www.panasonic.com TDK Corp. 847-803-6100 www.component.tdk.com Vishay 402-563-6866 www.vishay.com Zetex Semiconductor (now a Division of Diodes Incorporated) 805-446-4800 www.diodes.com Note: Indicate that you are using the MAX17500A when contacting these component suppliers. Quick Start • MAX17500A EV kit Required Equipment • +36V to +72V power supply capable of providing up to 1A • Two voltmeters • 22µF, +100V bulk-storage capacitor to be connected to the input terminals on the EV kit 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) Connect the first voltmeter to the VOUT1 and SGND PCB pads. For instructions on selecting the feedback resistors for other output voltages, see the Evaluating Other Output Voltages, Current Limits, and Undervoltage Lockouts section. Detailed Description of Hardware The MAX17500A EV kit is a fully assembled and tested circuit board that contains a 9W isolated flyback DC-DC converter that provides a +5V and +15V output. The +5V output (VOUT1) provides up to 1.5A and the +15V output (VOUT2) provides up to 100mA. The circuit can be powered from either a +36V to +72V or -36V to -72V DC source. The user must supply at least 22µF of bulkstorage capacitance at the input terminals (+VIN, -VIN). The capacitor should be rated for +100V and be able to carry approximately 200mA of ripple current. 7) Verify that the voltmeter at VOUT2 reads approximately +15V. The flyback DC-DC converter achieves up to 81% efficiency. The single-transistor topology and primary-side regulation provide for a low-cost design by eliminating the need for an optocoupler and shunt reference on the secondary side. The EV kit provides cycle-by-cycle, primary-side current-limit protection. Current-sense resistor R5 senses the current through the transformer’s (T1) primary winding, switching transistor (N1), and turns off the transistor when the trip level of +1V is reached. The surface-mount transformer provides galvanic isolation up to +1500V for both outputs. The EV kit features PCB pads for an RCD snubber network (R8, C10, D3) to minimize leakage energy ringing and clamp the voltage at the drain of MOSFET N1 during switching (with most MOSFETs this snubber circuit can be eliminated). The maximum current for each output should be limited to less than 1.5A for VOUT1 and 100mA for VOUT2. Primary-side regulation through feedback resistors R1 and R2, rectifier D6, and transformer T1 tertiary 2) Connect the second voltmeter to the VOUT2 and SGND PCB pads. 3) Connect a 750mA load to VOUT1 and a 50mA load to VOUT2. 4) Verify that a shunt is not installed on jumper JU1 (SHDN). 5) Connect the power supply’s positive terminal to the +VIN PCB pad. Connect the power supply’s ground to the -VIN PCB pad. 6) Turn on the power supply above +36V and verify that the voltmeter at VOUT1 reads approximately +5V. __________________________________________________________________ Maxim Integrated Products   3 MAX17500A Evaluation Kit Evaluates: MAX17500A windings provide Q5% regulation for the +5V output set point. Resistors R7 and R12 are adjusted to preload the tertiary winding for the desired +5V output set point and regulation. UVLO provides controlled turn-on and shutdown during brownouts, power-up, or power-down. The UVLO settings can be changed by replacing resistor R3. Startup resistor R6 and reservoir capacitor C16 enable the device to start up within approximately 37ms. The digital soft-start allows the output voltage to slowly ramp up in a controlled manner within 6ms. The device controller switches at a fixed 350kHz frequency and is set by resistor-capacitor networks R14, R15/C18, and C19. The switching duty cycle is varied to control energy transfer to the isolated outputs. The maximum duty cycle is 50% for the EV kit’s discontinuous current-mode flyback design. Shutdown Mode (Jumper and Remote-Control Methods) The EV kit features two methods to shut down the flyback DC-DC converter. Jumper JU1 can be used to shut down the flyback DC-DC converter. An alternate method, remote-control shutdown, can be done with a user-supplied open-collector/drain transistor or relay contact connected to the SHDN and -VIN PCB pads on the EV kit. Table 1 lists the shutdown mode. Evaluating Other Voltages, Current Limits, and Undervoltage Lockouts VOUT1 and VOUT2 Output Voltages The EV kit’s outputs (VOUT1 and VOUT2) are set to +5V and +15V, respectively, by the T1 transformer tertiary windings, the transformer’s respective secondary output windings, and the resistor-divider R1 and R2. To generate scaled output voltages other than +5V (+4.2V to +6.8V) and +15V (+12.3V to +20.2V), select different voltage-divider resistors (R1, R2). Resistor R2 is typically chosen to be less than 5kI. When evaluating other output voltages, verify that the secondary outputs’ components affected by increased voltage are rated for the appropriate voltage. Components C3, C4, C13, and D4 of VOUT1 and components C5, C15, and D5 should have their respective voltage rating evaluated. Using the desired scaled output voltages, resistor R1 is then found by the following equation: R1 = [[{(VOUT1 - VVD1) x NT/N1} - VVD6]/VFB -1] x R2 where: VOUT1 is the +5V output. NT = 15 is the transformer’s tertiary turns. N1 = 6 is the transformer’s secondary VOUT1, +5V output turns. VFB = +1.23V is the device reference voltage. VVD6 = +1V is the circuit’s tertiary winding, high-speed diode D6 forward-voltage drop. VVD1 = +0.45V (typ) is the circuit’s secondary-side Schottky diode D1 forward-voltage drop at 1.5A. Both output voltages are scaled up or down since the respective transformer’s secondary output turns set the actual voltage. Additionally, the maximum current for each output should be limited to less than 1.5A for VOUT1 and 100mA for VOUT2. Current Limiting The EV kit features current limiting for the transformer’s primary current. The device turns off switching MOSFET N1 when the voltage at the device’s CS pin reaches +1V. Current-sense resistor R5 (0.6I) limits the transformer peak primary current to 1.67A (+1V/0.6I = 1.67A). This limits the average short-circuit current on the secondary outputs typically to 1.42A (average with IOUT2 = 100mA) and 0.52A (average with IOUT1 = 1.5A) for VOUT1 and VOUT2, respectively. To evaluate a lower current limit, current-sense resistor R5 must be replaced with a different surface-mount resistor (1206 size), as determined by the following equation. When considering the transformer’s primary input current: R5 = (VSENSE/IPRIMARY) where VSENSE = +1V and IPRIMARY is the transformer’s maximum primary current. Undervoltage Lockout (UVLO) The EV kit features an accurate UVLO circuit that prevents operation below the programmed input-supply start voltage. Resistors R3 and R4 set the voltage at the device’s UVLO/EN pin, which determines the UVLO wake-up and shutdown levels of +1.23V (typ) and +1.17V (typ), respectively. To evaluate other wake-up and shutdown levels, replace R3 with another surface-mount Table 1. Jumper JU1 Shutdown Mode SHUNT POSITION DEVICE UVLO/EN PIN DEVICE OUTPUT Not installed UVLO resistors R3 and R4 determine startup voltage Device enabled Installed Pulled low to -VIN Shutdown mode __________________________________________________________________ Maxim Integrated Products   4 MAX17500A Evaluation Kit Evaluates: MAX17500A resistor (0805 size). Refer to the Undervoltage Lockout section in the MAX17499/MAX17500 IC data sheet for instructions on selecting resistor R3, as determined by the following equation: R3 = ((VIN - VUVLO)/VUVLO) x R4 where VIN is the +36V to +72V supply voltage applied between the +VIN and -VIN PCB pads on the EV kit and VUVLO = +1.23V (typ). UVLO Flag (UFLG and FLG_PULL) The EV kit features an open-drain UVLO flag output at the UFLG PCB pad. The UFLG signal can be used to indicate that a UVLO condition has occurred. A voltage source of up to +25V can be connected to the PCB’s FLG_PULL PCB pad, which, along with resistor R13, pulls up the UFLG signal. Refer to the UVLO Flag (UFLG) section in the MAX17499/MAX17500 IC data sheet for instructions and additional information on using the device’s UFLG pin. Flyback Converter Waveforms EFFICIENCY vs. OUTPUT CURRENT 90 OUTPUT TURN-0N VOLTAGE TRANSIENT VOUT2 = +15V, 100mA 80 VOUT1 2V/div EFFICIENCY (%) 70 60 50 VOUT2 = +15V, 25mA VOUT2 40 30 5V/div 20 10 0 0 0.3 0.6 0.9 1.2 2ms 1.5 IOUT1 (A) Figure 1. Efficiency vs. Output Current IOUT1 (+VIN = +48V) Figure 2. Output-Voltage Transient at Power-Up (+VIN = +48V, Channel 1 = VOUT1 (IOUT1 = 150mA), and Channel 2 = VOUT2 (IOUT2 = 25mA)) VOUT1 REGULATION vs. IOUT1 VOUT2 REGULATION vs. IOUT2 18.0 6.0 17.6 5.8 VOUT2 = +15V, 25mA 17.2 5.4 16.8 5.2 16.4 5.0 VOUT2 (V) VOUT1 (V) 5.6 VOUT2 = +15V, 100mA 4.8 VOUT1 = +5V, 150mA 16.0 15.6 4.6 15.2 4.4 14.8 4.2 14.4 VOUT1 = +5V, 1.5A 14.0 4.0 0 0.3 0.6 0.9 1.2 1.5 IOUT1 (A) Figure 3. VOUT1 (+5V) Output-Voltage Regulation 0 0.02 0.04 0.06 0.08 0.10 IOUT2 (A) Figure 4. VOUT2 (+15V) Output-Voltage Regulation __________________________________________________________________ Maxim Integrated Products   5 MAX17500A Evaluation Kit Evaluates: MAX17500A Figure 5. MAX17500A EV Kit Schematic __________________________________________________________________ Maxim Integrated Products   6 MAX17500A Evaluation Kit Evaluates: MAX17500A 1.0” Figure 6. MAX17500A EV Kit Component Placement Guide— Component Side 1.0” Figure 7. MAX17500A EV Kit PCB Layout—Component Side 1.0” Figure 8. MAX17500A EV Kit PCB Layout—Solder Side __________________________________________________________________ Maxim Integrated Products   7 MAX17500A Evaluation Kit Evaluates: MAX17500A Ordering Information PART TYPE MAX17500AEVKIT EV Kit __________________________________________________________________ Maxim Integrated Products   8 MAX17500A Evaluation Kit Evaluates: MAX17500A Revision History REVISION NUMBER REVISION DATE 0 2/11 DESCRIPTION Initial release PAGES CHANGED — Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ©  2011 Maxim Integrated Products 9 Maxim is a registered trademark of Maxim Integrated Products, Inc.