19-2053; Rev 1; 4/02 MAX5015 Evaluation Kit The MAX5015 evaluation kit (EV kit) is a fully assembled and tested circuit board that contains a 50W forward converter in the industry standard half-brick footprint. The circuit is configured for a +5.0V output voltage and provides up to 10A of current. Power for the circuit can be provided from either a +36V to +72V or -36V to -72V DC source. High efficiency of 86% is achieved at 5A using a single transistor, forward converter topology providing output power up to 50W. The surface mount transformer provides galvanic isolation and has a reset winding to recover magnetic energy. Galvanic isolation up to 1500V is achieved by an optocoupler and surfacemount transformer. Operation at 280kHz allows the use of small magnetics and output capacitors. Warning: The MAX5015 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. Component Suppliers SUPPLIER Central Semiconductor PHONE FAX 516-435-1110 516-435-1824 Coiltronics 561-752-5000 561-742-0134 Dale-Vishay 402-564-3131 402-563-6418 General Semiconductor 631-847-3000 631-847-3236 International Rectifier 310-322-3331 310-322-3332 Murata 814-237-1431 814-238-0490 Sanyo USA 619-661-6835 619-661-1055 Taiyo Yuden 408-573-4150 408-573-4159 TDK 847-803-6100 847-390-4405 Features ♦ +36V to +72V or -36V to -72V Input Range ♦ +5V Output at 10A ♦ VOUT Regulation better than 0.1% over Line and Load ♦ 86% Efficiency at 48V Input and 5V/5A Output ♦ Half-Brick Module Footprint and Pinout ♦ Short-Circuit Protection ♦ 275kHz Switching Frequency ♦ Designed for 1500V Isolation ♦ Soft-Start ♦ Fully Assembled and Tested ♦ Remote ON/OFF ♦ Remote Sense Ordering Information PART TEMP. RANGE MAX5015EVKIT 0°C to +70°C IC PACKAGE SO-8 Component List DESIGNATION QTY DESCRIPTION C1, C15 2 0.1µF, 10%, 50V, X7R ceramic capacitors (0805) Taiyo Yuden UMK212BJ104KG C2 1 0.01µF, 10%, 50V, X7R ceramic capacitor (0805) C3 0 Not installed (0805) C4, C5, C6 3 0.68µF, 100V, X7R ceramic capacitors (1812) TDK C4532X7R2A684K C7, C13, C14 3 560µF, 6.3V electrolytic capacitors (8 x 11.5) Sanyo 6MV560WX C8 1 0.047µF, 10%, 50V, X7R ceramic capacitor (0805) Taiyo Yuden UMK212BJ473KG C9 1 10µF, 20%, 16V, X5R ceramic capacitor (1210) Taiyo Yuden EMK325BJ106MN Component List continued on next page. Note: Please indicate that you are using the MAX5015 when contacting these component suppliers. ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 Evaluates: MAX5015 General Description Evaluates: MAX5015 MAX5015 Evaluation Kit Component List (continued) DESIGNATION C10 C11 C12 C16 1 1 1 1 DESCRIPTION 0.1µF, 10%, 16V, X7R ceramic capacitor (0603) Taiyo Yuden EMK107BJ104KA 0.33µF, 10%, 35V, X7R ceramic capacitor (0805) Taiyo Yuden GMK212BJ334KG 0.001µF, 200V, X7R ceramic capacitor (0603) Murata GRM39-X7R102K200 0.0047µF, 250VAC, X7R ceramic capacitor (3045) Murata GHM3045-X7R472K-GC DESIGNATION QTY R5 1 240kΩ ±5% resistor (0805) DESCRIPTION R6 1 0.1Ω ±1% power resistor (1206) Dale Electronics, Inc. WSL-1206 0.1Ω ±1% R7 1 1Ω ±5% resistor (0805) R8 1 499Ω ±1% resistor (0805) R9 1 150Ω ±5% resistor (0805) R11 1 25.5kΩ ±1% resistor (0805) R12 1 8.25kΩ ±1% resistor (0805) R13 1 4.75kΩ ±1% resistor (0805) R15 1 3.32kΩ ±1% resistor (0805) R16, R17 2 51Ω ±5% resistors (0805) C17 1 0.022µF, 10%, 25V, X7R ceramic capacitor (0603) T1 1 D1 0 Not installed 15V, 150mW zener diode (S-mini) 170µH 1:0.857: 0.357:0.357 turn transformer (12-pin Gull Wing) Coiltronics CTX03-14856 U1 1 MAX5015ESA (8 SO) D2 0 Not installed 3V 150mW zener diode (S-mini) U2 1 D3 1 80V, 100mA Schottky diode (S-mini) 70V 100% to 200% CTR phototransistor (8-pin SO) QT Optoelectronics MOC207 U3 1 1.24V precision shunt regulator (SOT23) Texas Instruments TLV431AIDBV None 1 Aluminum heatsink plate Vista Industrial Products 5015 None 2 Nylon spacers, 1/4 x 5/8 nylon None 2 Nylon screws, 4-40 x 1/4 None 2 Nylon screws, 4-40 x 1/2 None 2 Nylon screws, 6-32 x 3/8 None 2 TO-220AB Mica thermal insulating pads None 1 MAX5015 PC board None 1 MAX5015 data sheet None 1 MAX5015 EV kit data sheet D4 D5 L1 N1 Q1 2 QTY 1 1 1 1 0 40V, 20A Schottky diode (TO-220AB) General Semiconductor SBL2040CT 250V, 250mA high-voltage switching diode (SOD-123) Central Semiconductor CMHD2003 4.7µH, 21.5A inductor Coiltronics, HC2-4R7 200V, 18A N-channel MOSFET (TO-220AB) International Rectifier IRF640N Not installed NPN transistor (SOT23) R1, R10 0 Not installed (0805) R3 1 20Ω ±5% resistor (1206) _______________________________________________________________________________________ MAX5015 Evaluation Kit The MAX5015 EV kit is fully assembled and tested. Follow these steps to verify board operation. Do not turn on the power supply until all connections are completed. Output 1) Connect a jumper wire from the VOUT pin to the +SENSE pin. 2) Connect a jumper wire from the SGND pin to the -SENSE pin. 3) Connect a voltmeter to the VOUT pin and SGND. 4) Connect a +36V to +72V power supply to the VIN+ pin. Do not exceed 100V input voltage. Connect the power supply’s ground to the VIN- pin. Shutdown Mode (Remote Control Method) The MAX5015 EV kit features a pin to remotely shutdown the forward converter. An open-collector/drain transistor or relay contact must be connected to the SHDN and VIN- pins of the EV kit. Table 1 lists the options. Table 1. Shutdown Pin Function (Remote Control) SHDN PIN Open Pull low MAX5015 OUTPUT MAX5015 Enabled, VOUT = +5.0V Shutdown mode, VOUT = 0V 5) Turn on the power supply above +36V and verify that VOUT provides +5V at the voltmeter. For instructions on selecting the feedback resistors for other output voltages, refer to the Evaluating other Output Voltages section in this document. Detailed Description The MAX5015 EV kit is a 50W forward converter which provides +5.0V and up to 10A at the output. The circuit can be powered from a +36V to +72V or a -36V to -72V DC source. The user must supply at least 220µF of bulk storage capacitor at the input terminals (VIN+, VIN-). The capacitor should be rated for 100V and be able to carry 1.5A of ripple current. The 50W forward converter achieves high efficiency by using a single transistor topology. Current limiting protects the converter against short circuits at the output. A current sense resistor (R6) senses the current through the primary of the transformer (T1) and the switching transistor (N1) and turns off the transistor when the trip level of 500mV is reached. The surfacemount transformer features a reset winding that, along with diode (D5), recovers the magnetic energy stored in the core and feeds it back to the input (VIN+). The transformer provides galvanic isolation up to 1500V. Shunt regulator (U3) along with feedback resistors (R11, R12) provide voltage feedback to the primary side through optocoupler (U2). Remote output voltage sensing is provided by the +SENSE and -SENSE for accurate output voltage regulation across the load. The softstart allows the output voltage to slowly ramp up in a controlled manner within 20ms. The MAX5015 controller switches at a fixed 275kHz frequency, and the duty cycle is varied to control energy transfer to the output. Evaluating Other Output Voltages, Current Limits, and Soft-Starts VOUT Output Voltage The MAX5015 EV kit’s output (VOUT) is set to +5.0V by feedback resistors (R11, R12). To generate output voltages other than +5.0V (+3.2V to +5.0V), select different voltage-divider resistors (R11, R12). Resistor R11 is typically chosen to be less than 25kΩ. Using the desired output voltage, resistor R12 is then found by the following equation: R12 = [R11 / ((VOUT / VREF) - 1)] where VREF = 1.24V The maximum output current should be limited to less than 10A. The usable output voltage range for the EV kit is +3.2V to +5.0V. Additionally, ICs U2, U3, and resistor R9 limit the minimum output voltage (VOUT) to +3.2V. Current Limiting The EV kit features current limiting for the transformer primary current. The MAX5015 IC turns off the switching MOSFET (N1) when the voltage at the CS pin of the device reaches 465mV. A current sense resistor (R6, 0.1Ω) limits the peak primary current to 4.65A (465mV / 0.1Ω = 4.65A). This will limit short-circuit current on the secondary output (VOUT) to 13A typically. To evaluate lower current limits, the current sense resistor (R6) must _______________________________________________________________________________________ 3 Evaluates: MAX5015 Shutdown Quick Start be replaced with a surface-mount resistor (1206 size) as determined by the following equation: R6 = VSENSE / ((NS / NP) x (1.2 x IOUTMAX)) where VSENSE = 0.5V, NS = 5, NP = 14, and IOUTMAX = maximum DC output current (10A as configured). Soft-Start The MAX5015 EV kit limits the ramp time to full current limit and duty cycle with a soft-start feature. Capacitor C2 (0.01µF), sets the ramp time to 20ms. To evaluate other soft-start ramp times replace capacitor C2 with another surface mount capacitor (0805 size) as determined by the following equation: C2 (µF) = soft-start time (s) / (0.45s/µF) 1V/div 0 4ms/div Figure 2. Output Voltage Transient at Power-Up. VIN+ = 48V, IOUT = 5A Forward Converter Waveforms EFFICIENCY (%) vs. OUTPUT CURRENT (A) 90.0 80.0 70.0 EFFICIENCY (%) Evaluates: MAX5015 MAX5015 Evaluation Kit 60.0 20V/div 50.0 40.0 0 30.0 20.0 1µs/div 10.0 0 0 2 4 6 8 10 12 14 Figure 3. MOSFET N1, Drain-Source Voltage Waveform, VIN+ = 48V OUTPUT CURRENT (A) Figure 1. Efficiency vs. Output Current. VIN+ = 48V 4 _______________________________________________________________________________________ MAX5015 Evaluation Kit VIN R1 OPEN 3 4 2 3 D3 SHORT COLLECTION TO EMITTER VIN T1 D5 1 Q1 VDD 5 6 1 C4 0.68µF 1 8 C9 10µF C1 0.1µF VCC V+ NDRV VCC GND SS/SHDN 2 VDD C11 0.33µF VDD C6 0.68µF 7 6 N1 1 2 1 C12 0.001µF 200V D4 L1 4.7µH VOUT C7 560µF 6.3V C13 560µF 6.3V C14 560µF 6.3V C15 0.1µF SGND C16 0.0047µF 250VAC R8 499Ω 1% CS 4 C2 0.01µF CS 9 8 2 3 U1 OPTO 3 2 R7 1Ω SHDN R6 0.1Ω 1% MAX5015 3 5 C3 OPEN R16 51Ω CS VOUT R9 150Ω R13 4.75kΩ 1% R15 3.32kΩ 1% C5 0.68µF 12 11 R3 20Ω C8 0.047µF VIN+ VIN- Evaluates: MAX5015 D1 OPEN +SENSE 6 R10 SHORT D2 5 OPEN C17 0.022µF R5 240kΩ U2 7 1 C10 0.1µF 2 3 U3 4 5 R11 25.5kΩ 1% R17 51Ω R12 8.35kΩ 1% -SENSE Figure 4. MAX5015 EV Kit Schematic _______________________________________________________________________________________ 5 Evaluates: MAX5015 MAX5015 Evaluation Kit 1.0" Figure 5. MAX5015 EV Kit Component Placement Guide— Component Side 1.0" Figure 7. MAX5015 EV Kit PC Board Layout—Inner Layer, Ground Plane 6 1.0" Figure 6. MAX5015 EV Kit PC Board Layout—Component Side 1.0" Figure 8. MAX5015 EV Kit PC Board Layout—Inner Layer, Power Plane _______________________________________________________________________________________ MAX5015 Evaluation Kit Evaluates: MAX5015 1.0" 1.0" Figure 9. MAX5015 EV Kit PC Board Layout—Solder Side Figure 10. MAX5015 EV Kit Component Placement Guide— Solder Side 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 _____________________ 7 © 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.