19-3513; Rev 0; 11/04 MAX5069A Evaluation Kit Operation at 500kHz allows the use of small magnetics and output capacitors. A SYNC input is featured to ease synchronization to an external clock. The EV kit provides cycle-by-cycle current-limit protection. Additional steadystate fault protection is provided by the integrating fault protection that reduces average dissipated power during continuous overload conditions. The MAX5069A also has a programmable input undervoltage lockout (UVLO) for protection during brownout conditions. The EV kit may be used to evaluate other versions of the MAX5069. Warning: The MAX5069A 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. Features ♦ 120W High-Efficiency, Isolated, Push-Pull DC-DC Converter ♦ ±36V to ±72V Input Range ♦ +12V Output at 10A ♦ VOUT Regulation Better than 0.1% Over Line and Load ♦ 91% Efficiency at 48V and 10A ♦ Programmable Input UVLO ♦ Cycle-by-Cycle Current-Limit Protection ♦ Programmable Integrating Fault Protection ♦ 500kHz Oscillator Frequency ♦ External Clock SYNC Input ♦ Fully Assembled and Tested Ordering Information PART TEMP RANGE IC PACKAGE MAX5069AEVKIT 0°C to +50°C* 16 TSSOP *With 200LFM airflow. Component List DESIGNATION QTY DESCRIPTION C1 1 0.1µF ±10%, 16V X7R ceramic capacitor (0603) Murata GRM39X7R104K016AD C2, C3, C4 3 1µF ±10%, 100V X7R ceramic capacitors (1210) AVX 1210C105KAT9A C5, C6, C7, C18, C19, C20 6 47µF ±10%, 16V X5R ceramic capacitors (1210) Murata GRM32ER61C476K C8 1 0.1µF ±10%, 50V X7R ceramic capacitor (0603) Murata GRM188R71H104K C9 1 10µF ±20%, 35V, low-impedance electrolytic capacitor (5mm x 6mm) Sanyo 35CV10KX C10 1 12pF ±5%, 50V C0G ceramic capacitor (0603) Murata GRM1885C1H120J ________________________________________________________________ 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: MAX5069A General Description The MAX5069A evaluation kit (EV kit) is a fully assembled and tested circuit board that contains a high-efficiency, 120W isolated push-pull DC-DC converter. The circuit is configured for a +12V output voltage and provides up to 10A of output current. The circuit can be powered from either a +36V to +72V or -36V to -72V DC source, as used in the telecom/datacom markets, industrial environments, or in automotive 42V power systems. High efficiency up to 91% is achieved at 10A while using two n-channel primary-side MOSFETs switching at up to 90% combined duty cycle. On the secondary-side, reduced output-voltage ripple and high efficiency is achieved through full-wave rectification from a centertapped planar transformer. Galvanic isolation up to 500V is achieved by an optocoupler and the planar surfacemount transformer. The optocoupler helps in providing isolated secondary-side regulation. Evaluates: MAX5069A MAX5069A Evaluation Kit Component List (continued) DESIGNATION QTY C11 1 C12 DESIGNATION QTY 0.22µF ±10%, 10V X7R ceramic capacitor (0603) TDK C1608X7R1C224K D3 1 200mA, 75V ultra-high-speed diode (SOT323) Central Semiconductor CMSD2838 1 560pF ±5%, 50V C0G ceramic capacitor (0603) Murata GRM1885C1H561J D4, D5 2 100mA, 80V switching diodes (SOD-323) Diodes Inc. 1N4148WS C13 1 1µF ±10%, 16V X5R ceramic capacitor (0603) TDK C1608X5R1C105K L1 1 4.7µH, 17A inductor Cooper HC2LP-4R7 or Coilcraft D05010P-472HCB C14 1 0.033µF ±10%, 16V X7R ceramic capacitor (0603) Murata GRM188R71E333K L2 1 1000µH, 0.045A inductor Coilcraft DS1608C-105 C15 1 4700pF ±10%, 250VAC X7R ceramic capacitor (2220) Murata GA355DR7GC472K N1, N2 2 200V, 3.2A n-channel MOSFETs (SO-8) Vishay Si7450DP or International Rectifier IRF7492 C16 0 Not installed, ceramic capacitor (0603) R1 1 20.0kΩ ±1% resistor (0603) R2 1 1.05kΩ ±1% resistor (0603) 1 0.015µF ±10%, 50V X7R ceramic capacitor (0603) Murata GRM188R71H153K C17 C21, C22 C23 C24 D1 D2 2 DESCRIPTION 0 1 1 1 1 Not installed, ceramic capacitors (1210) 47µF ±10%, 16V X5R ceramic capacitors (1210) Murata GRM32ER61C476K recommended 0.047µF ±10%, 25V X7R ceramic capacitor (0603) Murata GRM188R71E473K 470pF ±10%, 100V C0G ceramic capacitor (0805) Murata GRM2165C2A471K 60V, 30A Schottky diode (TO220AB) International Rectifier 30CTQ060 or Vishay MBR30H60CT 200mA, 75V, ultra-high-speed diode (SOT323) Central Semiconductor CMSD2836 DESCRIPTION R3 1 200kΩ ±1% resistor (0603) R4 1 24.3kΩ ±1% resistor (0603) R5 1 499kΩ ±1% resistor (0805) R6 1 20.0kΩ ±1% resistor (0805) R7 1 10kΩ ±5% resistor (0805) R8 2 10kΩ ±1% resistor (0603) 1MΩ ±5% resistor (0603) R9 1 R10 1 27kΩ ±5% resistor (1206) R11, R12 2 3Ω ±5% resistors (1206) R13 1 220Ω ±5% resistor (0603) R14 0 Not installed, resistor (2010) R15 1 0.060Ω ±1% resistor (2010) IRC LRC-LR2010-01-R060-F R16 0 Not installed, resistor (0603) R17 1 15kΩ ±5% resistor (0603) R18 1 1kΩ ±1% resistor (0603) R19 0 2.2kΩ ±5% resistor (0603) R20 1 5.1kΩ ±5% resistor (0603) R21 1 10Ω ±5% resistor (1206) _______________________________________________________________________________________ MAX5069A Evaluation Kit DESIGNATION QTY DESCRIPTION QTY VOUT, SGND 2 Uninsulated banana jacks DESCRIPTION Rubber bumpers R22 0 TB1 1 2 points terminal block (0.2in center) None 4 T1 1 180W planar transformer Coilcraft B0860-C None 2 Zinc-plated metal screws, 4-40 x 1/4 None 1 Nylon hex nut 4-40 U1 1 MAX5069AAUE (16-pin TSSOP-EP) None 1 Nylon screw 4-40 x 3/8 1 High CTR optocoupler (ultra-small flat-lead) NEC PS2911-1-M None 1 TO-220 thermally conductive insulating pad None 1 TO-220AB aluminum heatsink (10.4°C/W) 1 0.6V ±0.5% shunt regulator (SOT23-5) Maxim MAX8515AEZK-T None 1 MAX5069 PC board U2 U3 Not installed, resistor (1206) DESIGNATION Component Suppliers SUPPLIER AVX PHONE FAX 843-946-0238 843-626-3123 WEBSITE www.avxcorp.com CEL/NEC; California Eastern Laboratories 408-588-2247 408-588-2213 www.cel.com Central Semiconductor 631-435-1110 631-435-1824 www.centralsemi.com Coilcraft 847-639-6400 847-639-1469 www.coilcraft.com Cooper-Coiltronics 561-752-5000 561-742-1178 www.cooperet.com International Rectifier 310-322-3331 310-726-8721 www.irf.com IRC 361-992-7900 361-992-3377 www.irctt.com Murata 770-436-1300 770-436-3030 www.murata.com Sanyo Electronic Device 619-661-6835 619-661-1055 www.sanyodevice.com TDK 847-803-6100 847-390-4405 — — Vishay www.component.tdk.com www.vishay.com Note: Indicate that you are using the MAX5069A when contacting these component suppliers. Quick Start Required Equipment • • • • 36V to 72V power supply capable of providing up to 6A 20A electronic load e.g., HP 6060B Voltmeter 330µF, 100V bulk storage capacitor to be connected to the input terminals of the EV kit • A fan to provide at least 200LFM airflow for extended operation at 10A The MAX5069A 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. DC-DC Converter Output 1) Connect the electronic load (+) terminal to the VOUT banana jack. Connect the electronic load (-) terminal to the SGND banana jack. 2) Connect a voltmeter to the VOUT and SGND terminals to measure the output voltage. 3) Connect the positive terminal of a 36V to 72V power supply to the +VIN terminal (TB1-1). Connect the power supply’s ground to the -VIN terminal (TB1-2). 4) Turn on the electronic load and set it for “current mode” and up to 5A of current. 5) Turn on the power supply above 36V and verify that the voltmeter reads +12V normally. 6) Verify that the electronic load is drawing the appropriate current. _______________________________________________________________________________________ 3 Evaluates: MAX5069A Component List (continued) Evaluates: MAX5069A MAX5069A Evaluation Kit Detailed Description The MAX5069A EV kit is a 120W, isolated, push-pull DC-DC converter that provides +12V at up to 10A output. The circuit can be powered from a 36V to 72V DC source. The user should supply an additional 330µF bulk storage capacitor between the input terminals (+VIN, -VIN). This capacitor should be rated for 100V and be able to carry approximately 2A of ripple current. Lower ripple-current-rated capacitors should be acceptable for short-term operation The push-pull converter achieves high efficiency by using two external n-channel MOSFETs on the primary side that can switch up to 90% combined duty cycle that results in lower primary RMS currents through the MOSFET switches resulting in improved efficiency. Cycle-by-cycle current limiting prevents the primary current from reaching destructive levels, whereas the fault integration feature provides hiccup fault protection. For a continuous short circuit at the output, the MAX5069’s fault integration feature provides hiccup fault protection. This greatly minimizes destructive temperature rise during persistent overload conditions. Pin 8 of the MAX5069A, capacitor C11, and resistor R9 form the fault integration circuit. Current-sense resistors R14 and R15 sense the current through the primary of transformer T1 and turn off the respective MOSFET (N1 or N2) that is switching when the trip level of 314mV (typ) is reached. The planar surface-mount transformer features a bias winding that, along with diode-pair D2, D3, and inductor L2, provide full-wave rectification for the bias voltage powering the MAX5069A once the input voltage is stable. Upon initial input-voltage application, bootstrap resistor R10 and reservoir capacitor C9 enable the MAX5069A to startup within approximately 200ms. The transformer uses a secondary-side center tap and dual Schottky diode D1 to provide full-wave rectification for reduced output-voltage ripple. When either MOSFET is turned off and the alternate turned on, both D1 diodes are conducting. The transformer provides galvanic isolation up to 500V. Resistor R21 and capacitor C24 form a snubber network that suppresses transient overvoltage ringing at diode D1 caused by transformer T1 leakage inductance and diode D1 junction capacitance. On the transformer’s secondary side, a 0.6V shunt regulator (MAX8515, U3) along with feedback resistors R1 and R2 provide secondary-side voltage feedback through optocoupler U2 to the primary side. The MAX5069A receives the voltage feedback signal on the primary side from biasing resistors R16, R17, R18, and optocoupler U2. 4 The MAX5069A controller’s internal oscillator clock switches at 500kHz and the frequency is programmed by resistor R3. The duty cycle of both MOSFETs is varied to control energy transfer to the output. The MAX5069A EV kit’s maximum duty cycle is 90% as configured. Resistor R4 sets the dead time for both switches and has an impact on the maximum duty cycle. The MAX5069A brownout and input-supply startup UVLO threshold voltage is set by resistors R5 and R6. This prevents the power supply from starting up or operating below the programmed input supply voltage. Test point TP1 is provided to connect an external clock to the SYNC pin on the MAX5069A. The EV kit’s PC board layout is a 4-layer 2oz copper PC board. Evaluating Other Output Voltages, Current Limits, UVLOs VOUT Output Voltage The MAX5069A EV kit’s output (VOUT) is set to +12V by feedback resistors R1 and R2. To generate other output voltages in the vicinity of +12V (from +8V to +15V, limited by the output capacitor and diode D1 voltage rating), select different voltage-divider resistors (R1, R2). Resistor R2 is typically chosen to be less than 2kΩ. Using the desired output voltage, resistor R1 is then found by the following equation: V R1 = R2 OUT − 1 V REF where VREF = 0.6V The maximum output current should be limited to less than 10A. The usable output voltage range for the EV kit is +8V to +15V. Additionally, ICs U3, U2, and resistor R19 limit the minimum output voltage (VOUT) to +2.6V. For voltages outside the above range, a different turns ratio transformer may be required. Current Limiting The EV kit features cycle-by-cycle current limiting of the transformer primary current. Current-sense resistors R14 and R15 sense the current through the primary of transformer T1 and turn off MOSFET N1 or N2 when the trip level of 314mV (typ) is reached. Current-sense resistors R14 and R15 limit the peak primary current to approximately 5.3A (314mV / 0.060Ω ≈ 5.3A). This will limit short-circuit current on the secondary output (VOUT) to 20A typically. To evaluate lower current limits, current-sense resistors R14 and R15 must be replaced with different value surface-mount resistors (2010 size) as determined by the following equation: _______________________________________________________________________________________ MAX5069A Evaluation Kit VSENSE Push-Pull DC-DC Converter NS N × (1.2 × IOUTMAX ) P where R CS = parallel combination of R14 and R15, VSENSE = 0.314V, NS = 2, NP = 5, and IOUTMAX = maximum DC output current (10A or less). Note that some fine-tuning may be required when selecting the currentlimit resistors. Errors are introduced as a result of the MAX5069A IC current-limit propagation delays. Input Undervoltage Lockout (UVLO) The MAX5069A EV kit features a brownout and inputsupply startup UVLO circuit that prevents operation below the programmed input-supply start voltage. Resistors R5 and R6 set the input undervoltage lockout threshold of the EV kit. To evaluate other input UVLO voltages, replace resistor R5 with another surface-mount resistor (0805 size). Using the desired startup voltage, resistor R5 is then found by the following equation: N1 DRAIN VOLTAGE 0V N2 DRAIN VOLTAGE 0V 1µs/div Figure 1. MOSFETs N1 and N2 Drain-Source Voltage Waveforms (50V per Division, 1µs per Division) VINSTARTUP R5 = − 1 × R6 1.231V where VINSTARTUP is the desired startup voltage at which the EV kit starts and resistor R6 is typically in the 20kΩ range. Refer to the MAX5069A/D UVLO Adjustment and Bootstrap Undervoltage Lockout sections of the MAX5069 data sheet for additional information on the UVLO/EN pin of the MAX5069A IC. _______________________________________________________________________________________ 5 Evaluates: MAX5069A RCS = 6 R6 20.0kΩ 1% R5 499kΩ 1% -VIN +VIN C11 0.22µF C14 0.033µF R20 5.1kΩ R8 10kΩ 1% R4 24.3kΩ 1% C10 12pF R3 200kΩ 1% SYNC TB1–2 TB1–1 TB1 8 7 6 5 4 3 2 1 SCOMP R9 1MΩ FLTINT COMP FB UVLO/EN DT U1 REG5 C3 1µF 100V CS AGND PGND NDRVB NDRVA VCC MAX5069A IN SYNC RT C2 1µF 100V 9 10 11 12 13 14 15 VCC C1 0.1µF 16 TP1 R16 OPEN C13 1µF C12 560pF 4 D4 R11 3Ω C9 10µF 35V C4 1µF 100V R22 OPEN R18 1kΩ 1% R17 15kΩ R13 220Ω D5 R12 3Ω SYNC C8 0.1µF R10 27kΩ R7 10kΩ IN L2 1000µH 1 6 3 2 7 8 R14 OPEN 5 4 IN 3 3 1 6 N2 5 D2 D3 3 2 7 8 L R L R N1 1 2 1 2 R15 0.060Ω 1% 10 3 4 2T U2 2T R21 8 10Ω 6 C15 4700pF 250VAC T1 VCC 4 5T 3 5T 2 5 3T 1 C24 470pF 100V 3 2 1 1 D1 2 L1 4.7µH 5 U3 R19 2.2kΩ C16 OPEN C7 47µF 16V C21 OPEN C23 0.047µF GND IN PGND MAX8515 OUT 3 FB C6 47µF 16V C17 0.015µF C5 47µF 16V VOUT 4 1 2 C18 47µF 16V C22 OPEN C19 47µF 16V VOUT VOUT C20 47µF 16V SGND SGND R2 1.05kΩ 1% R1 20.0kΩ 1% VOUT VOUT Evaluates: MAX5069A MAX5069A Evaluation Kit Figure 2. MAX5069A EV Kit Schematic _______________________________________________________________________________________ MAX5069A Evaluation Kit Evaluates: MAX5069A Figure 3. MAX5069A EV Kit Component Placement Guide—Component Side Figure 4. MAX5069A EV Kit PC Board Layout—Component Side _______________________________________________________________________________________ 7 Evaluates: MAX5069A MAX5069A Evaluation Kit Figure 5. MAX5069A EV Kit PC Board Layout—Inner Layer, GND Plane Figure 6. MAX5069A EV Kit PC Board Layout—Inner Layer, VCC Plane 8 _______________________________________________________________________________________ MAX5069A Evaluation Kit Evaluates: MAX5069A Figure 7. MAX5069A EV Kit PC Board Layout—Solder Side Figure 8. MAX5069A 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 _____________________ 9 © 2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.