19-3092; Rev 0; 12/03 MAX5042 Evaluation Kit The MAX5042 evaluation kit (EV kit) is a fully assembled and tested circuit board that contains a high-efficiency, high-power, isolated, hot-pluggable, 40W (with adequate cooling) forward DC-DC converter in the industrystandard half-brick footprint. The circuit is configured for a +5.0V output voltage and provides up to 8A of current. Power for the circuit can be provided from either a +36V to +75V or -36V to -75V DC source used in the telecom/datacom markets (48V modules), industrial environments, or in automotive 42V power systems. A high efficiency of up to 85% at 6A and 30W output power is achieved using a clamped two-transistor topology. Part of the efficiency improvement is due to the recovery of stored leakage and magnetizing inductance energy at the primary side. Galvanic isolation is achieved by an optocoupler and the surface-mount planar transformer. Operation at 250kHz allows the use of small magnetics and output capacitors. The EV kit provides cycle-bycycle current-limit protection. Additional steady-state fault protection is provided by integrating fault protection and internal thermal shutdown. The MAX5042 also has a programmable undervoltage lockout (UVLO). Warning: The MAX5042 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 EV kit with care to avoid possible personal injury. Do not short the -VIN pad to the “EV kit Ground” when the hot-swap MOSFET N1 is off (please consult the “Absolute Maximum Voltage Rating Diagram” in the MAX5042 data sheet). The -VIN pad and EV kit ground are at an 80V difference. The EV kit user should not probe the circuit with an oscilloscope probe and ground clip unless they have high-voltage hot-swap experience. Features ♦ Isolated, Hot-Pluggable 40W Forward DC-DC Converter ♦ ±36V to ±75V Input Range ♦ +5V Output Up to 8A (With Adequate Cooling) ♦ VOUT Regulation Better than 0.1% Over Line and Load ♦ 85% Efficiency at 48V and 6A ♦ Half-Brick Module Footprint and Pinout ♦ Cycle-by-Cycle Current-Limit Protection ♦ Programmable Integrating Fault Protection ♦ Internal Thermal Shutdown ♦ 250kHz Switching Frequency ♦ Designed for 500V Isolation ♦ Soft-Start ♦ Latched Shutdown ♦ Remote Output-Voltage Sense ♦ Fully Assembled and Tested Ordering Information PART TEMP RANGE IC PACKAGE MAX5042EVKIT 0°C to +50°C* 56 QFN *With 100LFM airflow. Component List DESIGNATION QTY C1 1 C2 1 C3, C10 2 C4 1 C5 1 C6, C12, C15 3 C7 1 DESCRIPTION 220µF ±20%, 100V electrolytic capacitor (18 x 16.5) Panasonic EEVFK2A221M 0.033µF ±10%, 250V ceramic capacitor (1206) TDK C3216X7R2E333K 1.0µF ±10%, 16V X5R ceramic capacitors (0805) Taiyo Yuden EMK212BJ105KG 0.1µF ±10%, 50V X7R ceramic capacitor (0805) Taiyo Yuden UMK212BJ104KG 0.0047µF ±10%, 250VAC X7R ceramic capacitor (2220) Murata GA355DR7GC472KY 0.1µF ±10%, 16V X7R ceramic capacitors (0603) Murata GRM39X7R104K016AD 1.0µF ±10%, 50V X7R ceramic capacitor (1210) Taiyo Yuden UMK325BJ105KH ________________________________________________________________ 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: MAX5042 General Description MAX5042 Evaluation Kit Evaluates: MAX5042 Component List (continued) DESIGNATION QTY C8 1 C9 1 C11 C13 1 C14 1 C16 1 C17, C18 C19 C20–C23 2 1 4 C24 0 C25 1 C26 1 D1, D2 2 D3 2 1 1 D4 1 L1 1 DESCRIPTION 0.33µF ±10%, 10V X5R ceramic capacitor (0603) Taiyo Yuden LMK107BJ334KA 220pF ±5%, 50V C0G ceramic capacitor (0603) Murata GRM39C0G221J050AD 0.1µF ±10%, 50V X7R ceramic capacitor (0805) Murata GRM40X7R104K050AD 1.0µF ±10%, 6.3V X5R ceramic capacitor (0603) Taiyo Yuden JMK107BJ105KA 100pF ±2%, 50V C0G ceramic capacitor (0603) Murata GRM1885C1H101GA01D 0.001µF, 200V X7R ceramic capacitor (0603) Murata GRM39-X7R102K200 150µF, 6.3V aluminum organic capacitors (X case) Kemet A700X157M006ATE015 0.15µF ±10%, 16V X7R ceramic capacitor (0603) Taiyo Yuden EMK107BJ154KA 0.68µF ±10%, 100V X7R ceramic capacitors (1812) TDK C4532X7R2A684K Not installed, ceramic capacitor (0603) 0.22µF ±10%, 10V X7R ceramic capacitor (0603) TDK C1608X7R1C224K 1000pF ±5%, 50V C0G ceramic capacitor (0603) TDK C1608C0G1H102J 100V, 1A Schottky diodes (SMA) Diodes Incorporated B1100 40V, 20A Schottky diode (TO-220AB) Vishay/General Semiconductor SBL2040CT 75V, 200mA ultra-fast diode (SOT-23) Fairchild MMBD4148 4.4µH, 15A inductor Pulse Engineering PA1494.442 DESIGNATION QTY N1 1 R1 1 DESCRIPTION 100V, 4.6A N-channel MOSFET (SO-8) Vishay Siliconix Si4482DY 25.5k,Ω ±1% resistor (0603) R2 1 8.25kΩ ±1% resistor (0603) R3 1 150Ω ±1% resistor (0805) R4, R5 2 10Ω ±5% resistors (0805) 200Ω ±1% resistor (0603) R6 1 R7, R8, R16, R17 0 Not installed, resistors (0603) R9 1 15Ω ±5% resistor (0805) R10 1 0.025Ω, 0.5W ±1% resistor (2010) IRC LRC-2010-R025F or Dale WSL-2010 0.025 1% R11 1 20Ω ±5% resistor (1206) R12 1 200kΩ ±1% resistor (0603) R13 1 1MΩ ±5% resistor (0603) R14 1 27Ω ±5% resistor (0805) R15 1 24.9kΩ ±1% resistor (0603) R18, R19 2 5.1Ω ±5% resistors (0603) R20 1 10kΩ ±5% resistor (1206) R21 1 1.24kΩ ±1% resistor (0603) R22 1 2kΩ ±5% resistor (0603) R23 1 10kΩ ±1% resistor (0603) R24 1 51Ω ±5% resistor (0603) R25 1 100kΩ ±5% resistor (0805) R26 1 0Ω ±5% resistor (0603) T1 1 200µH, 50W planar transformer Pulse Engineering PA0365 U1 1 U2 1 None 1 MAX5042ATN (56-pin QFN) 30V, 100% to 200% CTR optically isolated error amplifier (SO-8) Fairchild Semiconductor FOD2712 MAX5042 PC board None 2 Metal screws, 4-40 x 3/8 None 1 Nylon screw, 6-32 x 1/4 None 1 TO-220 thermally conductive insulating pad None 1 L-shaped aluminum heatsink _______________________________________________________________________________________ MAX5042 Evaluation Kit PHONE FAX Diodes Inc. SUPPLIER 805-446-4800 805-446-4850 WEBSITE Fairchild Semiconductor 888-522-5372 — IRC 361-992-7900 361-992-3377 Kemet 864-963-6300 864-963-6322 www.kemet.com Murata 770-436-1300 770-436-3030 www.murata.com www.diodes.com www.fairchildsemi.com www.irctt.com Panasonic 714-373-7366 714-737-7323 www.panasonic.com Pulse Engineering 858-674-8100 858-674-8262 www.pulseeng.com Taiyo Yuden 800-348-2496 847-925-0899 www.t-yuden.com TDK 847-803-6100 847-390-4405 www.component.tdk.com Vishay/Dale 402-564-3131 402-563-6296 www.vishay.com Vishay/General Semiconductor 760-804-9258 760-804-9259 www.vishay.com Vishay/Siliconix 610-644-1300 — www.vishay.com Note: Please indicate that you are using the MAX5042 when contacting these component suppliers. Quick Start Detailed Description Required Equipment The MAX5042 EV kit is an isolated, hot-pluggable, 40W forward DC-DC converter that provides +5V at up to 8A output with adequate cooling. The circuit can be powered from a +36V to +75V or a -36V to -75V DC source. Caution: Refer to the “Absolute Maximum Voltage Rating Diagram” in the MAX5042 data sheet when attempting to connect test equipment to the EV kit. The MAX5042 IC controls the hot-pluggable circuit, limiting the inrush current and rise time of the voltage to the 40W forward DC-DC converter circuit. The hot-pluggable circuit feature is provided by MOSFET N1, UVLO resistors R16/R17, the HSOK pad, and one MAX5042. When the MAX5042 EV kit is inserted into a live backplane system, the MAX5042 controls the turn-on rate of MOSFET N1 once the UVLO is above +30V (default UVLO). After MOSFET N1 is completely enhanced, the HSOK pad open-drain signal pulls low indicating that the hot swap was successful. Next, the 40W forward DC-DC converter circuit starts switching at 250kHz. Note that the IC paddle is connected to the -VIN power rail and when MOSFET N1 is fully enhanced, the primary-side ground is connected to the -VIN power rail. Jumper JU2 is provided to bypass hot-plugging MOSFET N1. When using JU2, note that it will carry the full primary current. • ±36V to ±75V power supply capable of providing 3A • Voltmeter • A fan to provide at least 100LFM airflow for extended operation at 8A. The MAX5042 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. Forward DC-DC Converter Output 1) Connect a jumper wire from the VOUT pad to the +SENSE pad. 2) Connect a jumper wire from the SGND pad to the -SENSE pad. 3) Connect a voltmeter to the VOUT and SGND pads. 4) Connect the 36V to 75V power supply to the +VIN pad. Connect the power supply’s ground to the -VIN pad. Do not exceed 80V input voltage. 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, see the Evaluating Other Output Voltages section. _______________________________________________________________________________________ 3 Evaluates: MAX5042 Component Suppliers Evaluates: MAX5042 MAX5042 Evaluation Kit The 40W forward converter achieves high efficiency by using a clamped two-transistor power topology with both power transistors integrated on the MAX5042 IC. Cycleby-cycle current limiting protects the converter against short circuits at the output. Current-sense resistor R10 senses the current through the primary of transformer T1 and then turns off both internal transistors when the 156mV trip level is reached. For a continuous short circuit at the output, the MAX5042’s fault integration feature provides hiccup fault protection, thus greatly minimizing destructive temperature rise. The planar surface-mount transformer features a bias winding, which, along with diode D4, resistor R9, and capacitor C7, powers the MAX5042 IC after PWM startup is complete. A reset winding is not required with a clamped two-transistor power topology. Schottky diodes D1 and D2 recover the magnetic energy stored in the core and feed it back to the +VIN input when both internal transistors turn off. The transformer provides galvanic isolation. On the transformer’s secondary side, optically isolated error amplifier U2 along with feedback resistors R1 and R2 provide voltage feedback to the primary side. The MAX5042 receives the voltage feedback signal on the primary side. Biasing resistor R21 provides biasing for the optocoupler transistor while the resistor/capacitor network R6/C8 provides compensation. Remote output-voltage sensing is provided by the +SENSE and -SENSE for accurate output-voltage regulation across the load. The soft-start feature allows the output voltage to slowly ramp up in a controlled manner within 4ms. The MAX5042 switches at a preconfigured 250kHz frequency set by resistor R15 and capacitor C14. The output provides up to 8A of continuous current when a cooling fan with at least 100LFM airflow is used. Dual-diode D3’s heatsink is connected to SGND. The 6-layer PC board layout and component placement has been designed for the industry-standard half-brick footprint and pinout. Resistor/capacitor network R14 and C2 prevent voltage overshoot as a result of the ±VIN input line inductance when hot plugging the EV kit. 4 Shutdown Shutdown Mode The MAX5042 EV kit features a jumper pad (JU1) and a hole-pad (SHDN) to remotely shut down the hot-pluggable, 40W forward DC-DC converter. Once the MAX5042 EV kit is shut down by either jumper method, the power to the EV kit must be cycled on/off before the MAX5042 starts switching again. Jumper pad JU1 can be used to manually shut down. An isolated optocoupler with an open-collector/drain transistor or relay contact can be connected across jumper JU1 to remotely shut down the EV kit. Evaluating Other Output Voltages, Current Limits, Soft-Starts and UVLOs VOUT Output Voltage The MAX5042 EV kit’s output (VOUT) is set to +5.0V by feedback resistors R1 and R2. To generate output voltages other than +5.0V (from +3.2V to +5.0V), select different voltage-divider resistors (R1, R2). Resistor R1 is typically chosen to be less than 25kΩ. Using the desired output voltage, resistor R2 is then found by the following equation: R1 R2 = VOUT − 1 V REF where VREF is 1.24V and VOUT is the desired output voltage. The maximum output current should be limited to less than 8A. The usable output voltage range for the EV kit is +3.2V to +5.0V. U2 and resistor R3 limit the minimum output voltage (VOUT) to +3.2V. _______________________________________________________________________________________ MAX5042 Evaluation Kit R10 = VSENSE NS N × 1.9 × IOUT(MAX) P where V SENSE = 0.156V, N S = 4, N P = 10 and IOUT(MAX) = maximum DC output current (8A as configured). There are errors introduced as a result of the presence of the transformer’s magnetic inductance and output inductor ripple current. Soft-Start The MAX5042 EV kit limits the output voltage rate of rise with a soft-start feature. Capacitor C11 (0.1µF), sets the ramp time to approximately 4ms. To evaluate other soft-start ramp times, replace capacitor C11 with another surface-mount capacitor (0805 size) as determined by the following equation: 32µA × soft start _ time C11 = 1.4 V Undervoltage Lockout (UVLO) The MAX5042 EV kit features a UVLO circuit that prevents operation below the programmed input supply start voltage. Resistors R7 and R8 set the EV kit’s input voltage brownout UVLO. To evaluate input UVLO voltages other than the default (31.5V), install resistors R7 and R8 (0603 size) with the desired resistor values. Using the startup voltage, resistor R7 is then found by the following equation: ( V IN(STARTUP) − 1.24V R7 = 1.24V ) × R8 where VIN(STARTUP) is the desired startup voltage at which the EV kit starts and resistor R8 is typically 10kΩ. Calculating the Hot-Swap MOSFET Snubber Resistor/Capacitor Values Resistor R14 and capacitor C2 are series connected across the drain/source terminals of hot-swap MOSFET N1 to prevent voltage overshoot as a result of the ±VIN input line inductance when hot-plugging the EV kit. To calculate new values for capacitor C2 and resistor R14 use the following equations: C2 = 75 × CDS _ 30V R7 = 1 × 3 L WIRING C DS _ 30V where: CDS_30V is the hot-swap MOSFET N1 drain-tosource approximate capacitance at a 30V bias point. LWIRING is the total approximate inductance of the wiring or backplane connected to the EV kit’s ±VIN inputs. where soft start_time is the desired soft-start time in seconds. _______________________________________________________________________________________ 5 Evaluates: MAX5042 Current Limiting The EV kit features cycle-by-cycle current limiting for the transformer primary current. The MAX5042 IC turns off both internal switching transistors when the voltage across the CSP and CSN pins of the MAX5042 reaches 156mV. Current-sense resistor R10 (R10 = 0.025Ω) limits the peak primary current to approximately 6.2A (156mV/0.025Ω = 6.2A). This limits short-circuit current on the secondary output (VOUT) to approximately 14A. To evaluate lower current limits, current-sense resistor R10 must be replaced with a different value surfacemount resistor (1206 size) as determined by the following equation: MAX5042 Evaluation Kit Evaluates: MAX5042 Forward DC-DC Converter Waveforms EFFICIENCY vs. OUTPUT CURRENT 100 +VIN = 48V 90 EFFICIENCY (%) 80 5V 70 60 50 1V/div 40 30 20 0V 10 0 0 1 2 3 4 5 6 7 8 9 1µs/div 10 OUTPUT CURRENT (A) 100LFM AIR FLOW Figure 2. Output Voltage Transient at Power-Up (+VIN = 48V, IOUT = 5A) Figure 1. Efficiency vs. Output Current (+VIN = 48V) 10V/div 10V/div 0V 0V 1µs/div 1µs/div Figure 3. Diode D1 Anode to Resistor R10 (MAX5042 QL* Transistor) Voltage Waveform, +VIN = 48V. Figure 4. Diode D2 Cathode to PWMPNEG Plane (MAX5042 QH* Transistor) Voltage Waveform, +VIN = 48V. *QL is the MAX5042 Internal Low-Side Transistor. *QH is the MAX5042 Internal High-Side Transistor. 6 _______________________________________________________________________________________ SHDN R25 100kΩ +VIN (HSOK WITH RESPECT TO -VIN) HSOK TP1 R20 10kΩ C12 0.1µF C9 220pF C14 100pF JU1 1 2 R14 27Ω -VIN RCOSC REG5 HSOK PWMSD SYNC 32 CSOUT 35 PWMNEG R15 24.9kΩ 1% 10 39 26 13 12 8 DRVIN 6 CSS 3 RCFF 4 RAMP 38 REG9 55 DRNH C22 0.68µF 100V BST 31 IC_PADDLE UVLO CSN SRC SRC SRC SRC SRC CSP REG15 IS CONNECTED TO U1 PWMNEG. NOTE: IC PADDLE CONNECTED TO -VIN R16 OPEN +VIN VF 57 46 34 16 17 20 21 24 33 41 18 XFRMRL 19 XFRMRL 22 XFRMRL 23 XFRMRL 27 1 2 14 15 40 42 43 44 9 45 37 56 5 MAX5042 U1 7 49 XFRMRH 50 XFRMRH 52 XFRMRH 53 XFRMRH 54 DRNH C21 0.68µF 100V 51 DRNH -VIN +VIN -VIN R17 1 4 2 OPEN 1 3 JU2 N1 2 7 8 5, 6 28 29 25 HSGATE 30 48 DRNH NEGIN POSINHS 47 POSINPWM C11 0.1µF 11 FLINT 36 DRVDEL C25 0.22µF C2 0.033µF R18 5.1Ω R23 10kΩ 1% +5V R22 2kΩ C13 1.0µF +5V R13 1MΩ C3 1.0µF C10 1.0µF R24 51Ω R19 5.1Ω HSDRAIN C23 0.68µF 100V HSEN N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. PWMPNEG N.C. PPWM N.C. OPTO R12 200kΩ 1% NEGIN C1 C20 220µF 0.68µF 100V 100V -VIN C24 OPEN C7 1.0µF D2 R7 OPEN R9 15Ω D1 R8 OPEN R26 0Ω +VIN C6 0.1µF D4 1 R10 0.025Ω 1% 3 6 1 5 2 VF T1 7 11 4T C26 1000pF +VIN 5T 10T +5V R6 200Ω 1% C8 0.33µF R21 1.24kΩ 1% C5 0.0047µF 250VAC C16 0.001µF 200V R11 20Ω 3 1 4 3 2 1 D3 N.C. E C N.C. 2 U2 L1 4.4µH GND COMP FB LED 5 6 7 8 C19 0.15µF VOUT R5 10Ω C17 150µF 6.3V C15 0.1µF R3 150Ω 1% R4 10Ω C18 150µF 6.3V -SENSE R2 8.25kΩ 1% R1 25.5kΩ 1% +SENSE SGND C4 0.1µF VOUT Evaluates: MAX5042 +VIN MAX5042 Evaluation Kit Figure 5. MAX5042 EV Kit Schematic _______________________________________________________________________________________ 7 Evaluates: MAX5042 MAX5042 Evaluation Kit Figure 6. MAX5042 EV Kit Component Placement Guide— Component Side Figure 7. MAX5042 EV Kit PC Board Layout—Component Side Figure 8. MAX5042 EV Kit PC Board Layout—Inner Layer, GND Layer 2 Figure 9. MAX5042 EV Kit PC Board Layout—Inner Layer, VCC Layer 3 8 _______________________________________________________________________________________ MAX5042 Evaluation Kit Figure 11. MAX5042 EV Kit PC Board Layout—Inner Layer, VCC Layer 5 Figure 12. MAX5042 EV Kit PC Board Layout—Solder Side Figure 13. MAX5042 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 © 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. Evaluates: MAX5042 Figure 10. MAX5042 EV Kit PC Board Layout—Inner Layer, GND Layer 4