19-0964; Rev 0; 8/07 MAX15005A Evaluation Kit Features The MAX15005A evaluation kit (EV kit) is a fully assembled and tested PCB that contains an 11W flyback DCDC converter for vacuum-fluorescent displays (VFDs) in automotive applications. The circuit uses a MAX15005A high-performance, current-mode pulse-width modulation (PWM) controller in a 16-pin TSSOP package. The EV kit circuit is configured for output voltages of 3V, 60V, and 110V, and provides up to 650mA, 12mA, and 55mA of current from the respective output. Additionally, a 5V lowdropout (LDO) voltage regulator output is provided that can source up to 15mA. Power for the EV kit circuit is provided from a 6.5V to 16V DC source. The MAX15005A EV kit input circuit can sustain a 40V transient. High efficiency of up to 71% is achieved using a singletransistor flyback DC-DC converter topology. Low cost is achieved through the use of direct secondary-side regulation that does not require optical couplers. Input undervoltage lockout (UVLO), output overvoltage protection (OVP), and soft-start provide for a robust 11W power supply. 6.5V to 16V DC Input Range Operation at 100kHz minimizes the size of the transformer and passive components. Warning: The MAX15005A 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. High-Accuracy Undervoltage Lockout (UVLO) 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. Outputs 3V Provides Up to 650mA (VFD Filament) 60V Provides Up to 12mA (VFD Grid) 110V Provides Up to 55mA (VFD Anode) Output Voltage Accuracy 110V (Anode) = 3% (Regulated Output) 60V (Grid) = 5% (Proportional Loading) 3V (Filament) = 10% (Proportional Loading) 71% Efficiency at 16V Input and Full Load 5V LDO Output Provides Up to 15mA Hiccup Current-Limit and Overtemperature Shutdown 100kHz Switching Frequency Capacitor Adjustable Soft-Start Output Overvoltage Protection (OVP) Capable of Synchronizing to an External Clock Low-Cost, Robust Flyback Design Fully Assembled and Tested Ordering Information PART TYPE MAX15005AEVKIT+ EV Kit +Denotes lead-free and RoHS-compliant. Component List DESIGNATION QTY 330F, 50V electrolytic capacitor (12.5mm x 13.5mm) Panasonic EEVFK1H331Q C4 1 100pF 2%, 50V C0G ceramic capacitor (0603) Murata GRM1885C1H101G 1 0.1F 10%, 50V X7R ceramic capacitor (0603) Murata GRM188R71H104K C5 1 1000pF 5%, 50V C0G ceramic capacitor (0603) Murata GRM1885C1H102J 2 1F 10%, 16V X7R ceramic capacitors (0805) Murata GRM21BR71C105K C6 1 4700pF 10%, 50V X7R ceramic capacitor (0603) Murata GMR188R71H472K DESIGNATION QTY C1 1 C2 C3, C10 DESCRIPTION DESCRIPTION ________________________________________________________________ Maxim Integrated Products 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. 1 Evaluates: MAX15005A General Description Evaluates: MAX15005A MAX15005A Evaluation Kit Component List (continued) DESIGNATION QTY C7 1 47pF 5%, 50V C0G ceramic capacitor (0603) Murata GRM1885C1H470J 1 0.68F 10%, 16V X7R ceramic capacitor (0805) Murata GRM219R71C684K C8 C9 C11 C12, C14 C13 C15 C16 C17 C18 1 560pF 5%, 50V C0G ceramic capacitor (0603) Murata GRM1885C1H561J 1 2200pF 10%, 100V X7R ceramic capacitor (0603) Murata GRM188R72A222K 2 1 1 1 1 1 100pF 10%, 63V C0G ceramic capacitors (1206) TKD C3216C0G2J101K 10F, 200V electrolytic capacitor (10mm x 10.5mm) SANYO 200CE10FS 22F, 80V electrolytic capacitor (8mm x 10.2mm) Panasonic EEEFK1K220P 330F, 6.3V electrolytic capacitor (8mm x 10.5mm) SANYO 6CE330EX 2.2F 20%, 10V X5R ceramic capacitor (0603) AVX 0603ZD225MAT 4700pF 10%, 100V X7R ceramic capacitor (0805) Murata GRM219R72A472K DESIGNATION QTY DESCRIPTION D4 1 40V, 3A Schottky diode (SMA) Diodes Inc. B340A-13-F D5 1 8.2V, 350mW 5% Zener diode (SOT23) Central Semiconductor CMPZ5237B JU1, JU2 2 2-pin headers JU3 1 3-pin header N1 1 80V, 1.4A n-channel MOSFET (8-pin SO) Vishay Si4896DY-T1-E3 R1 1 11.5k 1% resistor (0603) R2 1 560 5% resistor (1210) R3 1 51 5% resistor (0805) R4 1 402k 1% resistor (0603) R5 1 1k 5% resistor (0603) R6 1 0.070 1% power resistor (2010) IRC LRC-LR2010LF-01-R070-F R7 1 510 5% resistor (1206) R8 1 100k 5% resistor (1206) R9 1 220 5% resistor (1206) R10 1 36k 5% resistor (1206) R11 1 1.33M 1% resistor (0603) R12 1 12.1k 1% resistor (0603) R13 1 118k 1% resistor (0603) R14 1 1.33k 1% resistor (0603) R15 1 100 5% resistor (0805) R16 1 10 5% resistor (1210) R17 1 187k 1% resistor (0603) R18 1 47.5k 1% resistor (0603) R19 1 10k 5% resistor (0805) R20 1 232k 1% resistor (0603) D1 1 100V, 1A super-fast diode (SMA) Diodes Inc. ES1B-13-F T1 1 15H, 10W, 1:3.438:2.813:0.188 turn, 100kHz transformer (10-pin gull wing) Coiltronics CTX03-17677-R D2 1 600V, 1A super-fast diode (SMB) Diodes Inc. MURS160-F U1 1 MAX15005AAUE+ (16-pin TSSOP-EP) -- 2 Shunts (JU1, JU2, JU3) -- 1 PCB: MAX15005A Evaluation Kit+ D3 2 DESCRIPTION 1 400V, 1A super-fast diode (SMA) Diodes Inc. MURS140-13-F _______________________________________________________________________________________ MAX15005A Evaluation Kit SUPPLIER PHONE WEBSITE AVX Corp. 843-946-0238 Central Semiconductor 631-435-1110 www.avxcorp.com www.centralsemi.com Cooper Electronic Tech./Coiltronics 561-752-5000 www.cooperet.com Diodes Inc. 805-446-4800 www.diodes.com IRC 361-992-7900 www.irctt.com Murata Mfg. Co., Ltd. 770-436-1300 www.murata.com Panasonic Corp. 714-373-7366 www.panasonic.com SANYO Corp. 619-661-6322 www.sanyodevice.com Vishay 402-563-6866 www.vishay.com Note: Indicate that you are using the MAX15005A when contacting these component suppliers. Quick Start Required Equipment Before beginning, the following equipment is needed: * One 6.5V to 16V power supply capable of providing up to 3A * Three voltmeters Procedure (Outputs) The MAX15005A 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 a voltmeter to the FILAMENT+ and FILAMENT- pads. 2) Connect the second voltmeter to the V_GRID and PGND pads. 3) Connect the third voltmeter to the V_ANODE and PGND pads. 4) Verify that a shunt is installed across the pins of jumpers JU1 (ON/OFF) and JU2 (SYNC). 5) Verify that a shunt is installed across pins 2-3 of jumper JU3 (OVP). 6) Connect the power supply's positive terminal to the VIN pad. Connect the power supply's ground to the PGND pad. 7) Turn on the power supply above 7V and verify the following voltmeters readings: * FILAMENT = 3V * V_GRID = 60V * V_ANODE = 110V The maximum current for each output should be limited to less than 650mA, 12mA, and 55mA for each respective output detailed above in step 7. Detailed Description The MAX15005A EV kit is an 11W flyback DC-DC converter that provides output voltages of 3V at up to 650mA, 60V at up to 12mA, and 110V at up to 55mA. The MAX15005A flyback power supply is designed to provide power to automotive VFDs. The circuit can be powered from a 6.5V to 16V DC source, which provides 3A to the EV kit. The flyback DC-DC converter achieves up to 71% efficiency and the single-transistor topology provides for a lower-cost design. The MAX15005A EV kit provides cycle-by-cycle primary-side current-limit protection. Current-sense resistor R6 senses the current through the transformer's (T1) primary winding, switching transistor (N1), and turns off the transistor when the trip level of 0.3V is reached. The MAX15005A EV kit features a resistor/ capacitor/diode (RCD) snubber network (R2, C11, and D1) to minimize leakage energy ringing and clamp the voltage at the drain of MOSFET N1 during switching. Secondary-side regulation through feedback resistors R13 and R14 provide 3% regulation for the 110V output (V_Anode). Resistors R8, R10, and R15 preload the respective output and assist with overall regulation at minimum loading. UVLO provides controlled turn-on and shutdown during brownouts, power-up, or power-down. The UVLO setting can be changed by replacing resistor R18. The MAX15005A analog soft-start allows the output voltage to slowly ramp up in a controlled manner within 56ms and is set by capacitor C8. The OVP is provided by independently sensing the 110V output (V_Anode) through resistors R11 and R12. _______________________________________________________________________________________ 3 Evaluates: MAX15005A Component Suppliers Evaluates: MAX15005A MAX15005A Evaluation Kit The MAX15005A controller switches at a fixed 100kHz frequency and is set by resistor/capacitor network R1 and C5. The switching duty cycle is varied to control energy transfer to the outputs. The maximum duty cycle is 50% for the EV kit's discontinuous current-mode flyback design. Shutdown Mode (Jumper- or RemoteControl Method) The MAX15005A EV kit features a jumper (JU1) that can be used to shut down the flyback DC-DC converter. An alternate shutdown method (remote control) can be done with a user-supplied relay contact connected to pin 2 of jumper JU1 of the EV kit. Table 1 shows jumper options. Table 1. Jumper JU1 Shutdown Mode SHUNT POSITION ON/OFF PIN MAX15005A EV KIT OUTPUT Installed UVLO resistors R17 and R18 determine startup voltage MAX15005A enabled Not installed Pulled low to PGND through resistor R18 Shutdown mode Not installed Relay contacts connected between JU1 pin 2 Remote mode SYNC Mode The MAX15005A can be synchronized to an external TTL/CMOS square-wave clock source. The 2-pin jumper (JU2) selects the SYNC mode of operation or 100kHz internal frequency for the MAX15005A. Table 2 shows jumper options. The TTL/CMOS square-wave clock source (from 105kHz to 130kHz) must provide the following signal qualities: * Output voltage: Logic-low = 0 to 0.8V Logic-high = 2V to 5.5V Table 2. Jumper JU2 SYNC Mode Functions SHUNT POSITION SYNC PIN MAX15005A OPERATING MODE Installed Connected to SGND Internal clock mode (100kHz set by R1 and C5) Not installed Connected to an external TTL/CMOS square-wave clock source at the SYNC and SGND pads Synchronization mode (synchronized to an external clock frequency) Evaluating Other Current Limits, Input UVLO, and Output OVP Shutdown Current Limiting The EV kit features current limiting for the transformer's primary current. The MAX15005A IC turns off switching MOSFET N1 when the voltage at the MAX15005A CS pin reaches 0.3V. Current-sense resistor R6 (0.07) limits the transformer peak primary current to 4.2A (0.3V / 0.07 = 4.2A). To evaluate a lower current limit, current-sense resistor R6 must be replaced with a different surface-mount resistor (2010 size), as determined by the following equation: R6 = (0.300V/IPRIMARY) where IPRIMARY is the transformer's maximum peak primary current. Input UVLO (ON/OFF) The MAX15005A EV kit features a brownout and inputsupply startup UVLO circuit that prevents operation below the programmed input-supply-start voltage. Resistors R17 and R18 set the input UVLO threshold of the EV kit. To change the input UVLO voltage, replace resistor R17 (or R18) with another surface-mount resistor (0603 size). Using the desired startup voltage, resistor R17 is then found by the following equation: ( VINSTARTUP ) R17 = - 1 x R18 1.230V where VINSTARTUP is the desired startup voltage that the EV kit starts at, and resistor R18 is typically in the 50k range (47.5k default). Refer to the Startup Operation/UVLO/ON/OFF section of the MAX15005A data sheet for additional information on the ON/OFF pin of the MAX15005A IC. * Output frequency = 105kHz to 130kHz * Minimum positive-pulse width = 50ns * Connect the external square-wave clock to the SYNC and PGND pads. Refer to the MAX15005A data sheet for more information on the SYNC pin. 4 _______________________________________________________________________________________ MAX15005A Evaluation Kit (OVP) R11 = - 1 x R12 1.228V where OVP is the desired voltage that the circuit shutdown is at and resistor R12 is typically in the 10kW range (12.1k default). See Table 3 for configuring jumper JU3 for output OVP protection. Input OVP Shutdown (Load Dump Protection) The MAX15005A EV kit OVP circuit can be reconfigured to provide load dump protection for VIN when it rises above the programmed VIN supply voltage (24.7V default). Jumper JU3 configures the circuit for input OVP protection when the shunt is placed across pins 12. Resistors R12 and R20 set the OVI threshold of the OVP circuit for the MAX15005A IC. To evaluate other OVP voltages, replace resistor R20 with another surface-mount resistor (0603 size). Using the desired OVP voltage, resistor R20 is then found by the following equation: (OVP) R20 = - 1 x R12 1.228V where OVP is the desired voltage that the circuit shutdown is at and resistor R12 is typically in the 10k range (12.1k default). See Table 3 for configuring jumper JU3 for input OVP protection. Table 3. Jumper JU3 OVP Shutdown SHUNT POSITION OVI PIN OVP OPERATION 1-2 Sense VIN input Input overvoltage protection (load dump) 2-3*) Sense V_ANODE output Output overvoltage protection Not installed No sensing OVP disabled *Default position. _______________________________________________________________________________________ 5 Evaluates: MAX15005A Output OVP Shutdown The MAX15005A EV kit features an OVP circuit that prevents operation above the programmed V_ANODE output supply voltage (136V default). Jumper JU3 configures the circuit for output OVP protection when the shunt is placed across pins 2-3. Resistors R11 and R12 set the OVI threshold of the OVP circuit for the MAX15005A IC. To evaluate other OVP voltages, replace resistor R11 with another surface-mount resistor (0603 size). Using the desired OVP voltage, resistor R11 is then found by the following equation: 6 V_ANODE SYNC SGND REG5 REG5 3 2 1 R20 232k 1% VIN R11 1.33M 1% PGND VIN JU1 JU3 2 1 R19 10k R1 11.5k 1% R18 47.5k 1% R17 187k 1% C1 330F 50V JU2 C5 1000pF C4 100pF 2 1 R12 12.1k 1% C2 0.1F 50V 8 7 6 5 4 3 2 1 SYNC SGND RTCT N.C. SLOPE OVI U1 17 EP MAX15005A ON/OFF IN SS FB COMP CS REG5 PGND OUT VCC 9 10 11 12 13 14 15 16 C8 0.68F C6 4700pF R4 402k 1% C9 560pF C10 1F 16V C3 1F 16V C7 47pF R5 1k REG5 R3 51 C18 4700pF 100V R16 10 R14 1.33k 1% R13 118k 1% 4 1 2 5 6 D1 R2 560 V_ANODE C11 2200pF 100V 3 R6 0.070 1% N1 7 8 1 4 T1 10 9 8 7 6 D2 R7 510 D4 R9 220 C12 100pF D3 C17 2.2F 10V C14 100pF R8 100k V_ANODE R15 100 R10 36k C13 10F 200V D5 C16 330F 6.3V C15 22F 80V FILAMENT- FILAMENT+ PGND V_GRID PGND V_ANODE Evaluates: MAX15005A MAX15005A Evaluation Kit Figure 1. MAX15005A EV Kit Schematic _______________________________________________________________________________________ MAX15005A Evaluation Kit Figure 3. MAX15005A EV Kit PCB Layout--Component Side Figure 4. MAX15005A EV Kit PCB Layout--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 (c) 2007 Maxim Integrated Products janet freed is a registered trademark of Maxim Integrated Products, Inc. Evaluates: MAX15005A Figure 2. MAX15005A EV Kit Component Placement Guide-- Component Side