19-3351; Rev 0; 7/04 MAX1954A Evaluation Kit The MAX1954A evaluation kit (EV kit) demonstrates the MAX1954A buck controller application circuit. The EV kit generates a 1.5V output voltage at load currents up to 5A from a 10.8V to 13.2V input voltage range independent of the IC supply voltage. The MAX1954A switches at 300kHz and has better than 90% efficiency with the supplied components. The EV kit comes fully assembled and tested. Features ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ Current-Mode Controller 300kHz Fixed-Frequency PWM 0.8V Minimum Output Voltage 10.8V to 13.2V Input Voltage Range >90% Efficiency Output Shutdown Mode All n-Channel MOSFET Design for Low Cost No Current-Sense Resistor Needed Foldback Short-Circuit Protection Thermal-Overload Protection Small 10-Pin µMAX® Package Assembled and Tested Ordering Information µMAX is a registered trademark of Maxim Integrated Products, Inc. PART TEMP RANGE MAX1954AEVKIT 0°C to +70°C IC PACKAGE 10 µMAX Component List DESIGNATION QTY C10 0 Not installed (0603) D1 1 Schottky diode (SOT23-F) Central Semiconductor CMPSH1-4 JU1, JU2 2 2-pin headers Sullins PTC36SAAN (36-pin strip, cut to size as needed) 1µF, 10V X7R ceramic capacitor (0603) TDK C1608X7R1A105K L1 1 2.7µH, 6.6A, 12mΩ inductor Coilcraft DO3316P-272HC 1 180µF, 2V, 9mΩ SP capacitor Panasonic EEFSX0D181R N1 1 Dual n-MOSFET 20V, 7.5A, 0.018Ω (8-pin SO) Fairchild FDS6890A 0 Not installed (0603) R1 1 7.15kΩ ±1% resistor (0603) 1 18pF ±5%, 50V C0H ceramic capacitor (0402) Taiyo Yuden UMK105CH180JW R2 1 8.06kΩ ±1% resistor (0603) R3 1 82kΩ ±5% resistor (0603) R4 1 2Ω ±5% resistor (0603) R5 0 Not installed (0603) U1 1 MAX1954AEUB None 2 Shunts DESIGNATION QTY C1 1 22µF, 16V X5R ceramic capacitor (1210) TDK C3225X5R1C226K C2 1 0.22µF, 10V X7R ceramic capacitor (0603) Kemet C0603C224M8RAC C3 1 C4 C5 C6 DESCRIPTION 1 470pF ±10%, 50V X7R ceramic capacitor (0402) Taiyo Yuden UMK105BJ471KW C8 1 0.1µF ±10%, 16V X5R ceramic capacitor (0603) Taiyo Yuden EMK107BJ104KA C9 1 1500pF, 50V X7R ceramic capacitor (0603) TDK C1608X7R1H152K C7 DESCRIPTION ________________________________________________________________ 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: MAX1954A General Description Evaluates: MAX1954A MAX1954A Evaluation Kit Component Suppliers SUPPLIER COMPONENT PHONE NUMBER Central Semiconductor WEBSITE Diodes 516-435-1110 Coilcraft Inductors 800-322-2645 www.centralsemi.com www.coilcraft.com Fairchild Semiconductor MOSFETs 408-721-2181 www.fairchildsemi.com Kemet Capacitors 864-963-6300 www.kemet.com Taiyo Yuden Capacitors 408-573-4150 www.t-yuden.com TDK Capacitors 81-3-5201-7200 www.component.tdk.com Note: Indicate you are using the MAX1954A when contacting these manufacturers. Recommended Equipment • 15V at 1A DC variable power supply • 5V at 100mA power supply • Digital multimeter (DMM) • 5A load • Ammeter (optional) Evaluating Other Output Voltages The MAX1954A EV kit comes preset to a 1.5V output voltage. The output of the MAX1954A is adjustable down to 0.8V. To adjust the output voltage, place a 1% resistor at R1 with a value corresponding to the equation: Quick Start The MAX1954A application circuit is fully assembled and tested. Follow these steps to verify board operation: 1) Preset the DC power supplies to 12V and 5V. Turn off the power supplies. Do not turn on the power supplies until all connections are complete. 2) Remove the shunt from JU1 and JU2. 3) Connect the positive lead of the 5V power supply to the VIN pad on the EV kit and connect the negative lead of the power supply to the GND pad on the EV kit. 4) Connect the positive lead of the 12V power supply to the VHSD pad on the EV kit and connect the negative lead of the power supply to the GND pad on the EV kit. 5) Connect the positive lead of the DMM to the VOUT pad on the EV kit and connect the negative lead of the DMM to the GND pad on the EV kit. 6) Turn on the power supplies. 7) Verify that the voltage at VOUT is 1.5V ±2.5%. 8) Connect a 5A load between VOUT and GND. 9) Verify that the voltage at VOUT is 1.5V ±2.5%. 2 Detailed Description R1 = 8.06 x 103 x ((VOUT / 0.8) - 1) Note that VOUT cannot exceed VIN and is limited by the maximum duty cycle of the MAX1954A. Refer to the MAX1954A data sheet for information on selecting output inductor, capacitor, and compensation components to optimize the circuit for different output voltages. Using a Single Power Supply If the input source is between 3V to 5.5V, install a shunt on JU1 (to connect VHSD and VIN), and connect the power supply between the VHSD pad and the GND pad on the EV kit. Refer to the MAX1954A data sheet for information on selecting the inductor, capacitors, and compensation components for optimum performance. Jumper Settings Jumper JU1 Function (HSD Control) Connect HSD to IN when using input voltages lower than 5.5V. Place a shunt on JU1 to connect HSD to IN. Jumper JU2 Function (Output Shutdown Mode) The MAX1954A features an output shutdown mode to minimize the quiescent current. To shut down the output, place a shunt between pins 1 and 2 on JU2. For normal operation remove the shunt from JU2. _______________________________________________________________________________________ MAX1954A Evaluation Kit Evaluates: MAX1954A VHSD +10.8V TO +13.2V VIN +3.0V TO +5.5V JU1 C1 22µF GND D1 CMPSH1-4 HSD BST IN C2 0.22µF C3 1µF U1 MAX1954A N1 FDS6890A DH R5 OPEN N C10 OPEN C8 0.1µF VOUT +1.5V AT 5A L1 2.7µH LX COMP/SHDN JU2 C7 R3 470pF 82kΩ C6 18pF DL PGND N R4 2Ω R1 7.15kΩ C4 180µF C5 OPEN C9 1500pF R2 8.06kΩ GND FB Figure 1. MAX1954A EV Kit Schematic Figure 2. MAX1954A EV Kit Component Placement Guide— Top Silkscreen Figure 3. MAX1954A EV Kit PC Board Layout—Component Side _______________________________________________________________________________________ 3 Evaluates: MAX1954A MAX1954A Evaluation Kit Figure 4. MAX1954A EV Kit PC Board Layout—Layer 2 Figure 5. MAX1954A EV Kit PC Board Layout—Layer 3 Figure 6. MAX1954A EV Kit PC Board 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. 4 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.