MAX1953EVKIT

19-2516; Rev 0; 10/05 MAX1953 Evaluation Kit The MAX1953 evaluation kit (EV kit) demonstrates two lowcost, buck-controller application circuits. The MAX1953 application circuit features an adjustable current limit. The 1MHz switching frequency renders a small footprint. The MAX1954 application circuit operates from a 3V to 13.2V input voltage range and is adjustable independent of the supply voltage. The MAX1954 switches at 300kHz and boasts 93% efficiency with the supplied components. This EV kit comes with the MAX1953 and MAX1954 evaluation circuits fully assembled and tested. Component List DESIGNATION QTY C1, C12 2 DESCRIPTION 1µF, 10V X7R ceramic capacitors (0603) TDK C1608X7R1A105K 1 0.22µF, 10V X7R ceramic capacitor (0603) Kemet C0603C224M8RAC C3 1 22µF, 16V X5R ceramic capacitor (1210) TDK C3225X5R1C226K C4 1 Not installed C5 1 180µF, 2V, 9mΩ SP capacitor Panasonic EEFSX0D181R C6 1 18pF ±5%, 50V C0H ceramic capacitor (0402) Taiyo Yuden UMK105CH180JW C7 1 470pF ±10%, 50V X7R ceramic capacitor (0402) Taiyo Yuden UMK105BJ471KW C2 Features ♦ Low-Cost Current-Mode Controllers ♦ Fixed-Frequency Pulse-Width Modulation (PWM) ♦ 0.8V (min) Output Voltage ♦ Operates from Low 3V Input Voltage ♦ MAX1953 1MHz Switching Frequency Small Component Size, Low Cost Adjustable Current Limit ♦ MAX1954 3V to 13.2V Input Voltage 93% Efficiency 300kHz Switching Frequency ♦ Shutdown Feature ♦ All n-Channel MOSFET Design for Low Cost ♦ No Current-Sense Resistor Needed ♦ Internal Digital Soft-Start ♦ Surface-Mount Components ♦ Thermal-Overload Protection ♦ Small 10-Pin µMAX® Package ♦ MAX1953/MAX1954 Circuit Fully Assembled and Tested Ordering Information PART TEMP RANGE MAX1953EVKIT 0°C to +70°C IC PACKAGE 10 µMAX Recommended Equipment Digital multimeter (DMM) 2 0.1µF ±10%, 16V X5R ceramic capacitors (0603) Taiyo Yuden EMK107BJ104KA • C8, C18 • Ammeter (optional) • Power supply 1: 3VDC to 14VDC at 3A C9, C19 2 Not installed (0603) • Power supply 2: 3VDC to 6VDC at 100mA 1 1500pF ±10%, 50V X7R ceramic capacitor (0603) TDK C1608X7R1H152K C10 Component List continued on next page. µMAX is a registered trademark of Maxim Integrated Products, Inc. ________________________________________________________________ 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: MAX1953/MAX1954 General Description Evaluates: MAX1953/MAX1954 MAX1953 Evaluation Kit Component List (continued) DESIGNATION QTY DESCRIPTION C11 1 22µF ±20%, 6.3V X5R ceramic capacitor (1206) Taiyo Yuden JMK316 BJ226ML C14 1 Not installed (0402) C15 1 C16, C17 2 C20 1 D1, D2 JU1, JU2, JU4 JU3 QTY DESCRIPTION L1 1 2.7µH, 6.6A, 12mΩ inductor Coilcraft DO3316P-272HC L2 1 1µH, 3.6A, 20mΩ inductor TOKO 817FY-1R0M 270pF ±5%, 50V C0G ceramic capacitor (0402) Taiyo Yuden UMK105 CG271JW N1, N2 2 Dual n-channel MOSFETs, 20V, 7.5A, 0.018Ω (SO-8) Fairchild FDS6890A 10µF ±10%, 6.3V X5R ceramic capacitors (0805) Taiyo Yuden JMK212 BJ106KG R1 1 7.15kΩ ±1% resistor (0603) R2, R7 2 8.06kΩ ±1% resistors (0603) R3 1 82kΩ ±5% resistor (0603) 4700pF ±10%, 50V X7R ceramic capacitor (0603) TDK C1608X7R1H472K R4, R9 2 Not installed (0603) R5, R10 2 2Ω ±5% resistors (0603) R6 1 10.2kΩ ±1% resistor (0603) 2 Schottky diodes (SOT23-F) Central Semiconductor CMPSH1-4 3 2-pin headers Sullins PTC36SAAN (36-pin strip, cut to size as needed) 1 DESIGNATION R8 1 27kΩ ±5% resistor (0603) U1 1 Maxim MAX1954EUB U2 1 Maxim MAX1953EUB — 4 Shunts Sullins STC02SYAN Digi-key S9000-ND 3-pin header Sullins PTC36SAAN (36-pin strip, cut to size as needed) Component Suppliers SUPPLIER Central Semiconductor COMPONENT PHONE WEBSITE Diodes 516-435-1110 www.centralsemi.com Coiltronics Inductors 561-752-5000 www.coiltronics.com Fairchild Semiconductor MOSFETs 408-721-2181 www.fairchildsemi.com Kemet Capacitors 864-963-6300 www.kemet.com Murata Capacitors 770-436-1300 www.murata.com Taiyo Yuden TOKO Capacitors 408-573-4150 www.t-yuden.com Inductors 800-745-8656 www.toko.com TDK Capacitors 847-803-6100 www.component.tdk.com Note: Indicate you are using the MAX1953/MAX1954 when contacting these component suppliers. Quick Start The MAX1953/MAX1954 application circuits are fully assembled and tested. Follow the steps below to verify board operation. MAX1954 1) Preset DC power supply 1 to 12V, and power supply 2 to 5V. Turn off the power supplies. 2) Verify that there is no shunt at JU1 and JU2. 2 3) Connect the positive lead of power supply 2 to the VIN pad and connect the negative lead of the power supply to GND. 4) Connect the positive lead of power supply 1 to the HSD pad, and connect the negative lead on the power supply to the GND pad. 5) Turn on power supply 1. 6) Turn on power supply 2. _______________________________________________________________________________________ MAX1953 Evaluation Kit 8) Connect a 5A load between VOUT and GND. JU2 and JU4 Functions (Shutdown Mode) 9) Verify that the voltage at VOUT is ~1.5V. MAX1953 1) Preset DC power supply 1 to 3.3V. Turn off the power supply. 2) Ensure that there is a shunt between positions 1 and 2 at JU3. 3) Verify that there is no shunt at JU4. 4) Connect the positive lead of power supply 1 to the VIN1 pad and connect the negative lead to the GND1 pad. 5) Turn on the power supply. 6) Verify that the voltage at VOUT1 is ~1.8V. 7) Connect a 3A load between VOUT1 and GND1. 8) Verify that the voltage at VOUT1 is ~1.8V. Detailed Description Evaluating Other Output Voltages The MAX1953/MAX1954 application circuits come assembled with output voltages of 1.8V and 1.5V, respectively. The MAX1953/MAX1954 are capable of adjustable output voltage settings from 0.8V to 0.86 x VIN. To adjust the output voltage, place an 8.06kΩ ±1% resistor at R2 (R5) and a 1% resistor at R1 (R4) with a value corresponding to the equation: R1 (R4) = 8.06 x 103 x ((VOUT / 0.8) - 1) VOUT can not exceed VIN. The compensation network may need to be optimized for each output voltage. Refer to the Stability and Compensation section of the MAX1953/MAX1954/ MAX1957 data sheet for the method to calculate the compensation components. Using a Single Power Supply (MAX1954) To use a single power supply with the MAX1954, the power-supply voltage must be between 3V and 5.5V. Connect the positive lead of the power supply to the HSD pad on the EV kit, and connect the negative lead of the power supply to the GND pad on the EV kit. Install a shunt on JU1. The MAX1953/MAX1954 feature a shutdown mode to minimize the quiescent current. To shut down the MAX1953, place a shunt between pins 1 and 2 on JU4. To shut down the MAX1954, place a shunt between pins 1 and 2 on JU2. JU1 Function (HSD Control, MAX1954) The HSD and IN pins on the MAX1954 can be connected when using input voltages lower than 5.5V. Place a shunt on JU1 to connect the HSD and IN pins. Setting the Current Limit (MAX1953) Use JU3 to set the short-circuit current-limit threshold for the MAX1953. Short JU3 between pins 1 and 2 for a 105mV threshold, between 2 and 3 for a 320mV threshold, or remove the shunt from JU3 for a 210mV threshold. Input Capacitance Guidelines An oscillation may occur in the input voltage when using the MAX1953 EV kit that shows up on the output. This is typically due to long input leads. An LC “tank” circuit is formed with the inductance of the input leads and the input capacitance. Use very short leads or add a high equivalent series resistance (ESR) capacitor (aluminum electrolytic or tantalum) at the input to stop this oscillation. This “detunes” the LC tank circuit and effectively stops the oscillation. Table 1. JU3 Positions SHUNT LOCATION ILIM VCS (mV) Between 1 and 2 Connected to GND 105 None Unconnected 210 Between 2 and 3 Connected to IN 320 _______________________________________________________________________________________ 3 Evaluates: MAX1953/MAX1954 Jumper Settings 7) Verify that the voltage at VOUT is ~1.5V. Evaluates: MAX1953/MAX1954 MAX1953 Evaluation Kit VHSD +10.8V TO +13.2V JU1 VIN +3.0V TO +5.5V GND 1 HSD 5 DH LX U1 MAX1954 C7 470pF 2 COMP/ SHDN R3 82kΩ BST IN C1 1µF C2 0.22µF JU2 C3 22µF D1 CMPSH1-4 C6 18pF DL PGND 4 FB GND N1 FDS6890A 10 8 9 C8 0.1µF 6 N N R4 OPEN C9 OPEN R5 2Ω VOUT +1.5V AT 5A L1 2.7µH C5 180µF R1 7.15kΩ C4 OPEN C10 1500pF 7 R2 8.06kΩ 3 VIN1 +3.0V TO +5.5V C12 1µF GND1 5 3 JU3 IN 1 2 1 U2 MAX1953 2 JU4 C15 270pF R8 27kΩ BST ILIM COMP/ SHDN C14 OPEN DH LX DL PGND 4 GND FB C11 22µF D2 CMPSH1-4 10 N2 FDS6890A R9 OPEN 8 C18 0.1µF N C19 L2 OPEN 1µH N R10 2Ω VOUT1 +1.8V AT 3A 9 6 7 3 C16 10µF R6 10.2kΩ C20 4700pF R7 8.06kΩ Figure 1. MAX1953 EV Kit Schematic 4 _______________________________________________________________________________________ C17 10µF MAX1953 Evaluation Kit Evaluates: MAX1953/MAX1954 Figure 2. MAX1953 EV Kit Component Placement Guide— Component Side Silkscreen Figure 3. MAX1953 EV Kit PC Board Layout—Component Side _______________________________________________________________________________________ 5 Evaluates: MAX1953/MAX1954 MAX1953 Evaluation Kit Figure 4. MAX1953 EV Kit PC Board Layout—Inner Layer 1 6 Figure 5. MAX1953 EV Kit PC Board Layout—Inner Layer 2 _______________________________________________________________________________________ MAX1953 Evaluation Kit Evaluates: MAX1953/MAX1954 Figure 6. MAX1953 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. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _________________ © 2005 Maxim Integrated Products Printed USA 7 is a registered trademark of Maxim Integrated Products, Inc.