19-2516; Rev 0; 7/02 MAX1953 Evaluation Kit Component List MAX1953 Application Circuit DESIGNATION QTY DESCRIPTION C8 1 0.1µF ±10%, 50V X7R ceramic capacitor Taiyo Yuden UMK107BJ104KA C9, C10 2 10µF, 4V X5R ceramic capacitors Taiyo Yuden AMK212BJ106MG C11 1 270pF, 10V X7R ceramic capacitor Kemet C0402C271M8RAC C12 1 Not installed C13, C14 2 10µF, 6.3V X5R ceramic capacitors Taiyo Yuden JMK316BJ106ML C15 1 4.7µF, 6.3V X5R ceramic capacitor Taiyo Yuden JMK212BJ475MG C16 1 120pF, 50V COG ceramic capacitor Murata GRM1885C1H121J D2 1 Schottky diode Central Semiconductor CMPSH1-4 JU3 1 Jumper, SIP3, 3-pin header Digi-Key S1012-3-ND or equivalent JU4 1 Jumper, SIP2, 2-pin header Digi-Key S1012-2-ND or equivalent L2 1 1µH, 3.6A, 20mΩ inductor Toko 817FY-1R0M Features ♦ Low-Cost Current-Mode Controllers ♦ Fixed-Frequency Pulse-Width Modulation (PWM) ♦ 0.8V (min) Output Voltage for MAX1953/MAX1954 ♦ 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 ♦ MAX1957 0.4V to 0.86VIN Output Voltage Range Sinking and Sourcing Capability of Up to 3A Output Voltage Tracks VREFIN ♦ Shutdown Feature ♦ All N-Channel MOSFETs 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 Assembled and Tested Ordering Information PART MAX1953EVKIT TEMP RANGE IC PACKAGE -40°C to +85°C 10 µMAX Recommended Equipment • 3V to 6V at +7A DC power supply or battery • Digital multimeter (DMM) • Ammeter (optional) ________________________________________________________________ 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/MAX1957 General Description The MAX1953 evaluation kit (EV kit) demonstrates three low-cost, 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. The MAX1957 application circuit demonstrates the ability to track VREFIN. The MAX1957 switches at 300kHz and is capable of sinking and sourcing up to 3A. This fully tested EV kit comes with the MAX1953 and MAX1954 evaluation circuits assembled. The MAX1953 EV kit also has complete layout to evaluate the MAX1957. Request free samples of the MAX1957 from Maxim to evaluate this circuit. Evaluates: MAX1953/MAX1954/MAX1957 MAX1953 Evaluation Kit Component List (continued) MAX1953 Application Circuit (continued) DESIGNATION QTY None 2 N2 DESCRIPTION MAX1954 Application Circuit (continued) DESIGNATION QTY Shunt Digikey S9000-ND or equivalent C5 1 1000pF, 10V ceramic capacitor Kemet C0402C102M8RAC 1 Dual, 20V, 9.4A, 0.014Ω MOSFET Fairchild FDS6898A C6 1 47pF, 10V ceramic capacitor Kemet C0402C470K8GAC R4 1 16.9kΩ ±1% resistor R5 1 8.06kΩ ±1% resistor C7 1 0.22µF, 10V X7R ceramic capacitor Kemet C0603C224M8RAC D1 1 Schottky diode Central Semiconductor CMPSH1-4 JU1, JU2 2 Jumpers, SIP2, 2-pin headers Digi-Key S1012-2-ND or equivalent L1 1 2.7µH, 6.6A, 12mΩ inductor Coilcraft DO3316P-272HC N1 1 Dual, 20V, 7.5A, 0.018Ω MOSFET Fairchild FDS6890A R1 1 9.09kΩ ±1% resistor R2 1 8.06kΩ ±1% resistor R3 1 62kΩ ±5% resistor None 2 Shunt Digikey S9000-ND or equivalent U1 1 MAX1954EUB R6 1 33kΩ ±5% resistor U2 1 MAX1953EUB MAX1954 Application Circuit DESIGNATION C1 C2 C3 QTY 1 1 0.1µF ±10%, 16V X7R ceramic capacitor Taiyo Yuden #EMK107BJ104KA 1 C4 DESCRIPTION 10µF, 16V X5R ceramic capacitor Taiyo Yuden EMK325BJ106MN 1 180µF, 4V, 15mΩ SP capacitor Panasonic EEFUE0G181R 10µF, 4V X5R ceramic capacitor Taiyo Yuden AMK212BJ106MG, (Not installed) DESCRIPTION Component Suppliers SUPPLIER COMPONENT PHONE Diodes 516-435-1110 www.centralsemi.com 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 Capacitors 408-573-4150 www.t-yuden.com Inductors 800-745-8656 www.toko.com Central Semiconductor Coiltronics Toko Quick Start The MAX1953/MAX1954 application circuits are fully assembled and tested. Follow these steps to verify board operation: MAX1954 1) Preset the DC power supply to 3V. Turn off the power supply. 2 WEBSITE 2) Verify that the shunt is in place at JU1 between positions 1 and 2. 3) Verify that there is no shunt at JU2. 4) Connect the positive lead of the power supply to the VIN pad and connect the negative lead of the power supply to GND0. 5) Turn on the power supply. _______________________________________________________________________________________ MAX1953 Evaluation Kit 7) Gradually increase the input voltage up to 5.5V, verifying that the output voltage remains at 1.7V. 8) Connect a 5A load between VOUT and GND0. 9) Verify that the voltage at VOUT is 1.7V. 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 320mV threshold, or remove the shunt from JU3 for a 210mV threshold. Evaluating the MAX1957 MAX1953 1) Preset the DC power supply to 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 the power supply 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 2.5V. 7) Gradually increase the input voltage up to 5.5V verifying that the output voltage remains at 2.5V. 8) Connect a 3A load between VOUT1 and GND2. 9) Verify that the voltage at VOUT1 is 2.5V. Detailed Description Evaluating Other Output Voltages The MAX1953/MAX1954 application circuits come assembled with output voltages of 2.5V and 1.7V, respectively. The MAX1953/MAX1954 are capable of adjustable output voltage settings from 0.8V to 0.86VIN. To adjust the output voltage, place a 1%, 8.06kΩ 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 Separate Power Supplies (MAX1954) Two power supplies can be used with the MAX1954 in order to extend the input voltage range to 13.2V. Remove the shunt on JU1 to use separate power supplies for VIN and VHSD. If the input voltage required is between 3V and 5.5V, VIN and VHSD can be connected together through JU1. The MAX1957 circuit comes unpopulated on the MAX1953 EV kit. Table 1 is a bill of materials for the MAX1957 circuit. To evaluate the MAX1957, request a free sample of the MAX1957 from Maxim and populate the MAX1953 EV kit board with the components specified. Setting the Output Voltage The MAX1957’s output voltage tracks the voltage at REFIN. Populate R7 and R8 with 2kΩ resistors to set the ratio to 1/2. Set a different input/output voltage ratio with the following equation: VOUT2 = VREFIN x (R8 /(R7 + R8)) Jumper Settings JU2, JU4, and JU5 Functions (Shutdown Mode) The MAX1953/MAX1954/MAX1957 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. To shutdown the MAX1957, place a shunt between pins 1 and 2 on JU5. 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. JU3 Function (ILIM Control, MAX1953) Use JU3 to select the current-limit threshold for the MAX1953. See Table 2 for the possible positions of JU3. 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. _______________________________________________________________________________________ 3 Evaluates: MAX1953/MAX1954/MAX1957 Setting the Current Limit (MAX1953) 6) Verify that the voltage at VOUT is 1.7V. Evaluates: MAX1953/MAX1954/MAX1957 MAX1953 Evaluation Kit Table 1. MAX1957 Bill of Materials DESIGNATION QTY 270µF, 2V, 15mΩ polymer capacitors Panasonic EEFUE0E271R L3 1 2.7µH, 6.6A,12mΩ inductor Coilcraft DO3316P-272HC 1 10µF, 6.3V X5R ceramic capacitor Taiyo Yuden JMK316BJ106ML N3 1 Dual, 20V, 7.5A, 0.018Ω MOSFET Fairchild FDS6890A C21 1 4.7µF, 6.3V X5R ceramic capacitor Taiyo Yuden JMK212BJ475MG None 1 Shunt Digi-Key S9000-ND or equivalent C22 1 470pF, 10V ceramic capacitor Kemet C0402C471M8RAC R7, R8 2 2kΩ ±1% resistors R9 1 51.1kΩ ±5% resistor R10 1 10kΩ 5% resistor C23, C24 2 0.1µF ±10%, 50V X7R ceramic capacitors Taiyo Yuden UMK107BJ104KA U3 1 MAX1957EUB C25, C26, C27 3 22µF, 6.3V X5R ceramic capacitors Taiyo Yuden JMK316BJ226ML C28 1 68pF, 10V ceramic capacitor Kemet C0402C680K8GAC C29 1 1500pF, 50V X7R ceramic capacitor Murata GRM188R71H152K D3 1 JU5 1 DESIGNATION QTY C17, C18, C19 3 C20 DESCRIPTION DESCRIPTION Table 2. JU3 Positions SHUNT LOCATION ILIM VCS (mV) Schottky diode Central Semiconductor CMPSH1-4 Between 1 and 2 Connected to GND 105 None Floating 210 Jumper, SIP2, 2-pin header Digikey S1012-2-ND or equivalent Between 2 and 3 Connected to IN 320 VHSD 5.5V TO 13.2V JU1 1 VIN 5V 2 C1 10µF D1 CMPSH1-4 HSD N1 FAIRCHILD FDS6890A BST IN C7 0.22µF DH U1 MAX1954 JU2 COMP/ SHDN 2 1 C5 1000pF R3 62kΩ C6 47pF LX DL C2 0.1µF N N L1 2.7µH, 6.6A COILCRAFT DO3316P-272HG R1 9.09kΩ C3 C4 180µF OPEN POLYMER PGND GND FB VOUT 1.7V AT 5A R2 8.06kΩ Figure 1. MAX1954 EV Kit Schematic 4 _______________________________________________________________________________________ MAX1953 Evaluation Kit Evaluates: MAX1953/MAX1954/MAX1957 VIN1 3V to 3.6V C15 4.7µF C14 10µF 3 JU3 IN 2 BST U2 DH MAX1953 R6 33kΩ C11 270pF LX N C8 0.1µF C12 OPEN L2 1µH, 3.6A TOKO 817FY-1ROM VOUT1 2.5V AT 3A R4 16.9kΩ N DL COMP/ SHDN 2 1 N2 FAIRCHILD FDS6898A ILIM 1 JU4 C13 10µF D2 CMPSH1-4 C9 10µF PGND R5 8.06kΩ FB GND C10 10µF C16 120pF Figure 2. MAX1953 EV Kit Schematic VIN2 3V to 3.6V C20 10µF C21 4.7µF REFIN 2.5V R7 2kΩ IN BST D3 CMPSH1-4 C25 22µF JU5 C22 470pF R9 51.1kΩ MAX1957 COMP/ SHDN 2 1 U3 C23 0.1µF C28 68pF DH LX C24 0.1µF N N DL L3 2.7µH, 6.6A COILCRAFT DO3316-272HC VOUT2 1.25V AT 3A C29 1500pF C17 C18 C19 270µF 270µF 270µF PGND R10 10kΩ GND C27 22µF N3 FAIRCHILD FDS6890A REFIN R8 2kΩ C26 22µF POLYMER FB Figure 3. MAX1957 EV Kit Schematic _______________________________________________________________________________________ 5 Evaluates: MAX1953/MAX1954/MAX1957 MAX1953 Evaluation Kit 1.0" Figure 4. MAX1953 EV Kit Component Placement Guide—Top Silkscreen 6 _______________________________________________________________________________________ MAX1953 Evaluation Kit Evaluates: MAX1953/MAX1954/MAX1957 1.0" Figure 5. MAX1953 EV Kit PC Board Layout—Component Side _______________________________________________________________________________________ 7 Evaluates: MAX1953/MAX1954/MAX1957 MAX1953 Evaluation Kit 1.0" 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. 8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.