19-2684; Rev 0; 12/02 MAX1951 Evaluation Kit Component List DESIGNATION C1, C5 C2 C3, C4 QTY DESCRIPTION 2 10µF ±20%, 6.3V X5R ceramic capacitors (1206) Taiyo Yuden JMK316BJ106ML or TDK C3216X5R0J106MT 1 220pF ±10%, 50V X7R ceramic capacitor (0603) Murata GRM39X7R221K050AD or Taiyo Yuden UMK107CH221KZ 2 0.1µF ±20%, 16V X7R ceramic capacitors (0603) Taiyo Yuden EMK107BJ104MA or TDK C1608X7R1C104K or Murata GRM 39X7R104K016AD C6 0 Not installed, capacitor (1206) D1 0 Not installed, Schottky diode JU1 1 2-pin header L1 1 2µH, 2A inductor Toko A915AY-2R0M or 1.8µH, 2A inductor Sumida CDRH4D28-1R8 Q1 1 NPN bipolar transistor SOT23 Fairchild MMBT3904 or Zetex FMMT413 R1 1 51.1kΩ ±1% resistor (0603) R2 1 15kΩ ±1% resistor (0603) R3 1 13kΩ ±1% resistor (0603) R4 1 10Ω ±5% resistor (0603) R5 1 10kΩ ±5% resistor (0603) MAX1951ESA 8-lead SO U1 1 None 1 Shunt None 1 MAX1951 PC board Features ♦ 2.6V to 5.5V Input Range ♦ Output Voltage Adjustable 0.8V to VIN (MAX1951) Fixed 1.8V (MAX1952) ♦ 1.5A Output Current ♦ Tiny Circuit Footprint: 0.55 ✕ 0.7in2 ♦ Low-Profile Components: < 3mm ♦ All Ceramic Design ♦ Fixed 1MHz Switching Frequency ♦ No External Schottky Diode Required ♦ Surface-Mount Construction ♦ Fully Assembled and Tested Ordering Information PART TEMP RANGE MAX1951EVKIT 0°C to +85°C IC PACKAGE 8 SO Note: To evaluate MAX1952ESA, request an MAX1952ESA-18 free sample with the MAX1951EVKIT. Quick Start The MAX1951 EV kit is a fully assembled and tested surface-mount board. Follow the steps below to verify board operation. Do not turn on the power supply until all connections are completed. 1) Verify that there is no shunt (open) across JU1 (shutdown disabled). 2) Connect a voltmeter and load (if any) to the VOUT pad. Connect the ground to the GND closest to VOUT. 3) Connect a 2.6V to 5.5V power supply to the VIN pad. Connect the power-supply ground to the GND pad closest to VIN. 4) Turn on the power supply and verify that the output voltage is 1.5V. To evaluate other output voltages with the MAX1951, see the Evaluating Other Output Voltages section. To evaluate the MAX1952, see the Evaluating the MAX1952 section. ________________________________________________________________ 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: MAX1951/MAX1952 General Description The MAX1951 evaluation kit (EV kit) provides a 1.5V output voltage from a 2.6V to 5.5V input source.The output voltage can be adjusted from 0.8V to VIN. The MAX1951 delivers up to 1.5A output current. The MAX1951 is a fixed-frequency, pulse-width modulated (PWM) step-down switching regulator with internal synchronous-rectifier. Operation at 1MHz minimizes external components. The MAX1951 EV kit can also be used to evaluate other output voltages by changing the feedback resistors R2 and R3. The EV kit can also be used to evaluate the MAX1952, which is a 1.5A PWM step-down switching regulator with a 1.8V fixed output voltage. Evaluates: MAX1951/MAX1952 MAX1951 Evaluation Kit Component Suppliers PHONE FAX Fairchild SUPPLIER 888-522-5372 408-822-2102 www.fairchildsemi.com WEBSITE Murata 770-436-1300 770-436-3030 www.murata.com Sumida 847-545-6700 847-545-6720 www.sumida.com Taiyo Yuden 800-348-2496 847-925-0899 www.t-yuden.com TDK 847-803-6100 847-390-4405 www.component.tdk.com Toko 847-297-0070 847-699-1194 www.tokoam.com Zetex 631-543-7100 631-864-7630 www.zetex.com Note: Please indicate that you are using the MAX1951/MAX1952 when contacting these suppliers. Detailed Description transistor to control COMP pin. JU1 provides options to select the circuit operating modes, normal or shutdown mode. Table 1 lists JU1 functions. The MAX1951 EV kit provides a 1.5V output voltage from a 2.6V to 5.5V input voltage. The EV kit operates at 1MHz fixed frequency and delivers up to 1.5A of output current. An additional pad (D1) is provided on the bottom side of the EV kit for optimizing efficiency evaluation. Evaluating the MAX1952 The MAX1951 EV kit can be used to evaluate the MAX1952. To evaluate the MAX1952, change the MAX1951ESA to a MAX1952ESA-18, remove R2 and R3, and short the two pads labeled R3. Evaluating Other Output Voltages The MAX1951 EV kit can provide an output voltage from 0.8V to VIN. The default output voltage is set to 1.5V. To evaluate other output voltages, select R2 between 20kΩ and 50kΩ. R3 is calculated by: R3 = R2 (VOUT /0.8 - 1) For stable operation, minimum duty cycle should not be less than 18%. Table 1. Jumper JU1 Functions SHUNT LOCATION COMP PIN On Connected to GND MAX1951 is disabled, VOUT = 0V Off (Open) Connected to RC network MAX1951 is enabled when IN ≥ 2.25V, VOUT = 1.5V MAX1951 is disabled when IN < 2.25V, VOUT = 0V Shutdown Selection The MAX1951 enters shutdown mode when the COMP pin is below 0.17V or the IN pin is less than 2.25V. The MAX1951 EV kit incorporates JU1 with a bipolar VIN 2.6V TO 5.5V GND 8 C1 10µF 6.3V IN LX 7 U1 R4 10Ω 1 C3 0.1µF 3 6 D1 R3 OPEN 13kΩ 1% MAX1951 VCC FB GND REF PGND L1 2µH COMP MAX1951 OUTPUT VOUT C6 OPEN C5 10µF 6.3V GND 4 2 R2 15kΩ C4 1% 0.1µF 5 JU1 R5 10kΩ 3 1 Q1 2 R1 51.1kΩ C2 220pF Figure 1. MAX1951 EV Kit Schematic 2 _______________________________________________________________________________________ MAX1951 Evaluation Kit Figure 3. MAX1951 EV Kit PC Board Layout—Component Side Figure 4. MAX1951 EV Kit PC Board Layout—Solder Side Figure 5. MAX1951 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 _____________________ 3 © 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. Evaluates: MAX1951/MAX1952 Figure 2. MAX1951 EV Kit Component Placement Guide— Component Side