19-2089; Rev 0; 7/01 MAX1708 Evaluation Kit Features ♦ 0.7V to VOUT Input Voltage Range ♦ Pin-Selectable +3.3V or +5V Output Voltage (+5V as Shipped) ♦ Adjustable Output Voltage (+2.5V to +5.5V, External Divider) ♦ Up to 2A Output Current ♦ 600kHz PWM Operation ♦ Internal 5A MOSFET Switch ♦ 1µA IC Shutdown Current ♦ Surface-Mount Components ♦ Fully Assembled and Tested Ordering Information PART TEMP RANGE MAX1708EVKIT 0°C to +70°C IC PACKAGE 16 QSOP Component List DESIGNATION QTY C1, C4 0 Not installed (D case) C2 1 150µF, 6.3V low-ESR capacitor (D case) Sanyo 6TPB150M or Panasonic EEFUE0J151R C3 1 150µF, 6.3V 15mΩ low-ESR capacitor (D case) Panasonic EEFUE0J151R C5, C6, C10 3 0.1µF ceramic capacitors (1206) C7 1 0.22µF ceramic capacitor (1206) C8 1 1µF, 16V ceramic capacitor (1206) Taiyo Yuden EMK316BJ105KL or TDK C3216X7R1C105M D1 1 DESCRIPTION 5A Schottky diode (SMC case) Central Semiconductor CMSH5-20 or CMSH5-40 DESIGNATION QTY DESCRIPTION L1 1 2.2µH power inductor Coilcraft DO3316P-222HC (unshielded) or Coiltronics UP2B2R2 (unshielded) or Sumida CDRH104R-2R5 (2.5µH, shielded) R1, R3 0 Not installed (1206) R2 0 Not installed, (short PC trace) (1206) R4 R5–R8 1 2Ω ±5% resistor (1206) 4 1MΩ ±5% resistors (1206) U1 1 MAX1708EEE (16-pinQSOP) JU1, JU2, JU3 3 2-pin headers None 3 Shunts None 1 MAX1708 PC board None 1 MAX1708 EV kit data sheet None 1 MAX1708 data sheet ________________________________________________________________ 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: MAX1708 General Description The MAX1708 evaluation kit (EV kit) is a step-up DC-DC switching regulator for 1- to 3-cell battery inputs as well as +2.5V or +3.3V regulated supply inputs. The EV kit accepts a positive input between 0.7V and VOUT, and converts it to a higher, pin-selectable output voltage. Efficiency is up to 90% with output load currents to 2A. This EV kit operates at fixed 600kHz PWM frequency, allowing the use of a small inductor. A movable jumper on the EV kit selects either a +3.3V or +5V output voltage. Additional pads on the board accommodate the resistors for output adjustment. This EV kit uses surface-mount components and is fully assembled and tested for quick evaluation. Evaluates: MAX1708 MAX1708 Evaluation Kit Component Suppliers SUPPLIER PHONE FAX Central Semiconductor 631-435-1110 631-435-1824 Coilcraft 847-639-6400 847-639-1469 Coiltronics 561-752-5000 561-742-0134 Panasonic 714-373-7334 714-373-7323 Sanyo 619-661-6835 619-661-1055 Sumida 847-545-6700 847-545-6720 Taiyo Yuden 408-573-4150 408-573-4159 TDK 847-803-6100 847-390-4405 Note: Please indicate that you are using the MAX1708 when contacting these component suppliers. Quick Start The MAX1708 EV kit is fully assembled and tested. Follow these steps to verify board operation. Do not turn on the power supply until all connections are completed. 1) Connect a +3V supply to the VIN pad. Connect ground to the GND pad. 2) Connect a voltmeter to the VOUT pad. 4) Turn on the power supply and verify that the output voltage is 5V. Refer to the MAX1708 data sheet for output load during start up. 5) For other output voltages, refer to Setting the Output Voltage in the MAX1708 data sheet for instructions on selecting the feedback resistors R1 and R2. Detailed Description The MAX1708 EV kit provides a pin-selectable +3.3V or +5V output from a +0.7V to VOUT input voltage. The output voltage can also be adjusted with external resistors for voltages between +2.5V to +5.5V. The MAX1708 includes an internal MOSFET switch with a typical peak current limit of 5A, and which can deliver loads up to 2A. Connecting an external resistor from SS/ILIM to GND (R3) can also reduce the current limit. Connecting a capacitor from SS/ILIM to GND (C6) sets the soft-start rate. The EV kit operates at 600kHz switching frequency and allows the use of a small inductor value. The switching frequency can also be synchronized to an external clock ranging from 350kHz to 1MHz. Jumper Selection Three jumpers on the PC board allow the user to select several configurations. Table 1 lists the jumpers and their functions. 3) Remove all the shunts from JU1, JU2, JU3. Table 1. Jumper Functions JUMPER JU1 JU2 SHUNT LOCATION Not Installed PIN CONNECTION MAX1708 is enabled if ONA = VOUT MAX1708 is disabled if ONA = GND Installed ONB connected to VOUT Not Installed ONA connected to GND MAX1708 is disabled if ONB = VOUT Installed ONA connected to VOUT MAX1708 is enabled if ONB = GND Not Installed 3.3 /5 connected to VOUT VOUT is set to 5V. FB pin must be connected to ground (R2 = short) Installed 3.3 /5 connected to GND VOUT is set to 3.3V. FB pin must be connected to ground (R2 = short) 3.3 /5 connected to GND and resistor R1 and R2 are installed VOUT = adjustable between +2.5V to +5.5V range. Refer to Setting the Output Voltage in the MAX1708 data sheet for instructions on selecting the feedback resistors R1 and R2. Also cut the PC trace, shorting R2 JU3 Installed 2 MAX1708 OPERATION ONB connected to GND _______________________________________________________________________________________ MAX1708 Evaluation Kit Evaluates: MAX1708 VIN VOUT GND C2 150µF 6.3V L1 2.2µH C1 OPEN JU1 1 ONB LX ONB LX R5 1MΩ VOUT LX JU2 PGND 2 ONA VOUT PGND ONA U1 16 CLK OUT C3 150µF 6.3V 12 7 6 VOUT 5V AT 2A GND R4 2Ω 10 C5 0.1µF R1 OPEN 11 VOUT SS/LIM R8 1MΩ 8 C8 1µF 16V 13 C6 0.1µF C7 0.22µF C4 OPEN C10 0.1µF MAX1708 FB REF 1.25V 5 PGND R7 1MΩ R3 OPEN D1 14 R6 1MΩ CLK 3 4 REF 3.3/5 GND GND R2 SHORT (PC TRACE) 15 9 JU3 Figure 1. MAX1708 EV Kit Schematic _______________________________________________________________________________________ 3 Evaluates: MAX1708 MAX1708 Evaluation Kit 1.0" 1.0" Figure 2. MAX1708 EV Kit Component Placement Guide— Component Side Figure 3. MAX1708 EV Kit PC Board Layout—Component Side 1.0" Figure 4. MAX1708 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 © 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.