19-1886; Rev 0; 12/00 MAX1761 Evaluation Kit The MAX1761 EV kit provides dual 1.8V and 2.5V output voltages from a +5V to +20V battery input range. It delivers up to a 2A output current for each output with greater than 90% efficiency. The EV kit operates at 300kHz switching frequency and has superior line- and load-transient response. This EV kit is a fully assembled and tested circuit board. It also allows the evaluation of other output voltages in the 1.0V to 5.5V range by changing feedback resistors R1–R4. Features ♦ +5V to +20V Input Voltage Range ♦ Preset 1.8V and 2.5V Output Voltages ♦ Adjustable Output Voltages (1V to 5.5V, external divider) ♦ 2A Output Current ♦ 300kHz Switching Frequency ♦ No Current-Sense Resistor ♦ 4µA V+ Shutdown Supply Current ♦ 5µA VL Shutdown Supply Current ♦ 16-Pin QSOP Package ♦ Low-Profile Components ♦ Fully Assembled and Tested Ordering Information PART TEMP. RANGE o o 0 C to +70 C MAX1761EVKIT IC PACKAGE 16 QSOP Component List DESIGNATION QTY C1 1 10µF, 25V ceramic capacitor (1812) Taiyo Yuden TMK432BJ106KM or TDK C4532X5R1E106M C2, C7–C11 0 Not installed (0805) C3, C4 C5 2 1 DESCRIPTION 220µF, 10V low-ESR 40mΩ capacitors Sanyo 10TPB220M or 330µF, 10V low-ESR 30mΩ capacitors Kemet T510X337M010AS 0.1µF ceramic capacitor (0805) DESIGNATION QTY DESCRIPTION L1, L2 2 7µH power inductors Sumida CDRH104R-7R0NC N1, P1, N2, P2 2 Dual N- and P-channel MOSFETs International Rectifier IRF7319 or Fairchild FDS8958A R1–R6 0 Not installed (0805) R7, R8 2 1MΩ ±5% resistors (0805) R9 1 10Ω ±5% resistor (0805) R10–R13 0 Not installed U1 1 MAX1761EEE (16-pin QSOP) SW1 1 DIP-3 dip switch 1 4.7µF, 10V X5R ceramic capacitor (1206) Taiyo Yuden LMK316BJ475ML C12 1 1µF, 25V X5R ceramic capacitor Taiyo Yuden TMK316BJ105ML None 4 Rubber bumpers 3M SJ-5007 Mouser 517-SJ-5007BK or equivalent D1, D2 0 Not installed Nihon EP10QY03 None 1 MAX1761 PC board None 1 MAX1761 data sheet None 1 MAX1761 EV kit data sheet C6 ________________________________________________________________ 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: MAX1761 General Description The MAX1761 evaluation kit (EV kit) demonstrates a standard 2A application circuit. This DC-DC converter steps down high-voltage batteries and/or AC adapters, generating a precision, low-voltage rail for use as chipset, I/O, and other low-voltage supplies in notebook computers and PDAs. Evaluates: MAX1761 MAX1761 Evaluation Kit Component Suppliers SUPPLIER PHONE FAX Fairchild 408-721-2181 408-721-1635 International Rectifier 310-322-3331 310-322-3332 Sanyo 619-661-6835 619-661-1055 Sumida 708-956-0666 708-956-0702 Taiyo Yuden 408-573-4150 408-573-4159 TDK 847-390-4373 847-390-4428 Note: Please indicate that you are using the MAX1761 when contacting these suppliers. 4) Turn on the power and verify that the output voltages are 1.8V and 2.5V. 5) Refer to the Output Voltage Selection section in the MAX1761 data sheet to modify the board for different output voltages. 6) Refer to the Setting the Current Limit section in the MAX1761 data sheet to modify the board for a higher output current. Detailed Description Switch Settings Table 1 lists switch settings. Evaluating Other Output Voltages Quick Start The MAX1761 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. The EV kit outputs are preset to +1.8V and +2.5V. However, the output voltages can also be adjusted between 1.0V and 5.5V by selecting R1/R2 and R3/R4 values. R1 and R3 are given by: R1 or R3 = (R2 or R4) ((VOUT / VFB) -1) where VFB = 1.0V. 1) Connect voltmeters and loads (if any) to the VOUT pads. 2) Verify that switches ON1 and ON2 (SW1) are in the on position. 3) Connect a +5V to +20V supply to the pads marked VBATT and GND. Table 1. Switch SW1 Functions SW1 LOCATION 2 ON1 PIN ON2 PIN OPERATION MODE ON1 = low, ON2 = X Connected to GND, VOUT1 = 0, VOUT2 = 0 ON1 = high, ON2 = low Connected to VBATT, VOUT1 = 2.5V, VOUT2 = depends on ON2 Connected to GND, VOUT2 = 0 VOUT1 is in normal mode. VOUT2 is in shutdown mode. ON1 = high, ON2 = floating Connected to VBATT, VOUT1 = 2.5V ON2 = float VOUT2 = 1.8V Low-noise mode, forced fixed-frequency PWM operation. ON1 = high, ON2 = high Connected to VBATT, VOUT1 = 2.5V Connected to VL, VOUT2 = 1.8V Both outputs are enabled in normal mode. Normal operation allows automatic PWM/ PFM switchover for pulse skipping at light load, resulting in highest efficiency. — MAX1761 is in shutdown mode. _______________________________________________________________________________________ _______________________________________________________________________________________ C8 OPEN VOUT1 2.5V, 2A R1 OPEN R2 SHORT (PC TRACE) C3 220µF or 330µF 10V GND GND VL SW1-C SKIP 3 L1 7µH 1 R8 1MΩ 6 SW1-A (1.8V ON/OFF) 4 8 N1 1 6 R5 SHORT (PC TRACE) D1 OPEN P1 3 2 VBATT 7 R7 1MΩ 5 R11 OPEN SW1-B OFF/ON 2 C10 OPEN R10 SHORT 5 (PC TRACE) 4 6 4 1 2 14 15 16 C5 0.1µF ON1 ON2 FB1 5 U1 V+ REF C6 4.7µF 10V FB2 OUT2 GND DL2 CS2 DH2 C12 1µF 25V 13 VL MAX1761 3 OUT1 DL1 CS1 DH1 R9 10Ω 8 7 12 11 10 9 C7 OPEN C11 OPEN R13 OPEN R12 SHORT (PC TRACE) 4 2 5 1 8 N2 P2 6 VL 7 3 R6 SHORT (PC TRACE) D2 OPEN L2 7µH C1 10µF 25V C9 OPEN C2 OPEN C4 220µF or 330µF 10V R4 SHORT (PC TRACE) R3 OPEN VOUT2 1.8V, 2A Evaluates: MAX1761 VBATT 5V TO 20V MAX1761 Evaluation Kit Figure 1. MAX1761 EV Kit Schematic 3 Evaluates: MAX1761 MAX1761 Evaluation Kit 1.0" Figure 2. MAX1761 EV Kit Component Placement Guide— Component Side 1.0" Figure 4. MAX1761 EV Kit PC Board Layout—Ground Plane (Layer 3) 4 1.0" Figure 3. MAX1761 EV Kit PC Board Layout—Ground Plane (Layer 2) 1.0" Figure 5. MAX1761 EV Kit PC Board Layout—Solder Side _______________________________________________________________________________________ MAX1761 Evaluation Kit Figure 6. MAX1761 EV Kit Component Placement Guide— Solder Side Figure 7. MAX1761 EV Kit PC Board Layout—Component 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 _____________________ 5 © 2000 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. Evaluates: MAX1761 1.0" 1.0"