19-1182; Rev 2; 12/98 MAX745 Evaluation Kit The MAX745 evaluation kit (EV kit) is an assembled and tested PC board that implements a step-down, switching power supply designed for charging lithium-ion (LiIon) batteries. The output voltage can be set for one to four cells. The cell voltage can be set between 4.0V and 4.4V, with 0.75% accuracy, using standard 1% resistors. Two LEDs indicate the charging status. The MAX745 should be used to charge only Li-Ion battery packs. To charge other types of batteries, use the MAX1648 or the MAX712/MAX713. To charge SMBus™ smart-battery packs, use the MAX1647. ______________Component Suppliers SUPPLIER* AVX Dale-Vishay International Rectifier IRC Motorola Sanyo Sumida PHONE FAX (803) 946-0690 (402) 564-3131 (310) 322-3331 (512) 992-7900 (602) 303-5454 (619) 661-6835 (847) 956-0666 (803) 626-3123 (402) 563-6418 (310) 322-3332 (512) 992-3377 (602) 994-6430 (619) 661-1055 (847) 956-0702 ____________________________Features ♦ Charges One to Four Li-Ion Cells ♦ Low Heat/High Efficiency ♦ 300kHz PWM Operation ♦ 0.75% Overall Accuracy over Temperature ♦ 6V to 24V Input Voltage Range ♦ Proven PC Board Layout ♦ Fully Assembled and Tested ______________Ordering Information PART MAX745EVKIT TEMP. RANGE 0°C to +70°C BOARD TYPE Surface Mount *Please indicate that you are using the MAX745 when contacting these component suppliers. _____________________________________________________________Component List DESIGNATION QTY C1 1 DESCRIPTION 68µF, 20V, 0.150Ω, low-ESR tantalum capacitor AVX TPSE686M020R0150 C2, C7, C9, C12 4 0.1µF ceramic capacitors C3 1 47nF ceramic capacitor C4 1 0.22µF ceramic capacitor C5 1 4.7µF, 10V, low-ESR capacitor C6 0 Open C8, C10 2 150µF, 35V, 0.17Ω, aluminum electrolytic capacitors Sanyo 35CV150GX C11 1 1000pF ceramic capacitor 3 3A, 40V, surface-mount Schottky diodes Motorola MBRS340T3 D1, D4, D6 DESIGNATION QTY DESCRIPTION L1 1 22µH, 2.8A surface-mount inductor Sumida CDRH125-220 LED1, LED2 2 Light-emitting diodes M1 1 2A, 30V, 0.080Ω, logic-level, dual, N-channel FET International Rectifier IRF7303 R1 1 0.100Ω, 1% sense resistor Dale WSL-2010-R1F or IRC LR2010-01-R100F R2, R15 2 10kΩ, 5%, surface-mount resistors R3, R11, R12, R16 4 100kΩ, 1%, surface-mount resistors R4, R5, R10 0 Shorted R6, R7 2 1kΩ, 5%, surface-mount resistors R13 1 8kΩ, 5%, surface-mount resistor R14 1 24Ω, 5%, surface-mount resistor D2 1 1N4148-type signal diode (SOT23) U1 1 Maxim MAX745EAP J3, J4 2 Banana jacks U2 1 Maxim MAX931CSA None 1 Printed circuit board JU1, JU2, JU3 3 3-pin headers JU4 1 2-pin header SMBus is a trademark of Intel Corp. ________________________________________________________________ Maxim Integrated Products 1 For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800. For small orders, phone 1-800-835-8769. Evaluates: MAX745 _______________General Description Evaluates: MAX745 MAX745 Evaluation Kit _________________________Quick Start _______________Detailed Description Do not turn on power until all connections are complete. Observe all precautions on the battery manufacturer’s data sheet. Use only lithium-ion (Li-Ion) cells with this charger. 1) Set jumpers JU1 and JU2 to indicate the number of cells in the battery pack (Table 1). Upon insertion, batteries are fast charged at a constant current. Batteries enter float charge when the total battery terminal voltage reaches the voltage limit. 2) Set jumper JU3 to the 2A position to enable 2A output current (Table 2). 3) Make sure that jumper JU4 is open to enable charger output. 4) Connect a DC power supply with sufficient power rating across the VIN and GND banana jacks (VIN is positive, GND is negative). DC input voltage should be between 6V and 24V. 5) Connect a Li-Ion battery pack between BATT and GND (BATT is positive, GND is negative). The battery can be connected with the charger off without causing damage, or it can be connected after power is applied. 6) Turn on the DC power supply. Fast charging begins as soon as the battery is connected and the DC power supply is on. 7) When the STATUS LED turns on, the charger is operating in current-regulating mode (fast charge). When the STATUS LED turns off, the charger is operating in voltage-regulating mode (float charge). 8) When the DONE LED turns on, the charging current has fallen below the threshold set by R13, indicating that charging is over. The charger can be shut down by closing jumper JU4. LED2 (STATUS) indicates that the charger is in currentregulating mode. This signal can be used to detect the transition from fast charge to float charge. LED1 (DONE) indicates that the battery current (fast charge) is below the threshold set by R13. The IBAT output pin sources a current that is proportional to the load current, and comparator U2 detects when that load current exceeds the threshold set by R13. R13 should not cause the IBAT voltage to exceed 2V under maximum load current. See the MAX745 data sheet. Table 2. Jumper Functions JUMPER STATE JU1 3, 4 CELL1 = VL; three or four cells selected. JU1 1, 2 CELL1 = GND; one or two cells selected. JU2 2, 4 CELL0 = VL; two or four cells selected. JU2 1, 3 CELL0 = GND; one or three cells selected. JU3 2A ISET = REF; output current limited to 2A. JU3 Open ISET is open; output current limited to 1A. JU3 0A JU4 Open JU4 FUNCTION ISET = GND; output current disabled. THM = REF; output enabled. Closed THM = GND; output disabled. Table 1. Configuring Number of Lithium-Ion Cells 2 NUMBER OF CELLS VOLTAGE ADJUSTMENT RANGE JU1 POSITION JU2 POSITION 1 4V-4.4V 1, 2 1, 3 2 8V-8.8V 1, 2 2, 4 3 12V-13.2V 3, 4 1, 3 4 16V-17.6V 3, 4 2, 4 _______________________________________________________________________________________ JU4 R15 10k REF C5 4.7µF 10V C6 OPEN R11 100k 1% R3 100k 1% VL 6 5 4 C12 0.1µF C9 0.1µF REF HYST IN- IN+ JU3 0A 1A 2A R2 C2 10k 0.1µF REF R13 8k IBAT 3 R12 100k 1% R16 100k 1% 6 5 4 3 2 1 10 9 1 8 GND SETI VADJ REF U1 R7 1k VL JU2 1, 3 2, 4 VL MAX745 THM/SHDN CCI CCV VL DCIN IBAT GND OUT 7 C4 0.22µF 8 C3 47nF DCIN 2 V- MAX931 U2 V+ 7 JU1 11 12 13 14 15 16 17 18 19 1, 2 3, 4 VL CELL1 CELLO STATUS BATT CS PGND DLO DHI LX 20 D2 LED1 DONE BST R14 24Ω VL C7 0.1µF GND VIN VL 7 R6 1k LED2 STATUS PGND 2 R5 SHORT R4 SHORT R10 SHORT DCIN PGND J4 BLACK J3 RED 4 3 1 M1A 8 5 D4 D1 M1B 6 L1 22µH PGND D6 C8 150µF 35V C11 1000pF R1 0.1Ω 1% PGND PGND C10 150µF 35V BATT- C1 68µF 20V BATT+ Evaluates: MAX745 VL MAX745 Evaluation Kit Figure 1. MAX745 EV Kit Schematic Diagram _______________________________________________________________________________________ 3 Evaluates: MAX745 MAX745 Evaluation Kit 1.0" 1.0" Figure 2. MAX745 EV Kit Component Placement Guide— Component Side Figure 3. MAX745 EV Kit PC Board Layout—Component Side 1.0" Figure 4. MAX745 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 © 1998 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.