19-1816; Rev 0; 10/00 MAX1757/MAX1758 Evaluation Kits Features ♦ Complete Li+ Charging Solution up to 3-Series Cells (MAX1757) and 4-Series Cells (MAX1758) ♦ 1.5A Battery-Charging Current ♦ Low Heat/High Efficiency ♦ 300kHz PWM Operation ♦ ♦ ♦ ♦ Up to 14V Input Voltage Range (MAX1757) Up to 28V Input Voltage Range (MAX1758) 28-Pin SSOP Package Surface-Mount Construction ♦ Fully Assembled and Tested Ordering Information PART IC PACKAGE MAX1757EVKIT 28 SSOP MAX1758EVKIT 28 SSOP Component List DESIGNATION QTY DESCRIPTION C1, C2, C3, C7, C14, C17, C18 7 0.1µF, 50V X7R ceramic capacitors (0805) Murata GRM40-034X7R104K050 or Taiyo Yuden UMK212BJ104KG C4 1 1µF, 10V X7R ceramic capacitor Taiyo Yuden LMK212BJ105MG or Murata GRM40X7R105K10 C5, C6, C19 3 1000pF, 50V X7R ceramic capacitors 2 0.1µF, 50V X7R ceramic capacitors (1206) 2 22µF, 35V, 0.300Ω, low-ESR tantalum capacitors AVX TPSE226M035R0300 or Kemet T495X226M035AS C8, C9 C10, C11 C12 C13 C15 1 0.22µF, 50V X7R ceramic capacitor Taiyo Yuden UMK316BJ224ML 1 4.7µF, 10V X5R ceramic capacitor Taiyo Yuden LMK316BJ475ML or Murata GRM42-6X5R475K10 1 68µF, 20V, 0.150Ω, low-ESR tantalum capacitor AVX TPSE686M020R0150 DESIGNATION QTY DESCRIPTION 2 Diodes, 1N4148-type Fairchild MMSD4148, Vishay Liteon/Diodes, Inc. 1N4148W, or General Semiconductor 1N4148W D2, D4 2 Schottky diodes, 3A, 30V Nihon EC31QS03L or Vishay Liteon/Diodes, Inc. B330A JU1 JU2 1 1 JU3 1 L1 1 LED1, LED2 LED3 2 1 R1 1 R2, R12 R3–R6 R7, R8 R9, R10, R11 R13, R14 2 0 2 3 2 U1 1 D1, D3 2-pin header 3-pin header 3-pin header (MAX1757 EV kit) 4-pin header (MAX1758 EV kit) 22µH, 2.5A inductor Sumida CDRH104R-220NC Light-emitting diodes (green), T1 Light-emitting diode (red), T1 0.05Ω ±1%, 0.5W sense resistor Dale WSL-2010-R050F or IRC LRC-LR2010-01-R050-F 10kΩ ±5% resistors Not installed 100kΩ ±1% resistors 1kΩ ±5% resistors 4.7Ω ±5% resistors MAX1757EAI (MAX1757 EV kit) MAX1758EAI (MAX1758 EV kit) ________________________________________________________________ Maxim Integrated Products 1 For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. Evaluate: MAX1757/MAX1758 General Description The MAX1757/MAX1758 evaluation kits (EV kits) are assembled and tested PC boards that implement a step-down, switching lithium-ion (Li+) battery charger. The MAX1757 EV kit can be set to charge 1- to 3-series cells, and the MAX1758 EV kit can be set to charge 1to 4-series cells. The cell voltage can be set between 4.0V and 4.4V using standard 1% resistors while maintaining 1% overall regulation voltage accuracy. Three LEDs indicate the charging status. The MAX1757/MAX1758 EV kits detect faulty cells and terminate charging. Two capacitors are used to set the charge termination, prequalification, and fault timeout periods. A user-supplied thermistor may be connected to either EV kit to monitor battery temperature and suspend charging for over-/undertemperature conditions. Evaluate: MAX1757/MAX1758 MAX1757/MAX1758 Evaluation Kits Quick Start The MAX1757/MAX1758 EV kits are fully assembled and tested surface-mount boards. Follow the steps below to verify board operation. Do not turn on the power supply until all connections are completed. Observe all precautions on the battery manufacturer’s data sheet. Use only lithium-ion (Li+) cells with this charger: thermistor (see Jumper Selection section). If the charger is unable to enter the fast-charge or fullcharge states, charging is terminated and the fault LED (red) lights to indicate a faulty battery. For more information on the operation of the MAX1757 or MAX1758, refer to the Detailed Description sections of the MAX1757 and MAX1758 data sheets. Charging Status 1) Set jumper JU3 to indicate the number of cells in the battery pack (Table 1). The three LEDs on the EV kit indicate the charging status: 2) Place a shunt on jumper JU1 to disable the temperature monitoring functions. ♦ LED1 (FULL) indicates that the battery pack is being charged with a constant voltage. 3) Place a shunt across pins 1–2 on JU2 to enable the MAX1757 or MAX1758. ♦ LED2 (FAST) indicates that the battery pack is being charged with a constant current. 4) For the MAX1757, connect a +7VDC to +14VDC power supply with sufficient power rating across the VIN and GND pads. ♦ LED3 (FAULT) indicates that charging terminated abnormally. For the MAX1758, connect a +7VDC to +28VDC power supply with sufficient power rating across the VIN and GND pads. 5) Connect a lithium-ion (Li+) battery pack between the BATT+ and BATT- pads. 6) Turn on the power supply. 7) Verify that LEDs 1, 2, and 3 indicate the correct charging status. Detailed Description When battery charging is initiated, the charger enters the prequalification state. In this state, the batteries are charged at 1/10 of the programmed current limit while the charger measures the battery to determine if it can be charged. If the battery voltage is above 2.5V per cell, charging begins. At this time, the batteries are charged at a constant current (fast-charge state) or a constant voltage (full-charge state). The charger exits the full-charge state and enters the top-off state once the battery current drops to 10% of the fast-charge current, or the fast-charge timer expires. The charger remains in the top-off state for 45 minutes, after which charging is terminated. Once charging is terminated, if the battery voltage drops 5% from the fully charged voltage, charging automatically restarts. If at any time during charging, the thermistor input senses a temperature below 0°C or above +50°C, charging suspends until the temperature returns to a safe level. This kit is shipped with a 10kΩ resistor to disable the temperature monitoring function. If temperature monitoring is required, connect the appropriate 2 Charging Current The voltage at the ISETOUT pin sets the charging current to the battery. The MAX1757/MAX1758 EV kits are shipped with ISETOUT connected to REF. This sets the charging current to the full-scale value of 1.5A. To change the charging current to a lower value, cut the trace shorting the two pads of R3 and install resistors for R3 and R4. Use the equations below to calculate the resistor values: ICHG = (R4 / (R3 + R4)) x 1.5A R3 = ((1.5A / ICHG) - 1) x R4 Use 100kΩ for R4. Input Current The input current limit is set by sense resistor R1 and by the voltage applied to the ISETIN pin. This sets the input current limit to 2A (100mV/50mΩ). The MAX1757/MAX1758 EV kits are shipped with ISETIN connected to REF and a 50mΩ sense resistor. To change the input current limit to a lower value, cut the trace shorting the two pads of R5 and install resistors for R5 and R6. Use the equations below to calculate the resistor values: IIN = (R6 / (R5 + R6)) x 2A R5 = ((2A / IIN) - 1) x R6 Use 100kΩ for R6. To further increase the input current limit, reduce the value of sense resistor R1. _______________________________________________________________________________________ MAX1757/MAX1758 Evaluation Kits SUPPLIER JUMPER JUMPER POSITION Open JU1 JU2 FUNCTION Open before connecting a thermistor from THERM to GND pads. Closed* Bypasses THERM with a 10kΩ resistor. 1–2* SHDN = high. MAX1757/MAX1758 enabled. 2–3 SHDN = low. MAX1757/MAX1758 disabled. Open Drive SHDN pad with an external signal. 1–2* CELL = GND. Cell count = 1. 1–3 JU3 PHONE FAX AVX 803-946-0690 803-626-3123 BC Components 803-772-2500 Dale-Vishay 402-564-3131 402-563-6418 Fairchild 408-822-2000 408-822-2102 General Semiconductor 631-847-3000 631-847-3236 International Resistive Co. (IRC) 310-322-3331 310-322-3332 Kemet 408-986-0424 408-986-1442 Murata 814-237-1431 814-238-0490 Nihon 661-867-2555 661-867-2698 Sumida 847-956-0666 847-956-0702 Taiyo Yuden 408-573-4150 408-573-4159 Vishay Liteon/Diodes, Inc. 805-446-4800 805-446-4850 Note: Please indicate that you are using the MAX1757 or MAX1758 when contacting these manufacturers. CELL = VL. Cell count = 4. (MAX1758 only) 1–4 CELL = REF. Cell count = 3. Open CELL = Float. Cell count = 2. *Default position Jumper Selection Jumper JU1 connects the thermistor input (THERM) to GND through a 10kΩ resistor, disabling temperature qualification. To enable temperature qualification (charging between 0°C and +50°C), remove the shunt from JU1 and connect a thermistor (BC Components part # 2322-640-63103 or equivalent) to the THERM and GND pads. For more information, refer to the MAX1757 and MAX1758 data sheets. The EV kits can be placed in shutdown mode using jumper JU2. (See Table 1 for jumper settings.) Jumper JU3 selects the number of series cells to be charged. (See Table 1 for jumper settings.) ______________________________________________________________________________________ 3 Evaluate: MAX1757/MAX1758 Component Suppliers Table 1. Jumper Selection 4 Figure 1. MAX1757/MAX1758 EV Kit Schematic _______________________________________________________________________________________ *MAX1758 ONLY SHDN THERM R12 10k 3 2 JU2 3 * C3 0.1µF VL 1 JU1 2 1 JU3 4 R7 100k 1% R5 (SHORTED BY PCB TRACE) R3 (SHORTED BY PCB TRACE) R2 10k C2 0.1µF C1 0.1µF C6 1000pF C5 1000pF R8 100k 1% R6 OPEN R4 OPEN C4 1µF C19 1000pF 13 12 17 11 7 2 3 5 25 23 24 4 TIMER2 TIMER1 SHDN CELL VADJ ISETIN ISETOUT REF CCV CCS CCI THM 6 GND MAX1757 MAX1758 U1 FAULT FASTCHG FULLCHG BATT CS PGND VL BST LX HSD LX HSD CSSN CSSP DCIN 14 15 16 8 21 18 1 22 20 19 10 9 26 27 R9 1k R11 1k R10 1k D3 C7 0.1µF 28 C13 4.7µF VL + LED3 LED2 LED1 C11 22µF 35V D4 VL C17 0.1µF C10 22µF 35V C14 0.1µF + C9 0.1µF C8 0.1µF R14 4.7Ω R13 4.7Ω D1 C18 0.1µF L1 22µH R1 0.05Ω 1% D2 + C15 68µF C12 0.22µF GND BATT- BATT+ SYSTEM LOAD VIN Evaluate: MAX1757/MAX1758 MAX1757/MAX1758 Evaluation Kits MAX1757/MAX1758 Evaluation Kits 1.0" Figure 2. MAX1757/MAX1758 EV Kit Component Placement Guide—Component Side Figure 3. MAX1757/MAX1758 EV Kit PC Board Layout— Component Side 1.0" Figure 4. MAX1757/MAX1758 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. 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. Evaluate: MAX1757/MAX1758 1.0"