Evaluates: MAX1737 19-1884 Rev 0 12/00 MAX1737 Evaluation Kit General Description Features The MAX1737 evaluation kit (EV kit) is an assembled Complete Li+ Charging Solution for 1 to 4 Cells and tested PC board that implements a step-down, Low Heat and High Efficiency switching lithium-ion (Li+) battery charger. It can be set 300kHz PWM Operation to charge 1 to 4 series cells. The cell voltage can be set between 4.0V and 4.4V, using standard 1% resistors, Up to 28V Input Voltage Range while maintaining 1% overall regulation accuracy. 28-Pin QSOP Package The MAX1737 detects faulty cells and terminates Surface-Mount Construction charging. Two capacitors are used to set the charge Fully Assembled and Tested termination, prequalification, and fault timeout periods. Three LEDs indicate the charging status. A user-sup- Ordering Information plied thermistor can be connected to the MAX1737 EV kit to monitor battery temperature and suspend charg- PART TEMP. RANGE IC PACKAGE ing for over- and undertemperature conditions. MAX1737EVKIT 0C to +70C 28 QSOP Component List DESIGNATION QTY DESCRIPTION DESIGNATION QTY DESCRIPTION Diodes 1N4148-type 4.7 F, 10V X5R ceramic Fairchild MMSD4148, capacitor D2, D3 2 General Semiconductor C1 1 Taiyo Yuden 1N4148W, or Vishay Liteon/ LMK316BJ475ML or Diodes, Inc. 1N4148W Murata GRM42-6X5R475K10 0.1 F, 50V X7R ceramic JU1, JU3, JU4 5 2-pin headers capacitors (0805) JU2, JU5 2 3-pin headers C2, C4, C7, C10, M urata GRM4 0034X7R 104K050 5 JU6 1 4-pin header C11 or JU7, JU8 0 Not installed Taiyo Yuden UMK212BJ104KG 22 H, 2.8A inductor L1 1 0.22 F, 50V X7R ceramic Sumida CDRH124-220 capacitor LED1, LED2 2 Light-emitting diodes (green) C3 1 Taiyo Yuden LED3 1 Light-emitting diode (red) UMK316BJ224ML 0.047 F, 50V X7R ceramic Dual N-channel MOSFET C5, C6 2 N1 (N1A, N1B) 1 Fairchild FDS6990A capacitors 0.1 F, 50V X7R ceramic R1, R11 2 10k 5% resistors C8, C9 2 capacitors (1206) R2, R3, R4 3 1k 5% resistors C12, C13, C14, 1000pF, 50V X7R ceramic 6 R5R10 6 100k 1% resistors C21, C22, C23 capacitors 0.05 1%, 0.5W sense res istor 68 F, 20V, 0.150 , low-ESR Dale-Vishay WSL-2010-R050F C15 1 tantalum capacitor R12 1 or AVX TPSE686M020R0150 IRC LRC-LR2010-01-R050-F 22 F, 35V, 0.300 , low-ESR R13, R14, R19, tantalum capacitors C18, C19 2 4 4.7 5% resistors R20 AVX TPSE226M035R0300 or Kemet T495X226M035AS R15, R17 0 Not installed Schottky diodes, 3A, 40V 0.1 1%, 0.5W sense resistor Fairchild MBRS340, Dale-Vishay WSL-2512-R100F R18 1 G ener al S em i conduc tor S S 34, or D1, D4 2 Motorola MBRS340, or IRC LRC-LR2512-01-R100-F Vishay Liteon/Diodes, Inc. U1 1 MAX1737EEI B340 None 5 Shunts Maxim Integrated Products 1 For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.MAX1737 Evaluation Kit (red) lights indicate a faulty battery. This kit is shipped Quick Start with a 10k resistor to disable the temperature monitor- The MAX1737 EV kit is a fully assembled and tested ing function. If temperature monitoring is required, con- surface-mount board. Follow the steps below to verify nect the appropriate thermistor (see Jumper Selection board operation. Do not turn on the power supply section). until all connections are completed. Observe all pre- For more information on the operation of the MAX1737, cautions on the battery manufacturers data sheet. refer to the Detailed Description section of the Use only lithium-ion cells with this charger: MAX1737 data sheet. 1) Set jumper JU6 to indicate the number of cells in the battery pack (Table 1). Charging Status The three LEDs on the EV kit indicate the charging status: 2) Place a shunt on jumper JU1 to disable the temper- ature monitoring function. LED1 (FULLCHG) 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 MAX1737. LED2 (FASTCHG) indicates that the battery pack is being charged with a constant current. 4) Place a shunt across JU3 to enable 2A charging current limit. LED3 (FAULT) indicates that charging terminated abnormally. 5) Place a shunt across JU4 to enable 2A input current limit. Jumper Selection 6) Remove any shunt from JU5 to set the cell voltage Jumper JU1 connects the MAX1737 thermistor input to 4.2V. If a different battery regulation voltage is (THERM) to GND through a 10k resistor, disabling required, refer to the MAX1737 data sheet. temperature qualification. To enable temperature quali- fication (charging between 0C and 50C), remove the 7) Connect a +7VDC to +28VDC power supply with shunt from JU1, and connect a thermistor (BC Compo- sufficient power rating across the VIN and GND nents part number 2322-640-63103 or equivalent) to pads. the THERM and GND pads. For more information, refer 8) Connect a lithium-ion battery pack between the to the MAX1737 data sheet. BATT+ and BATT- pads. The MAX1737 can be placed in shutdown mode using 9) Turn on the power supply. jumper JU2. See Table 1 for jumper settings. 10) Measure the battery voltage and verify that the Jumper JU3 sets the charging current limit (current to LEDs indicate the correct state. the battery). A shunt across this jumper limits the output current to 2A. With the shunt removed, a resistor-divider Detailed Description formed by R5 and R6 sets the current. The EV kit When battery charging is initiated, the charger enters comes with the resistors selected for a 1A current limit. the prequalification state. In this state, the batteries are A different current can be selected by changing the charged at 1/20 of the programmed current limit while resistors (refer to the MAX1737 data sheet). the charger measures the battery to determine if it can Jumper JU4 sets the input current limit (current from the be charged. If the battery voltage is above 2.5V per power supply). A shunt across this jumper limits the cell, charging begins. At this time, the batteries are input current to 2A. With the shunt removed, a resistor- charged at a constant current (Fast Charge state) and divider formed by R7 and R8 sets the current. The EV a constant voltage (Full Charge state). The charger kit comes with the resistors selected for a 1A current exits the Full Charge state and enters the Top Off state limit. A different current can be selected by changing once the battery current drops to 10% of the Fast the resistors (refer to the MAX1737 data sheet). Charge current, or the Fast Charge timer expires. The charger remains in the Top Off state for 45 minutes, at Jumper JU5 sets the voltage per cell. Jumper JU6 which time charging is terminated. selects the number of series cells to be charged. See Table 1 for jumper settings. 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 sens- es a temperature below 0C or above +50C, charging suspends until the temperature returns to a safe level. If the charger is unable to enter the Fast Charge or Full Charge state, charging is terminated and the Fault LED 2 Evaluates: MAX1737