19-2594; Rev 1; 11/02 MAX1926 Evaluation Kit The MAX1926 evaluation kit (EV kit) is a complete, fully assembled and tested, single-cell lithium-ion (Li+) battery charger. The EV kit provides a 4.2V output from input as high as 12V, and delivers up to 1A charge current. A light-emitting diode (LED) indicates the cell’s charging status. The EV kit can be also used to evaluate the MAX1925, which is a single-cell Li+ battery charger with a 4.5V to 6.1V input voltage charge range. Features ♦ 5V to 12V Input Voltage Range ♦ Up to 1A Fast Charge Current ♦ LED Charge Status and Fault Indicator ♦ 12-Pin Thin QFN Package ♦ Surface-Mount Construction ♦ Fully Assembled and Tested Component List DESIGNATION QTY C1 C2 1 1 C3 1 C4 0 DESCRIPTION 10µF ±20%, 16V X5R ceramic capacitor (1210) Taiyo Yuden EMK325BJ106MN or TDK C3225X5R1C106MT 22µF ±20%, 6.3V tantalum capacitor (A case) AVX TAJA226M006R 0.1µF ±10%, 16V X7R ceramic capacitor (0603) Taiyo Yuden EMK107BJ104KA or TDK C1608X7R1C104KT or Murata GRM39X7R104K016AD Not installed, capacitor (0603) 1A, 30V Schottky diodes Nihon EP10QY03 Surface-mount LED (0805) 2-pin header D1, D2 2 D3 JU1 1 1 JU2 0 L1 1 Q1 1 R1 1 R2 1 Not installed, shorted by PC trace 10µH, 1.3A inductor Toko A915AY-100M or Sumida CDRH5D28-100 P-channel MOSFET 3-pin SOT23 Fairchild FDN360P 0.14Ω ±1%, 1/2W sense resistor (1206) IRC LR1206-01-R140-F 100kΩ ±5% resistor (0603) R3, R4 0 Not installed, resistors (0603) R5 1 U1 1 None 1 10kΩ ±5% resistor (0603) MAX1926ETC 12-pin thin QFN 4mm x 4mm, top mark AABF Shunt None 1 MAX1926 PC board Ordering Information PART TEMP RANGE IC PACKAGE MAX1926EVKIT 0°C to +70°C 12 Thin QFN 4mm x 4mm Note: To evaluate the MAX1925, request a MAX1925 free sample with the MAX1926EVKIT. Quick Start The MAX1926 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: 1) Verify that there is a no shunt across jumper JU1 (EN). 2) Connect a voltmeter across the EV kit’s BATT and GND pads. 3) Connect a 5V to 12V power supply to the VIN pad. Connect the power-supply ground to the GND pad closest to VIN. 4) Observe correct Li+ cell polarity. Connect the positive terminal of a single-cell Li+ battery to the BATT pad. Connect the negative terminal of the battery to the GND pad closest to BATT. 5) Turn on the power supply. The LED turns on if the battery voltage is below 4.2V and the charging current is above 125mA. See Table 3 for additional LED state descriptions. 6) The LED turns off once the Li+ cell has been fully charged. To evaluate the MAX1925, see the Evaluating the MAX1925 section. ________________________________________________________________ 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: MAX1925/MAX1926 General Description Evaluates: MAX1925/MAX1926 MAX1926 Evaluation Kit Component Suppliers PHONE FAX AVX SUPPLIER 843-946-0238 843-626-3123 www.avxcorp.com WEBSITE Fairchild 888-522-5372 408-882-2102 www.fairchildsemi.com IRC 361-992-7900 361-992-3377 www.irctt.com Murata 770-436-1300 770-436-3030 www.murata.com Nihon 81-33343-3411 81-33342-5407 www.niec.co.jp Sumida 847-545-6700 847-545-6720 www.sumida.com Taiyo Yuden 800-348-2496 847-925-0899 www.t-yuden.com TDK 847-803-6100 847-390-4405 www.component.tdk.com Toko 847-297-0070 847-699-1194 www.tokoam.com Note: Please indicate that you are using the MAX1925/MAX1926 when contacting these component suppliers. Detailed Description The MAX1926 EV kit is a fully assembled and tested single-cell Li+ battery charger. The EV kit contains an external P-channel MOSFET for current switching and can deliver up to 1A of current to a Li+ battery. An LED indicates the charging status of the battery. The maximum charging time is set to 3 hours with 0.1µF at C3. Jumper Selection In the MAX1926, EN is internally pulled to 3V with an internal 300kΩ resistance. When jumper JU1 is open, EN goes to 3V and the charger is enabled. When JU1 is shorted, EN is 0V and the charger is disabled. See Table 1 for JU1 functions In the MAX1925, EN does not have an internal pullup and must be driven high (5.5V max) or low. Extra pads (R3 and R4) are provided so that EN can be driven from a voltage-divider connected to a higher voltage without exceeding the 5.5V limit. Jumper JU2 provides options to connect THRM to a thermistor or a 10kΩ resistor. The MAX1926 is disabled when Table 1. JU1 Functions SHUNT LOCATION LED States The LED on the EV kit is driven by the CHG pin. Depending on the Li+ cell’s charging status, the pin is low or high impedance, thus turning the LED on or off. The LED blinks at 0.5Hz when the MAX1926 enters Fault Prequal1, Fault Prequal 2, Fault Full, Fault BATT Voltage, or the Fault Temp state. For driving logic circuits, remove the LED and install a pullup resistor from a logic supply to CHG. Table 3 lists the LED states. Evaluating the MAX1925 To evaluate the MAX1925, replace the MAX1926ETC with a MAX1925ETC. Install 100kΩ resistors R3 and R4 to enable the IC. Table 2. JU2 Functions EN PIN MAX1926 OUTPUT Installed Connected to GND MAX1926 is disabled Not installed EN internally pulled to 3V 2 the resistance connected to THRM is greater than 28.69Ω or less than 3.967kΩ. The MAX1926 EV kit comes with THRM connected to a 10kΩ resistor. JU2 is not populated and is shorted by a PC trace. To connect a thermistor to the EV kit, cut open the PC trace shorting JU2. Table 2 lists JU2 functions. MAX1926 is enabled JUMPER STATE THRM PIN MAX1926 OUTPUT Open Connected to a thermistor using THRM pad MAX1926 enabled with valid THRM resistance and EN high Shorted (by Default) Connect to a 10kΩ pulldown resistor MAX1926 is enabled if EN is high _______________________________________________________________________________________ MAX1926 Evaluation Kit Evaluates: MAX1925/MAX1926 Table 3. LED States CHARGING STATE CONDITION LED STATE Off EN low, or no battery, or no wall power. Prequal1 Charge current = 4mA until BATT reaches 2V. Off. On. Prequal2 Charge current = C/10 (100mA) until BATT reaches 3V. On. Fast Charge Charge current = C = 142mV/R1 (1A). On. Full Charge Charge current has fallen to C/8 (125mA). Off. Fault Prequal1 BATT does not reach 2V before Prequal1 timeout. Fault Prequal2 BATT does not reach 3V before Prequal2 timeout. Fault Full Charge current does not drop to C/8 (125mA) before fullcharge timeout. Fault Batt Voltage Battery voltage has exceeded 4.35V. Fault Temp Temperature has risen above +50°C or fallen below 0°C if a thermistor is installed. Temp fault clears by itself. None Initial power-up or enable with no battery. VIN GND S Q1 R2 100kΩ D3 ACON R3 OPEN 12 11 IN INP 4 MAX1925: Off. MAX1926: Blinking at 0.5Hz. Blinking at rapid rate as charger cycles through Reset, Prequal1, and Done. D1 C1 10µF 16V Blinking at 0.5Hz. Clear fault by cycling input power, THRM, or EN. L1 10µH D D2 G 10 EXT CS ACON 6 U1 1 R4 OPEN 5 C3 0.1µF EN 2 THRM JU1 JU2 SHORTED BY PC TRACE 3 CHG CT EN THRM R1 0.14Ω 1% MAX1926 BATT PGND GND 7 9 C2 22µF 6.3V BATT GND 8 C4 OPEN R5 10kΩ Figure 1. MAX1926 EV Kit Schematic _______________________________________________________________________________________ 3 Evaluates: MAX1925/MAX1926 MAX1926 Evaluation Kit Figure 2. MAX1926 EV Kit Component Placement Guide—Top Silkscreen Figure 3. MAX1926 EV Kit PC Board Layout—Component Side Figure 4. MAX1926 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 © 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.