19-3335; Rev 0; 7/04 MAX1575 Evaluation Kit The MAX1575 evaluation kit (EV kit) is a fully assembled and tested circuit for evaluating the MAX1575 white LED 1x/1.5x charge pump. The MAX1575 drives 4 white LEDs in a main display group and 2 white LEDs in a sub-group. These 6 surface-mount white LEDs are included on the EV kit. In addition to the LED driver circuit, the EV kit includes two pulse-generator circuits on the left side of the PC board that are used for testing the single-wire serial pulse-dimming feature of the MAX1575. Features ♦ Powers 4 Main and 2 Sub-Display LEDs ♦ Average 85% Efficiency (PLED / PBATT) over Li+ Battery Discharge ♦ 1.5% LED Current Matching ♦ Adaptive 1x/1.5x Mode Switchover ♦ Low Input Ripple and EMI ♦ Individual 5% to 100% Brightness Single-Wire Serial Pulse Dimming ♦ 2.7V to 5.5V Supply Voltage Range Component List DESIGNATION QTY DESCRIPTION ♦ Thin QFN 4mm x 4mm IC Package ♦ Fully Assembled and Tested 4 1µF ±20%, 6.3V X5R ceramic capacitors (0402) Panasonic ECJ0EB0J105M or TDK C1005X5R0J105M or equivalent 2 2.2µF ±10%, 6.3V X5R ceramic capacitors (0603) Panasonic ECJ1VB0J225K or TDK C1608X5R0J225K or equivalent C6, C7 2 0.01µF ±10%, X7R ceramic capacitors (0402) TDK C1005X7R1E103K or equivalent D1–D6 6 White surface-mount right-angle LEDs Nichia NSCW215T D7, D8 2 Diodes (SOD-323) Central CMDD4448 JU1 0 Not installed, PC board short JU2, JU3 2 3-pin headers R1 1 6.81kΩ ±1% resistor (0402) R2, R3 2 10kΩ ±5% resistors (0402) 5) Connect the power supply ground terminal to the pad on the EV kit labeled GND. S1, S2 2 Momentary pushbutton switches Panasonic EVQ-PHP03T 6) Turn on the power supply and verify that the LEDs are lit. U1 1 Maxim MAX1575ETE (16 thin QFN 4mm x 4mm) See the Detailed Description section for testing the dimming and shutdown features. U2, U3 2 MAX6818EUS-T (4-pin SOT143) — 2 Shunt, 2 position C1–C4 C5, C8 Ordering Information PART TEMP RANGE IC PACKAGE MAX1575EVKIT 0°C to +70°C 16 Thin QFN (4mm x 4mm) Quick Start Recommended Equipment A 2.7V to 5.5V power supply or battery capable of delivering 200mA. Procedure Follow the steps below to verify board operation. 1) Verify that shunts are connected across pins 1-2 of jumpers JU2 and JU3. 2) Preset the power supply to between 2.7V and 5.5V. 3) Turn off the power supply. Do not turn on the power supply until all connections are completed. 4) Connect the positive power supply terminal to the pad on the EV kit labeled IN. ________________________________________________________________ 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: MAX1575 General Description Evaluates: MAX1575 MAX1575 Evaluation Kit Component Suppliers SUPPLIER PHONE Central Semiconductor 631-435-1110 WEBSITE www.centralsemi.com Kamaya 260-489-1533 www.kamaya.com Murata 814-237-1431 www.murata.com Nichia 248-352-6575 www.nichia.com Panasonic 714-373-7939 www.panasonic.com Taiyo Yuden 408-573-4150 www.t-yuden.com TDK 847-803-6100 www.component.tdk.com Vishay 402-563-6866 www.vishay.com Note: Indicate that you are using the MAX1575 when contacting these component suppliers. Detailed Description LED Dimming To test the dimming feature, press the button labeled DIM MAIN or DIM SUB. Each of the first nine button presses dims the corresponding group of LEDs by 10%. The tenth press dims the LEDs by 5%, and the eleventh press returns the LEDs to full brightness. Refer to the MAX1575 data sheet for more information on the dimming feature. Using External Pulse Generators for Dimming To use external pulse generators in place of the pulse generators included with the EV kit, simply connect the outputs of the external pulse generators to EN_MAIN for the main display dimming, and EN_SUB for the subdisplay dimming. The grounds of the external pulse generators should be connected to the EV kit pad labeled GND. Short pins 1-2 of jumpers JU2 and JU3. Note that there are 10kΩ pullup resistors from EN_MAIN and EN_SUB to IN on the EV kit. Adjusting the 100% Brightness Level The full-brightness LED current is adjusted by changing the resistor R1. Calculate the value of R1 with the following equation, where ILED_ is the current through one of the LEDs with the dimming set to 100%. R1 = 2 Shutdown Two jumpers are included on the EV kit for shutting down each of the displays. To turn off the main LED group, short pins 2-3 of JU2. To turn off the sub-LED group, short pins 2-3 of JU3. Note that with pins 2-3 of JU2 or JU3 shorted, power is disconnected from the corresponding pulse-generator circuit on the left side of the board. To place the MAX1575 in low-power shutdown mode and disconnect power from both pulsegenerator circuits, short pins 2-3 of both JU2 and JU3. Changing the Number of LEDs The EV kit comes with 6 LEDs installed, 4 for the main display and 2 for the sub-display. To use fewer LEDs, locate the small pad next to the LED to be removed and connect it to the pad on the EV kit labeled IN. Connecting External LEDs To connect external LEDs to the MAX1575 EV kit, cut the trace shorting JU1. Connect the anodes of all the external LEDs to the small pad labeled OUT. Connect the cathodes to the small pads next to D1–D6 (D1–D4 for the main LEDs, D5–D6 for the sub-LEDs). Connect any unused pads (D1–D6) to IN. 0.6V × 234 ILED_ _______________________________________________________________________________________ MAX1575 Evaluation Kit 1 2 3 JU2 C5 2.2µF 4 VCC 2 U2 OUT IN C8 2.2µF VCC 2 U3 OUT IN MAX6816 S2 GND 1 14 IN R3 10kΩ 12 5 1 2 3 4 R1 6.81kΩ D8 13 C1P C3 1µF JU3 4 16 D7 C6 0.01µF GND 1 C1 1µF IN 3 MAX6816 S1 R2 10kΩ IN 3 OUT C1N IN OUT LED1 GND U1 ENM LED2 ENS MAX1575 LED3 LED4 SET 3 LED5 C7 0.01µF LED6 C2P EN_SUB Evaluates: MAX1575 EN_MAIN GND IN C4 1µF 2 JU1 11 D1 10 D2 9 D3 8 D4 7 D5 6 D6 C2N 1 15 C2 1µF Figure 1. MAX1575 EV Kit Schematic _______________________________________________________________________________________ 3 Evaluates: MAX1575 MAX1575 Evaluation Kit Figure 2. MAX1575 EV Kit Component Placement Guide— Component Side Figure 3. MAX1575 EV Kit Layout—Component Side Figure 4. MAX1575 EV Kit 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 © 2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.