MAX1575

19-3335; Rev 0; 7/04 MAX1575 Evaluation Kit General Description 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 ♦ Thin QFN 4mm x 4mm IC Package ♦ Fully Assembled and Tested Evaluates: MAX1575 Component List DESIGNATION QTY DESCRIPTION 1µF ±20%, 6.3V X5R ceramic capacitors (0402) Panasonic ECJ0EB0J105M or TDK C1005X5R0J105M or equivalent 2.2µF ±10%, 6.3V X5R ceramic capacitors (0603) Panasonic ECJ1VB0J225K or TDK C1608X5R0J225K or equivalent 0.01µF ±10%, X7R ceramic capacitors (0402) TDK C1005X7R1E103K or equivalent White surface-mount right-angle LEDs Nichia NSCW215T Diodes (SOD-323) Central CMDD4448 Not installed, PC board short 3-pin headers 6.81kΩ ±1% resistor (0402) 10kΩ ±5% resistors (0402) Momentary pushbutton switches Panasonic EVQ-PHP03T Maxim MAX1575ETE (16 thin QFN 4mm x 4mm) MAX6818EUS-T (4-pin SOT143) Shunt, 2 position C1–C4 4 Ordering Information PART MAX1575EVKIT TEMP RANGE 0°C to +70°C IC PACKAGE 16 Thin QFN (4mm x 4mm) C5, C8 2 Quick Start Recommended Equipment A 2.7V to 5.5V power supply or battery capable of delivering 200mA. C6, C7 2 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. 5) Connect the power supply ground terminal to the pad on the EV kit labeled GND. 6) Turn on the power supply and verify that the LEDs are lit. See the Detailed Description section for testing the dimming and shutdown features. D1–D6 6 D7, D8 JU1 JU2, JU3 R1 R2, R3 S1, S2 U1 U2, U3 — 2 0 2 1 2 2 1 2 2 ________________________________________________________________ Maxim Integrated Products 1 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. MAX1575 Evaluation Kit Evaluates: MAX1575 Component Suppliers SUPPLIER Central Semiconductor Kamaya Murata Nichia Panasonic Taiyo Yuden TDK Vishay PHONE 631-435-1110 260-489-1533 814-237-1431 248-352-6575 714-373-7939 408-573-4150 847-803-6100 402-563-6866 WEBSITE www.centralsemi.com www.kamaya.com www.murata.com www.nichia.com www.panasonic.com www.t-yuden.com www.component.tdk.com 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 10k Ω pullup resistors from EN_MAIN and EN_SUB to IN on the EV kit. 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. 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 = 0.6V × 234 ILED_ 2 _______________________________________________________________________________________ MAX1575 Evaluation Kit Evaluates: MAX1575 IN 1 2 3 EN_MAIN GND IN C1 1µF 16 C1P 14 C3 1µF IN 13 C1N OUT LED1 2 11 D1 OUT C4 1µF JU1 JU2 4 VCC 2 C5 2.2µF IN R2 10kΩ D7 U2 IN OUT 3 C6 0.01µF MAX6816 S1 GND 1 12 GND IN 1 2 3 5 4 R1 6.81kΩ ENM U1 LED2 10 D2 JU3 4 VCC 2 C8 2.2µF ENS MAX1575 LED3 9 D3 R3 10kΩ D8 3 SET LED4 LED5 8 7 6 D4 D5 D6 U3 IN OUT 3 C7 0.01µF C2P EN_SUB 1 C2 1µF MAX6816 S2 GND 1 LED6 C2N 15 Figure 1. MAX1575 EV Kit Schematic _______________________________________________________________________________________ 3 MAX1575 Evaluation Kit Evaluates: MAX1575 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.