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| 19-3334; Rev 0; 7/04 MAX1574 Evaluation Kit General Description The MAX1574 evaluation kit (EV kit) is a fully assembled and tested circuit for evaluating the MAX1574 white LED 1x/2x charge pump. The EV kit comes with 3 white surface-mount LEDs installed. A pulse generator circuit is provided on the EV kit for easy evaluation of the single-wire serial pulse-dimming feature of the MAX1574. The pulse generator also has a flash setting for flashing the LEDs at full brightness. Features Up to 180mA (60mA/LED) Drive Capability 83% Average Efficiency (PLED / PBATT) over Li+ Battery Discharge 0.6% LED Current Matching Adaptive 1x/2x Mode Switchover Low Input Ripple and EMI 5% to 100% Single-Wire Serial Pulse Dimming 0.1A Low Shutdown Current Evaluates: MAX1574 Ordering Information PART MAX1574EVKIT TEMP RANGE 0C to +70C IC PACKAGE 10 TDFN (3mm x 3mm) 2.7V to 5.5V Supply Voltage Range 10-Pin, 3mm x 3mm TDFN Package Fully Assembled and Tested Component List DESIGNATION QTY DESCRIPTION 0.22F 10%, 6.3V X5R ceramic capacitor (0402) TDK C1005X5R0J224K Taiyo Yuden JMK105BJ224KV or equivalent 1F 20%, 6.3V X5R ceramic capacitors (0402) TDK C1005X5R0J105M Panasonic ECJ0EB0J105M or equivalent 2.2F 10%, 6.3V X5R ceramic capacitor (0603) TDK C1608X5R0J225K Panasonic ECJ1VB0J225K or equivalent 1000pF 10%, 25V X7R ceramic capacitor (0402) TDK C1005X7R1E102K or equivalent 0.15F 10%, X7R ceramic capacitor (0402) TDK C1005X5R0J154K or equivalent White surface-mount right-angle LEDs Nichia NSCW215T DESIGNATION QTY D4 JU1 JU2 JU3 R1 R2 R3 R4 S1 1 1 1 0 1 1 1 1 1 DESCRIPTION Diode (SOD-323) Central Semiconductor CMDD4448 3-pin header Not installed, PC board short Not installed, PC board open 13.7k 1% resistor (0402) 4.42k 1% resistor (0402) 10k 5% resistor (0402) 1 5% resistor (0805) Momentary pushbutton switch Panasonic EVQ-PHP03T DPDT, vertical 9mm x 3.5mm slide switch Panasonic ESD11V220 Maxim MAX1574ETB (10 TDFN 3mm x 3mm) MAX6816EUS-T (4-pin SOT143) MAX6422XS23-T (4-pin SC70) MAX1574 EV kit PC board Shunt, 2 position C1 1 C2, C3 2 C4 1 S2 1 C5 1 U1 U2 U3 -- -- 1 1 1 1 1 C6 1 D1, D2, D3 3 ________________________________________________________________ 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. MAX1574 Evaluation Kit Evaluates: MAX1574 Component Suppliers SUPPLIER Central 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 3) Turn on the power supply and preset to between 2.7V and 5.5V. 4) Turn the power supply off. Do not turn on the power supply until all connections are completed. 5) Connect the positive power-supply lead to the EV kit terminal labeled IN. 6) Connect the power-supply ground to the EV kit terminal labeled GND. 7) Turn the power supply on. The LEDs will flash once. This is due to the pulse generator circuit powering up and not the MAX1574. 8) Press switch S1 to flash the LEDs. Note: Indicate that you are using the MAX1574 when contacting these component suppliers. Detailed Description LED Dimming To test the dimming feature, set switch S2 to the DIM position and press button S1 to dim the LEDs. Each of the first nine button presses dims the LEDs by 10%. The tenth press dims the LEDs by 5%, and the eleventh press returns the LEDs to full brightness. Refer to the MAX1574 data sheet for more information on the dimming feature. Quick Start Recommended Equipment * A 2.7V to 5.5V power supply or battery capable of delivering 400mA. Procedure Follow the steps below to verify board operation. Dimming 1) Verify that jumper JU1 is shorted between pins 1-2. 2) Set switch S2 to the DIM position (indicated on the EV kit PC board). 3) Turn on the power supply and preset to between 2.7V and 5.5V. 4) Turn the power supply off. Do not turn on the power supply until all connections are completed. 5) Connect the positive power-supply lead to the EV kit terminal labeled IN. 6) Connect the power-supply ground to the EV kit terminal labeled GND. 7) Turn the power supply on. 8) The LEDs should be lit at full brightness. 9) To test the dimming feature, press button S1 to reduce the LEDs' brightness to 90%. Press S1 again to further reduce the LEDs' brightness. See the LED Dimming section for more information. Flash 1) Verify that jumper JU1 has pins 1-2 shorted. 2) Set switch S2 to the FLASH position (indicated on the EV kit PC board). Using an External Pulse Generator for Dimming To use an external pulse generator in place of the pulse generator included on the EV kit, simply connect the output of the pulse generator to the pad labeled EN. Connect the ground of the pulse generator to the EV kit pad labeled GND. Set S2 to the DIM position. Remove the shunt from JU1 when using a logic-level pulse generator, or short pins 1-2 of JU1 to provide a 10k pullup resistor from EN to IN when driving EN with an opendrain output. Refer to the MAX1574 data sheet for a timing diagram. Adjusting the 100% Brightness Level The LED current is adjusted by changing the value of resistor R1. Calculate the value of R1 with the following equation, where ILED_ is the current through one of the LEDs with no dimming (100% brightness): R1 = 0.6V x 393 ILED _ Adjusting the Flash Brightness Level To test the flash, set switch S2 to the FLASH position and press button S1 to flash the LEDs. 2 _______________________________________________________________________________________ MAX1574 Evaluation Kit To adjust the brightness of the flash, replace resistor R2. Calculate the value of R2 from the following equation, where ILED_ is the flash current through one of the LEDs: R2 = 0.6V x 393 ILED _ Connecting External LEDs To connect external LEDs to the MAX1574 EV kit, cut the trace shorting JU2. Connect the anodes of all the external LEDs to the pad labeled OUT. Connect the cathodes to the pads labeled LED_. Connect all unused LED_ pads to IN. Evaluates: MAX1574 Input Filtering Shutdown The MAX1574 EV kit comes assembled with a 1 input filtering resistor to ensure stable operation when powering the EV kit with long leads from a noisy power source. JU3 is provided to short this 1 resistor for evaluation purposes. Short JU3 when powering the MAX1574 EV kit from a battery. To turn off the LEDs and place the EV kit in low-power shutdown mode, short pins 2-3 of JU1. To enable the circuit, short pins 1-2 of JU1. To control enable/shutdown with an external logic signal, short pins 1-2 of JU1 (providing a 10k pullup resistor), or remove the shunt from JU1 (no pullup) and connect the digital control signal to the pad labeled EN. Changing the Number of LEDs The EV kit comes with 3 white surface-mount LEDs installed. To use fewer LEDs, connect the pad labeled LED_ (corresponding to any unused LED) to the pad labeled IN. 2.7V TO 5.5V JU1 1 2 3 R3 10k D4 IN C1 0.22F UP TO 180mA C3 1F OUT 4 VCC U2 2 IN C4 2.2F EN GND R4 1 3 JU3 1 C2 1F 9 2 IN GND EN CP U1 4 CN OUT 10 JU2 MAX6816 GND 1 OUT 3 C5 1000pF MAX1574 LED1 8 D1 LED1 S1 1 3 4 6 C6 0.15F R1 13.7k R2 4.42k 2 S2-A 5 S2-B 5 LED2 SET LED3 7 D2 LED2 1 VCC U3 RESET 4 6 D3 LED3 2 MAX6422XS 23-T GND SRT 3 Figure 1. MAX1574 EV Kit Schematic _______________________________________________________________________________________ 3 MAX1574 Evaluation Kit Evaluates: MAX1574 Figure 2. MAX1574 EV Kit Component Placement Guide-- (Component Side) Figure 3. MAX1574 EV Kit Layout--Component Side Figure 4. MAX1574 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 (c) 2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. |
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