MIC2287-3-LED-EV

MIC2287 (MLF™) Evaluation Board   1.2MHz PWM White LED Driver           General Description The MIC2287 is a small 1.2MHz constant frequency PWM white LED driver. The MIC2287 is available in either a Thin SOT-23 or a 2mm x 2mm MLF™ package. High power densities in a very small size are achieved using its internal 34V/500mA switch.   Requirements   The MIC2287 evaluation board requires an input power source that is able to deliver greater than 500mA at 2.5V.   Precautions The evaluation board does not have reverse polarity protection. Applying a negative voltage to the VIN terminal may damage the device.       LED Current Setting The LED current (ILED) is equal to the feedback voltage (95mV typical) divided by the R1 resistance value. To increase the LED current, the R1 resistor value must be reduced. Conversely, to decrease the LED current the R1 resistor value must be increased. The LED current can be calculated as follows:   95mV ILED = R1   The evaluation board is preset for ~15mA of LED current. The evaluation board can easily be modified to yield the desired LED current by replacing the R1 resistor value. The MIC2287 evaluation board is tailored for a Li-Ion range input supply voltage. It should not exceed 10V on the input.   Getting Started 1. Connect an external supply to VIN. Apply desired input voltage to the VIN (J1) and ground (J2 and J6) terminals of the evaluation board, paying careful attention to polarity and supply voltage (2.5V≤VIN≤10V). An ammeter may be placed between the input supply and the VIN terminal to the evaluation board. Ensure that the supply voltage is monitored at the VIN terminal. The ammeter and/or power lead resistance can reduce the voltage supplied to the input.   2. Enabling the MIC2287. Apply a 1.5V or greater voltage source to the enable (J3) terminal.                           MLF and MicroLeadFrame are a registered trademark of Amkor Technology. Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax 1 (408) 474-1000 • http://www.micrel.com M9999-052005 May 2005 (408) 955-1690         Micrel, Inc. MIC2287 (MLF™) Evaluation Board           L1 10µH J1 VIN   2 C1 1µF LED1 VIN SW LED2   3 1 U1 MIC2287-15BML 6 EN FB   R2     7 OVP J3 EN   D1 PGND 8       L1 10µH J1 VIN J4 VOUT   C2 1µF 2 C1 1µF VIN J3 EN 3   R5 J4 VOUT C2 1µF   LED4     PGND   LED3   8 4 LED2     1 U1 MIC2287-34BML 6 EN FB R2 AGND LED1 SW OVP LED3   7       D1 LED5   AGND 4 LED5             J6 DAC J2 GND   R1   J5 GND R1 J6 DAC     J2 GND J5 GND   3 LED Configuration 6 LED Configuration         Bill of Material MIC2287 Evaluation Board Ref Des                                               Part Number GRM185R61A105KE36D C1 C1608X5R1A105K   GRM216R61E105KA12D   VJ0805Y105KXXAT C2 C2012X5R1E105K D1 CMDSH-3   LQH32CN100K33 L1 VLF3010AT-100MR49 LED1→6 TLMW3101-GS08 R1 CRCW06036R34FRT1 R2 CRCW06032002FRT1 R3 CRCW06031001FRT1 R4 CRCW06032002FRT1       R5 CRCW06030000FRT1   MIC2287BML-15BML MIC2287BML-34BML U1 Description 1µF 10V Ceramic Capacitor, Size 0603 1µF 10V Ceramic Capacitor, Size 0603 1µF 25V Ceramic Capacitor, Size 0805 1µF 25V Ceramic Capacitor, Size 0805 1µF 25V Ceramic Capacitor, Size 0805 100mA 30V Schottky Diode 10µH 450mA Inductor 10µH 490mA Inductor 20mA White LED 6.34Ω Resistor, Size 0603 20kΩ Resistor, Size 0603 1kΩ Resistor, Size 0603 20kΩ Resistor, Size 0603   0Ω Resistor, Size 0603 (For 3 LEDs) OPEN (For 6 LEDs) 1.2MHz PWM White LED Driver w/ 15V OVP 1.2MHz PWM White LED Driver w/ 34V OVP Manufacturer Murata TDK Murata Vishay TDK Central Semi Murata TDK Vishay Vishay Vishay Vishay Vishay Vishay Micrel Micrel Notes:   1. Murata: www.murata.com 2. TDK: www.tdk.com 3. Vishay: www.vishay.com 4. Central Semiconductor: www.centralsemi.com 5. Micrel, Inc.: www.micrel.com May 2005 2 M9999-052005 (408) 955-1690   Micrel, Inc. MIC2287 (MLF™) Evaluation Board         Printed Circuit Board Layout                                       Figure 1a. Top Silkscreen Figure 1b. Top Layer Figure 1c. Bottom Silkscreen Figure 1d. Bottom Layer                                         May 2005 3 M9999-052005 (408) 955-1690   Micrel, Inc. MIC2287 (MLF™) Evaluation Board                                                                                                         MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http:/www.micrel.com   This information furnished by Micrel in this data sheet is believed to be accurate and reliable. However no responsibility is assumed by Micrel for its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer. Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser's use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser's own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale.     © 2005 Micrel, Inc. May 2005 4 M9999-052005 (408) 955-1690