LX1995 EVALUATION GUIDE MINIATURE LED DRIVER LX1995 EVUALATION KIT I N T E G R A T E D Copyright © 2004 Rev. 1.0, 2004-08-13 P R O D U C T S Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 1 LX1995 EVALUATION GUIDE TABLE OF CONTENTS LX1995 EVAL Introduction .............................................................................................................................. ..3 Schematic for LX1995 Evaluation Board ............................................................................................................... 4 Hook up.................................................................................................................................................................. 5 Connections ........................................................................................................................................................... 6 Printed Circuit Board .............................................................................................................................................. 7 Bill of Materials....................................................................................................................................................... 8 Copyright © 2004 Rev. 1.0, 2004-08-13 Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 2 LX1995 EVALUATION GUIDE INTRODUCING TO PRODUCT The LX1995 Evaluation Board (EB) is available from Microsemi for evaluating the performance of the LX1995 LED driver integrated circuit. (See picture 1) The EB contains a small amount of support circuitry that enhances performance in different dimming configurations. (See schematic 1.) In a typical application, some of this circuitry would be eliminated. KEY FEATURES OF THE LX1995 • • • • • • • • • < 1µA Shutdown Current > 85% Maximum Efficiency Efficient at Low Current Levels < 70µA Quiescent Supply Current in Operating Mode VIN Range 1.6V to 5.5V Logic Controlled Shutdown Dimming Options: PWM or Varying DC Voltage Tiny 5-Pin TSOT Package Smallest External Components APPLICATIONS • • • • • • Pagers Wireless Phones PDAs LED Driver Digital Camera Displays GPS Receivers PART SPECIFIC INFORMATION Part Number Switch Current LX1995-1CSG LX1995-1CSE LX1995-2CSG LX1995-2CSE Description 325mA High Efficiency LED Driver 500mA Table 1 – Part Information IC EVALUATION BOARDS LX1995-1CSG LX1995-1SG EVAL LX1995-1CSE LX1995-1SE EVAL LX1995-2CSG LX1995-2SG EVAL LX1995-2CSE LX1995-2SE EVAL Table 2 – Evaluation Board Information Copyright © 2004 Rev. 1.0, 2004-08-13 Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 3 LX1995 EVALUATION GUIDE SCHEMATIC FOR LX1995 EVAL D1 UPS5817 L1 10µH JU1 VIN VOUT C2 1µF U1 LX1995 GND R1 100K SW IN C1 10µF SHDN GND OPT T-1.75 LED1 OPTIMITE OPT T-1.75 LED2 OPTIMITE OPT T-1.75 LED3 OPTIMITE OPT T-1.75 LED4 OPTIMITE FB GND SHDN R8 100K DC_ADJ GND R3 90.9K R5 9.09K PWM_ADJ GND R2 11.3K C3 0.1µF R4 15 Figure 1 – Evaluation Board Schematic Copyright © 2004 Rev. 1.0, 2004-08-13 Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 4 LX1995 EVALUATION GUIDE 2. Connect a 3.6V typical 1A power source between VIN and GND terminals. 3. Apply a 1.5V DC signal to the DC_ADJ terminal. Signal GND can be referenced to GND2 for convenience. 4. Vary the DC signal from 0V to 3V and observe the LEDs dimming. (Measure LED current from LED4 cathode to GND2 if desired. I = V / 15. LX1995 EVALUATION HOOK UP The following is a demonstration scenario that can be used to evaluate the LX1995: Directions for hook up (DC dimming mode): 1. Install jumper JU1. + LED3 LED2 LED1 GND 0V GND4 VOUT GND3 R4 R8 R2 R3 C3 R5 D1 C2 PWM_ADJ R1 GND2 3.3V U1 JU1 VIN C1 /SHDN PWM <1KHz LED4 - DC_ADJ DC DIMMER 0V to 3V ( DIMMING OPTION 1) 3.3V 0V L1 PWM >5KHz (800) 877-6458 ( DIMMING OPTION 3) POWER 3.6V + - LX1995 MINIATURE LED DRIVER EVALUATION BOARD ( DIMMING OPTION 2) Figure 2 – Typical Hook Up for the LX1995 Eval Board Copyright © 2004 Rev. 1.0, 2004-08-13 Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 5 LX1995 EVALUATION GUIDE CONNECTIONS The LX1995 Evaluation Board has 9 test lead attachment point for applying power and dimming inputs or for monitoring voltages. Function Board Label Connection Input Power VIN Power supply (3.55V+/- 1.95V). Power Ground GND Common power supply ground. Enable DC dimming Connect to GND to disable LX1995. A <1KHz logic PWM signal can also be applied. /SHDN DC_ADJ Apply a 0 to 3V DC dimming input PWM dimming PWM_ADJ Apply a >5KHz 3.3V logic PWM signal. Output Voltage VOUT Test point to monitor voltage across all LEDs. Signal Ground GND# Multiple common grounds for probes. etc Table 3 – Connection Points Hints: For best results, use only one of the three possible LED dimming methods at a time. LED current can be monitored by measuring the voltage from LED4 cathode to GND and dividing by 15 (the value of R4). NOTE: Jumper JU1 must be connected for the LX1995 to function. This jumper can be replaced with a wire loop so the inductor current waveform can be observed using a current probe. Copyright © 2004 Rev. 1.0, 2004-08-13 Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 6 LX1995 EVALUATION GUIDE U1 D1 GND4 VOUT GND3 C2 PWM_ADJ R4 R8 R2 R3 C3 R5 LED1 DC_ADJ LED2 JU1 GND LED3 C1 /SHDN VIN LED4 R1 GND2 PRINTED CIRCUIT BOARD LAYOUT L1 (800) 877-6458 LX1995 MINIATURE LED DRIVER EVALUATION BOARD Figure 3 – LX1995 Evaluation Board Copyright © 2004 Rev. 1.0, 2004-08-13 Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 7 LX1995 EVALUATION GUIDE BILL OF MATERIALS MISCELLANEOUS COMPONENTS Line Item Part Description 1 Miniature LED Driver 2 LED, White 3 Diode, Schottky, 20V, 1A 4 Inductor, 10µH 5 Jumper 6 3-Pin Header, .100 7 Lead Attachment HW x – denotes switch current yy – denotes Package Type Manufacturer & Part # MICROSEMI MICROSEMI MICROSEMI COILCRAFT LX1995-xCyy UPWLED UPS5817 LPO3310-103MX Case 0603 Powermite Reference Designators U1 LED# D1 L1 Qty 1 4 1 1 1 1 9 CAPACITORS Line Item 1 2 3 Part Description Capacitor, 10µF, 6.3V, X5R Capacitor, 1.0µF, 50V, X7R Capacitor, 0.1µF, 50V, X7R Part Description MURATA MURATA MURATA GRM319R60J106ME01D C3216X7R1H105K GRM21BR71H104KA01L Case Reference Designators Qty 1206 1206 0805 C1 C2 C3 1 1 1 Case Reference Designators Qty 0603 0603 0603 0805 0603 R1, R8 R2 R3 R4 R5 2 1 1 1 1 RESISTORS Line Item 1 2 3 4 5 Part Description Resistor, 100K Resistor, 11.3K Resistor, 90.9K Resistor, 15 Resistor, 9.09K Copyright © 2004 Rev. 1.0, 2004-08-13 Part Description PANASONIC PANASONIC PANASONIC PANASONIC PANASONIC ERJ-3EKF1003V ERJ-3EKF1132V ERJ-3EKF9092V ERJ-6ENF15R0V ERJ-3EKF9091V Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 8