IS31LT3505-SLS2-TR

IS31LT3505 1.0MHZ BOOST CONVERTER WITH 35V INTERNAL NMOS July 2014 GENERAL DESCRIPTION FEATURES The IS31LT3505 is a constant current step-up converter with internal NMOS. The step-up converter topology allows series connection of the white LEDs so the LED currents are identical for uniform brightness as well as constant output voltage to drive other devices. The output current of each channel can be set by an external resistor and dimming the brightness of LEDs with the PWM signal or DC voltage. The IS31LT3505 operates with a switching frequency up to 1MHz. A low 0.3V feedback voltage minimizes power loss in the current setting resistor for better efficiency. With OVP circuit, the chip and the system can be safe even if the load is not connected.          IS31LT3505 is available in MSOP-10. It operates from 6V to 30V over the temperature range of -40°C to +85°C. 6V to 30V supply voltage High efficiency: 90% typical PWM dimming control Fast 1.0MHz switching frequency Internal high power 35V NMOS Internal soft start Adjustable LED Open Protection Over-temperature protection MSOP-10 package APPLICATIONS  TV monitor backlighting  PDA, handheld computer  GPS receiver TYPICAL APPLICATION CIRCUIT Figure 1 Typical Application Circuit (Constant Current to Drive White LEDs) Note: These components with * symbol are recommended to fix the value. Or it will decrease the performance of whole system.    Lumissil Microsystems – www.lumissil.com Rev. D, 07/15/2014 1 IS31LT3505 PIN CONFIGURATION Package Pin Configuration (Top View) MSOP-10 PGND 1 10 LX VP 2 9 VDD AGND 3 8 NC EN 4 7 FB AGND 5 6 OVP PIN DESCRIPTION No. Pin 1 PGND 2 VP Internal 5V regulator. A power supply for the internal NMOS gate driver and the internal control circuitry. 3,5 AGND Signal ground. All external components ground must be connected to this pin. 4 EN 6 OVP 7 FB Feedback voltage of output. 8 NC No connection. 9 VDD Supply voltage. 10 LX Thermal Pad Description Power ground. Enable control input. Do not let this pin floating. Over-voltage protection of output. The drain of the internal NMOS. Connect to ground. Lumissil Microsystems – www.lumissil.com Rev. D, 07/15/2014 2 IS31LT3505 ORDERING INFORMATION INDUSTRIAL RANGE: -40°C TO +85°C Order Part No. Package QTY/Reel IS31LT3505-SLS2-TR MSOP-10, Lead-free 2500 Copyright  ©  2014  Lumissil  Microsystems.  All  rights  reserved.  Lumissil Microsystems reserves  the  right  to  make  changes  to  this  specification  and  its  products  at  any  time  without  notice.  Lumissil  Microsystems  assumes  no  liability  arising  out  of  the  application  or  use  of  any  information,  products  or  services described herein. Customers are advised to obtain the latest version of this device specification before relying on any published information and  before placing orders for products.  Lumissil Microsystems does not recommend the use of any of its products in life support applications where the failure or malfunction of the product can  reasonably be expected to cause failure of the life support system or to significantly affect its safety or effectiveness. Products are not authorized for use in  such applications unless Lumissil Microsystems receives written assurance to its satisfaction, that:  a.) the risk of injury or damage has been minimized;  b.) the user assume all such risks; and  c.) potential liability of Lumissil Microsystems is adequately protected under the circumstances Lumissil Microsystems – www.lumissil.com Rev. D, 07/15/2014 3 IS31LT3505 ABSOLUTE MAXIMUM RATINGS Supply voltage, VDD Voltage at EN, LX pin All other pins Operate temperature range Storage temperature range Junction temperature range JA ESD (HBM) -0.3V ~ +40V -0.3V ~ +40V -0.3V ~ +6.0V -40°C ~ +85°C -65°C ~ +150°C -40°C ~ +150°C 60°C/W ±2.5kV Note: Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other condition beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS TA = 25°C, VDD = 12V, unless otherwise noted. Symbol VDD Parameter Condition Supply voltage UVLO Undervoltage threshold ∆UVLO Undervoltage threshold hysteresis IDD Supply current ISD Min. Typ. 6 VP falling Continuous switching Max. Unit 30 V 2.9 V 100 mV 2 No switching 1.1 Shutdown current VEN = 0V 15 VP Internal regulator 6V