IS31LT3505-SLS2-TR ISSI

IS31LT3505 1.0MHZ BOOST CONVERTER WITH 35V INTERNAL NMOS July 2014 GENERAL DESCRIPTION FEATURES The IS31LT3505 is a constant current step-up 6V to 30V supply voltage converter with internal NMOS. The step-up converter High efficiency: 90% typical topology allows series connection of the white LEDs PWM dimming control so the LED currents are identical for uniform Fast 1.0MHz switching frequency brightness as well as constant output voltage to drive Internal high power 35V NMOS other devices. The output current of each channel Internal soft start can be set by an external resistor and dimming the Adjustable LED Open Protection brightness of LEDs with the PWM signal or DC Over-temperature protection voltage. The IS31LT3505 operates with a switching MSOP-10 package frequency up to 1MHz. A low 0.3V feedback voltage minimizes power loss in the current setting resistor APPLICATIONS for better efficiency. With OVP circuit, the chip and the system can be safe even if the load is not TV monitor backlighting connected. PDA, handheld computer GPS receiver IS31LT3505 is available in MSOP-10. It operates from 6V to 30V over the temperature range of -40C to +85C. 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 1 Rev. D, 07/15/2014 IS31LT3505 PIN CONFIGURATION Package Pin Configuration (Top View) PGND 1 10 LX VP VDD 2 9 MSOP-10 AGND 3 8 NC EN 4 7 FB AGND 5 6 OVP PIN DESCRIPTION No. Pin Description 1 PGND Power ground. Internal 5V regulator. A power supply for the internal NMOS 2 VP gate driver and the internal control circuitry. Signal ground. All external components ground must be 3,5 AGND connected to this pin. 4 EN Enable control input. Do not let this pin floating. 6 OVP Over-voltage protection of output. 7 FB Feedback voltage of output. 8 NC No connection. 9 VDD Supply voltage. 10 LX The drain of the internal NMOS. Thermal Pad Connect to ground. Lumissil Microsystems www.lumissil.com 2 Rev. D, 07/15/2014