LT3505 Datasheet | Linear Technology

.. LT3505 1.2A, Step-Down Switching Regulator in 3mm × 3mm DFN DESCRIPTION The LT®3505 is a current mode PWM step-down DC/DC converter with an internal 1.4A power switch. The wide operating input range of 3.6V to 36V (40V maximum) makes the LT3505 ideal for regulating power from a wide variety of sources, including unregulated wall transformers, 24V industrial supplies and automotive batteries. The oscillator can be programmed for high frequency operation allowing the use of tiny, low cost external ponents or it can be programmed for lower frequency operation to maximize efficiency. Cycle-by-cycle current limit provides protection against shorted outputs and soft-start eliminates input current surge during start-up. The low current (<2µA) shutdown mode provides output disconnect, enabling easy power management in battery-powered systems. , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Features ! ! ! ! ! ! ! ! ! ! Wide Input Range: 3.6V to 36V Operating, 40V Maximum Up to 1.2A Output Current Resistor-Programmable Fixed-Frequency Operation from 200k Hz to 3MHz Output Adjustable Down to 780m V Short-Circuit Robust Uses Tiny Capacitors and Inductors Soft-Start Low Shutdown Current: <2µA Low VCESAT Switch: 350m V at 1A Thermally Enhanced, Low Profile 3mm x 3mm DFN-8 and MSOP-8 Packages APPLICATIONS ! ! ! ! ! Automotive Battery Regulation Industrial Control Supplies Wall Transformer Regulation Distributed Supply Regulation Battery-Powered Equipment TYPICAL APPLICATION 750k Hz, 3.3V Step-Down Converter VIN 4.2V TO 36V ON OFF VIN SHDN LT3505 FB RT 75.0k 1µF GND VC 69.8k 68p F 11.3k 10µF BOOST SW 0.1µF 10µH 36.5k 22p F VOUT 3.3V 1.1A, VIN > 5V 1.2A, VIN > 8V EFFICIENCY (%) 90 85 80 75 70 65 60 VIN = 12V VOUT = 3.3V 55 f SW = 750k Hz L = 10 H 50 0.8 0 0.2 0.4 0.6 LOAD CURRENT (A) Efficiency 3505 TA01 3505fc .. (Note...