LT1578 Datasheet | Linear Technology

LT1578/LT1578-2.5 1.5A, 200k Hz Step-Down Switching Regulator Features s s s s s s s s s s s s DESCRIPTIO 1.5A Switch Current High Efficiency- Low Loss 0.2Ω Switch Constant 200k Hz Switching Frequency 4V to 15V Input Voltage Range Minimum Output: 1.21V Low Supply Current: 1.9m A Low Shutdown Current: 20µA Easily Synchronizable Up to 400k Hz Cycle-by-Cycle Current Limit Reduced EMI Generation Low Thermal Resistance SO-8 Package Uses Small Low Value Inductors The LT ®1578 is a 200k Hz monolithic buck mode switching regulator. A 1.5A switch is included on the die along with all the necessary oscillator, control and logic circuitry. The topology is current mode for fast transient response and good loop stability. The LT1578 is a modified version of the LT1507 that has been optimized for noise sensitive applications. It will operate over a 4V to 15V input range. In addition, the reference voltage has been lowered to allow the device to produce output voltages down to 1.2V. Quiescent current has been reduced by a factor of two. Switch on resistance has been reduced by 30%. Switch transition times have been slowed to reduce EMI generation. The oscillator frequency has been reduced to 200k Hz to maintain high efficiency over a wide output current range. The pinout has been changed to improve PC layout by allowing the high current, high frequency switching circuitry to be easily isolated from low current, noise sensitive control circuitry. The new SO-8 package includes a fused ground lead that significantly reduces the thermal resistance of the device to extend the ambient operating temperature range. Standard surface mount external parts can be used including the inductor and capacitors. , LTC and LT are registered trademarks of Linear Technology Corporation. U APPLICATIO S s s s s Portable puters Battery-Powered Systems Battery Chargers Distributed Power Systems TYPICAL APPLICATION Efficiency vs Load Current 3.3V Buck Converter INPUT 5V TO 15V C3- 10µF TO 50µF 90...