• Product introduction

LT1578IS8

1.5A, 200kHz step-down switching regulator

peculiarity

• 1.5A switch current
• High efficiency, low loss 0.2Ohms switch
• Constant 200kHz switching frequency
• 4V to 15V input VoltageRange
• Minimum output: 1.21V
• Low supply current: 1.9 mA
• Low shutdown current: 20μA
• Easily synchronised to 400kHz
• Cycle-by-cycle current limit
• Reduces EMI generation
• Low thermal resistance SO-8 package
• Use small low inductance values

description

® The LT 1578 is a 200kHz monolithic buck mode switching regulator. A 1.5A switch is dead together with all the necessary oscillators, controls, and logic circuitry. The topology enables a current mode with fast transient response and good loop stability. The LT1578 is a modified version that has been optimized for noise sensitive applications, and the LT1507 has been optimized. It will operate from an input range of 4V to 15V. In addition, this reference voltage has been reduced to allow the output voltage generated by the device to drop to 1.2V. Quiescent current has been reduced by two factors. Resistance switching has been reduced by 30%. The transition time of the switch has been slowed down to reduce EMI generation. The frequency of the oscillator has been reduced to 200kHz to maintain high efficiency over a wide output current range. The pins have been changed to allow for high current, high-frequency switching circuits that can be easily isolated from low-current, noise-sensitive control circuits to improve PC layout. The new SO-8 package, including a fused ground wire, greatly reduces the thermal resistance of the device and extends the operating ambient temperature range. Standard surface-mount external components, including inductors and capacitors, can be used.