LX1918CLD中文资料Step-Down Buck Regulators数据手册Microchip规格书

描述 Description

The Microsemi LX1918 is a step down buck regulator with a synchronous rectifier. All MOSFET switches and compensation components are built in. The synchronous rectification eliminates the need of an external Schottky diode and maximizes efficiency (>95%) for a high step-down ratio and a low output voltage. The input supply voltage range is from 2.7V to 5.5V with a maximum output current of 1.8A.The LX1918 is a current mode PWM with optional PFM under light loads. The LX1918 can switch with a 1MHz free running internal oscillator or be synchronized with an external oscillator ranging from 500KHz to 1.25MHz; the high frequency allows for small size and low cost external components. The LX1918 output voltage is programmable with two resistors and can be tightly regulated down to 0.6V.The LX1918 MODE feature can either maximize efficiency or reduce EMI depending on the needs of the application. High efficiency (MODE = GND) is obtained by allowing the LX1918 to enter a PFM mode with discontinuous inductor current. Low EMI (MODE=VCC) is obtained by only operating in PWM mode even at no load.  The LX1918 features include soft start, cycle-by-cycle switch current limit, hiccup short circuit current limiting and thermal shut down.  The LX1918 comes in small 8 pin MLP package (fully RoHS compliant).FEATURES:o Input range voltage 2.7 to 5.5Vo Maximum output current, 1.8Ao Internal or External Synchronizationo Output Voltage from VIN to 0.6Vo PFM or PWM mode under light loado EMI support with force PWM modeo Efficiency up to 95%o No external Schottky diodeo Thermal shutdowno Cycle by cycle switch current limito UVLOo Short circuit protectiono 8 pin MLPAPPLICATIONS:o Lower power embedded applicationso WLAN power systemo Portable design with single cell Lion or 3 cells NiMH/NiCdo Low power portable storage applicationFEATURES:F  ROHS, PB Free-->  ROHS