LD6919

LD6919 11/13/2009 500mA, Ultra-Low Noise, High PSRR CMOS LDO Regulator with Soft Start Function REV: 00a General Description The LD6919 is a micro power linear regulator with very low output voltage drop during load transient, featuring ultra-low noise, low-dropout and high ripple rejection ratio for optimal performance of battery-powered systems. This SS pin can suppress the noise and is built in with soft start function. Using Leadtrend’s own proprietary control scheme, the output voltage can be set by the value chosen for the RJ resistor on SS pin. As well, the LD6919 can be stable with an output capacitor of 1μF which reduces the board space and cost. The LD6919 is available in a space saving SOT25, SC70-6 and DFN-6L 1.6mm x 1.6mm package. +Patented Features z Wide Operating Input Voltage Range：2.5V to 5.5V z Very-Low Output Voltage Drop during Load Transient z Ultra-Low Noise for RF Application z Shutdown Current <1μA z High PSRR 70dB@1kHz z Stable with 1μF Output Capacitor z Thermal Shutdown and Current Limiting Protection z VOUT Discharge Function z Soft Start Operation z Fixed Output Voltage: 1.5V to 3.3V (step：0.1V) and 3.45V or adjustable through RJ resistor Applications z Battery-Powered Equipment z Hand-Held Instruments z Palmtops, Notebook Computers Typical Application Fig. 1 Typical Application Circuit for General Purpose Reference example RJ (Ω)(1%) VOUT RJ open 3.1V 2.2M 3.0V 680k 2.8V 510k 2.7V 300k 2.5V 100k 1.8V VOUT(w.RJ ) = RJ(kΩ) RJ...