NCP1550

NCP1550 600 kHz PWM/PFM Step−Down DC−DC Controller The NCP1550 is a monolithic micropower high frequency voltage mode step−down controller IC, specially designed for battery operated hand−held electronic products. With appropriate external P−type MOSFET, the device can provide up to 2.0 A loading current with high conversion efficiency. The device operates in Constant−Frequency PWM mode at normal operation, that ensures low output ripple noise, and which will automatically switch to PFM mode at low output loads for higher efficiency. Additionally, value−added features of Chip Enable to reduce IC Off−State current and integrated feedback resistor network, make it the best choice for portable applications. The device is designed to operate for voltage regulation with minimum external components and board space. This device is available in a TSOP−5 package with six standard output voltage options. Features High Efficiency 92%, Typical Low Quiescent Bias Current of 50 mA (Typical at PFM Mode with No Load) Output Voltage Options from 1.8 V to 3.3 V with High Accuracy $2.0% Low Output Voltage Ripple, 50 mV, Typical PWM Switching Frequency at 600 kHz Automatic PWM/PFM Switchover at Light Load Condition Very Low Dropout Operation, 100% Max. Duty Cycle Chip Enable Pin with On−Chip 150 nA Pullup Current Source Low Shutdown Current, 0.3 mA, Typical Input Voltage Range from 2.45 V to 5.5 V Built−in Soft−Start Internal Undervoltage Lockout (UVLO) Protection Low ...