HT7727A

HT77XXA PFM Step-up DC/DC Converter Features · Low start-up voltage: 0.7V (Typ.) · High efficiency: 85% (Typ.) · High output voltage accuracy: ±2.5% · Output voltage: 2.7V, 3.0V, 3.3V, 5.0V · Ultra low supply current IDD: 5mA (Typ.) · Low ripple and low noise · Low shutdown current: 0.5mA (Typ.) · TO-92, SOT-89, SOT-23 and SOT-25 package Applications · Palmtops/PDAs · Portable communicators/Smartphones · Cameras/Camcorders · Battery-powered equipment General Description The HT77XXA series is a set of PFM step-up DC/DC converter with high efficiency and low ripple. The series features extremely low start-up voltage and high output voltage accuracy. They require only three external components to provide a fixed output voltage of 2.7V, 3.0V, 3.3V or 5.0V. CMOS technology ensures ultra low supply current and makes them ideal for battery-operated applications powered from one or more cells. The HT77XXA consists of an oscillator, a PFM control circuit, a driver transistor, a reference voltage unit, and a high speed comparator. They employ pulse frequency modulation (PFM) for minimum supply current and ripple at light output loading. These devices are available in space saving TO-92, SOT-89, SOT-23 and SOT-25 packages. For SOT-25 package, it also build-in a chip enable function to reduce power consumption during shutdown mode. Selection Table Part No. HT7727A HT7730A HT7733A HT7750A Output Voltage 2.7V 3.0V 3.3V 5.0V Package TO-92 SOT-89 SOT-23 SOT-25 Marking HT77XXA (for ...