HT77XX PFM Step-up DC/DC Converter
Features
· Low start-up voltage: 0.7V (Typ.), 0.9V (Max.) · High efficiency: 85% (Typ...
HT77XX PFM Step-up DC/DC Converter
Features
· Low start-up voltage: 0.7V (Typ.), 0.9V (Max.) · High efficiency: 85% (Typ.), VOUT³2.7V · High output voltage accuracy: ±2.5% · Output voltage: 1.8V, 2.7V, 3.0V, 3.3V, 3.7V, 5.0V · Ultra low supply current IDD2: 4mA (Typ.) · Low ripple and low noise · Low shutdown current: 0.5mA (Typ.) · TO-92, SOT-89, SOT-23 and SOT-25 package
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Applications
· Palmtops/PDAs · Portable communicators/Smartphones · Cameras/Camcorders · Battery-powered equipment
General Description
The HT77XX 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 1.8V, 2.7V, 3.0V, 3.3V, 3.7V 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 HT77XX 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. HT7718 HT7727 HT7730 HT7733 HT7737 HT7750 Note: ²XX² stands for...