Product Overview
Holtek HT77xxA PFM Step-up DC/DC Converter
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, 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 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 3-pin SOT89, 3-pin SOT23 and 5-pin SOT23 packages. For 5-pin SOT23 package, it also build-in a chip enable function to reduce power consumption during shutdown mode
Applications
Palmtops/PDAs
Portable communicators/Smartphones
Cameras/Camcorders
Battery-powered equipment
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
Output current up to 200mA
Ultra low supply current IDD: 5 A (Typ.)
Low ripple and low noise
Low shutdown current: 0.5 A (Typ.)
Package types: 3-pin SOT89, 3-pin SOT23 and 5-pin SOT23 package
