HT7737 與 HK7737 兼容，并有三種封裝，TO-92, SOT-89, and SOT-23。
General Description
The HK77XX 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-operatedapplications powered from one or more cells.
The 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.
Features
*Low start-up voltage: 0.7V (T.)
*High efficiency: 85% (T.)
*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 (T.)
*ow ripple and low noise
*ow shutdown current: 0.5 A (T.)
*O-92, SOT-89, SOT-23 and SOT-25 package
Applications
* Palms/PDAs
*Portable communicators/Smartphones
*Cameras/Camcorders
*Battery-powered equipment
