HT7737 与 HK7737 兼容，并有三种封装，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 (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.)
*ow ripple and low noise
*ow shutdown current: 0.5 A (Typ.)
*O-92, SOT-89, SOT-23 and SOT-25 package

Applications
* Palmtops/PDAs
*Portable communicators/Smartphones

*Cameras/Camcorders
*Battery-powered equipment