New HT77XX Product Release -- Low Start-up Voltage DC/DC Converter Series

March 14, 2005

The HT77XX series of devices are a new range of high-efficiency step up DC/DC converter CMOS device from Holtek. The devices use PFM techniques for their output control, and have the benefits of extremely low operating current and low noise characteristics. By using an integrated low impedance power transistor, the HT77XX series of devices only need to be connected to an external inductor, capacitor and diode to implement a complete DC/DC converter circuit, which can obtain high-efficiency ratings of up to 85%, providing related applications with a low cost and minimal area DC/DC solution.

The series is supplied in five fixed output voltage types of 2.7V, 3V, 3.3V, 3.7V and 5V. Their major advantage is in their ability to operate with input voltages as low as 0.6V, which when added to their extremely low supply current of only 4uA (IDD2), provide a range of devices which can extend battery life greatly, making them suitable for widespread use in single or multi-cell Alkaline, Lithium Ion or Ni-MH battery powered portable applications.

Regarding packaging the devices are available in TO-92, SOT-89 and SOT-25 package types. The SOT-25 package type, with their additional chip enable pin, can control an internal power down function, which if the device is placed into this power down mode, enables the device to consume an even further reduced operating current of only 0.5uA.