HT77XXA

PFM Step-up DC/DC Converter

Selection Table

Part No.

Output Voltage

Package

Marking

HT7727A

2.7V

TO-92

SOT-89

SOT-23

SOT-25

HT77XXA (for TO-92)

HT77XXA# (for SOT-89)

77XXA# (for SOT-23)

77XXA# (for SOT-25)

HT7730A

3.0V

HT7733A

3.3V

HT7750A

5.0V

Note:

²XX² stands for output voltages.

Only lead free devices are available.

²#² stands for lead free devices. For the TO-92 package, there will be a

²#² mark at the end of the date code.

Block Diagram

Rev 1.10

1

September 26, 2007

Features

Applications

General Description

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 com-

ponents to provide a fixed output voltage of 2.7V, 3.0V,

3.3V or 5.0V. CMOS technology ensures ultra low sup-

ply 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 rip-

ple 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.

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