HT77XX

PFM Step-up DC/DC Converter

Selection Table

Part No.

Output Voltage

Package

Marking

HT7718

1.8V

TO-92

SOT-89

SOT-23

SOT-25

HT77XX (for TO-92)

HT77XX# (for SOT-89)

77XX# (for SOT-23)

77XX# (for SOT-25)

HT7727

2.7V

HT7730

3.0V

HT7733

3.3V

HT7737

3.7V

HT7750

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 1.60

1

September 12, 2007

Features

Applications

General Description

The HT77XX series is a set of PFM step-up DC/DC con-

verter with high efficiency and low ripple. The series fea-

tures extremely low start-up voltage and high output

voltage accuracy. They require only three external com-

ponents to provide a fixed output voltage of 1.8V, 2.7V,

3.0V, 3.3V, 3.7V or 5.0V. CMOS technology ensures ul-

tra low supply current and makes them ideal for bat-

tery-operated applications powered from one or more

cells.

The HT77XX consists of an oscillator, a PFM control cir-

cuit, 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.

V O U T

G N D

V r e f

P F M C o n t r o l

O S C 1 1 5 k H z

B u f f e r

L X

C h i p E n a b l e

C E