HT7727A_12 Datasheet, PDF (1/14 Pages) Holtek Semiconductor Inc – PFM Step-up DC/DC Converter

HT77xxA
PFM Step-up DC/DC Converter
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 I_DD: 5mA (Typ.)
· Low ripple and low noise
· Low shutdown current: 0.5mA (Typ.)
· TO92, SOT89, SOT23 and SOT23-5 package
Applications
· Palmtops/PDAs
· Portable communicators/Smartphones
· Cameras/Camcorders
· Battery-powered equipment
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, 3.7V or 5.0V. CMOS technology ensures ultra low
supply current and makes them ideal for bat-
tery-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 TO92, SOT89, SOT23 and SOT23-5
packages. For SOT23-5 package, it also build-in a chip
enable function to reduce power consumption during
shutdown mode.
Selection Table
Part No.
HT7727A
HT7730A
HT7737A
HT7733A
HT7750A
Output Voltage
2.7V
3.0V
3.7V
3.3V
5.0V
Note: ²XX² stands for output voltages.
Block Diagram
Package
TO92
SOT89
SOT23
SOT23-5
Marking
HT77xxA (for TO92)
HT77xxA (for SOT89)
7xxA (for SOT23)
7xxA (for SOT23-5)
LX
L X L im ite r O S C 2 0 0 k H z
B u ffe r
P F M C o n tro l
VO UT
V re f
GND
C h ip E n a b le
CE
Rev 1.40
1
December 3, 2012