HT77XXA
PFM Step-up DC/DC Converter
Features
· Low start-up voltage: 0.7V (Typ.)
· High efficiency: 85% (Typ.)
· Ultra low supply current IDD: 5mA (Typ.)
· Low ripple and low noise
· High output voltage accuracy: ±2.5%
· Low shutdown current: 0.5mA (Typ.)
· Output voltage: 2.7V, 3.0V, 3.3V, 5.0V
· TO92, SOT89, SOT23 and SOT23-5 package
· Output current up to 200mA
Applications
· Palmtops/PDAs
· Cameras/Camcorders
· Portable communicators/Smartphones
· Battery-powered equipment
General Description
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 ripple 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.
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 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-operated
applications powered from one or more cells.
Selection Table
Part No.
2.7V
HT7730A
3.0V
HT7733A
3.3V
HT7750A
Note:
Output Voltage
HT7727A
Package
Marking
TO92
SOT89
SOT23
SOT23-5
HT77XXA (for TO92)
HT77XXA# (for SOT89)
7XXA# (for SOT23)
7XXA# (for SOT23-5)
5.0V
²XX² stands for output voltages.
Only lead free devices are available. ²#² stands for lead free devices. For the TO92 package, there will be a ²#²
mark at the end of the date code.
Block Diagram
V re f
L X
L X L im ite r
V O U T
O S C 2 0 0 k H z
P F M
B u ffe r
C o n tro l
G N D
C h ip E n a b le
C E
Rev 1.30
1
September 24, 2008
