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
Rev
1.30
1
September
24,
2008
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
:
5
m
A
(Typ.)
·
Low
ripple
and
low
noise
·
Low
shutdown
current:
0.5
m
A
(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
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
TO92,
SOT89,
SOT23
and
SOT23-5
packages.
For
SOT23-5
package,
it
also
build-in
a
chip
enable
function