Preliminary
RT9261/A
VFM Step-Up DC/DC Converter
General Description
The RT9261 Series are VFM Step-up DC/DC ICs with ultra
low supply current by CMOS process and suitable for
use with battery-powered instruments.
The RT9261 IC consists of an oscillator, a VFM control
circuit, a driver transistor (LX switch), a reference voltage
unit, an error amplifier, resistors for voltage detection, and
a LX switch protection circuit. A low ripple and high
efficiency step-up DC/DC converter can be constructed of
this RT9261 IC with only three external components.
The RT9261A IC provides with a drive pin (EXT) for an
external transistor, so that a power transistor can be
externally applied. Therefore, the RT9261A IC is
recommended for applications where large currents are
required. EN pin enables circuit to set the standby supply
current at a maximum of 0.5μA.
Features
Minimal Number of External Components ( Only
an Inductor, a Diode, and a Capacitor)
Ultra Low Input Current ( 5μA at Switch Off)
μ
± 2% High Output Voltage Accuracy
Low Ripple and Low Noise
Low Start-up Voltage, 0.85V at 1mA
75% Efficiency with Low Cost Inductor
+50 ppm/
°
C Low Temperature-Drift
SOT-89 and
SOT-23-5
Small Packages
RoHS Compliant and 100% Lead (Pb)-Free
Applications
Power source for battery-powered equipment
Power source for cameras, camcorders, VCRs, PDAs,
pagers, electronic data banks, and hand-held
communication equipment
Power source for applications, which require higher
voltage than that of batteries used in the appliances
Ordering Information
RT9261/A-
Package Type
B : SOT-23-5
X : SOT-89
Marking Information
For marking information, contact our sales representative
Operating Temperature Range
directly or through a RichTek distributor located in your
P : Pb Free with Commercial Standard
G : Green (Halogen Free with Commer-
area, otherwise visit our website for detail.
cial Standard)
Output Voltage
15 : 1.5V
16 : 1.6V
:
49 : 4.9V
50 : 5.0V
Use external switch
Use internal switch
1
2
3
Pin Configurations
(TOP VIEW)
Note :
RichTek Pb-free and Green products are :
RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
Suitable for use in SnPb or Pb-free soldering processes.
100% matte tin (Sn) plating.
1
2
3
GND VOUT LX
(TAB)
GND VOUT EXT
(TAB)
RT9261-
CX
SOT-89
RT9261A-
CX
DS9261/A-12 March 2007
www.richtek.com
1
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
