RT9261 Datasheet, PDF (1/14 Pages) Richtek Technology Corporation – VFM Step-up DC/DC Converter

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. CE pin enables circuit to set the
standby supply current at a maximum of 0.5µA.
Ordering Information
RT9261A-…… … …
Package type
B : SOT-25
X : SOT-89
Operating temperature range
C: Commercial standard
Output voltage
15 : 1.5V
16 : 1.6V
:
49 : 4.9V
50 : 5.0V
A : Use external switch
Use internal switch
Features
z Minimal Number of External Components ( Only
an inductor, a diode, and a capacitor)
z Ultra Low Input Current ( 5µA at Switch Off)
z ± 2% High Output Voltage Accuracy
z Low Ripple and Low Noise
z Low Start-up Voltage, 0.85V at 1mA
z 75% Efficiency with Low Cost Inductor
z +50 ppm/°C Low Temperature-Drift
z SOT-89 and SOT-25 Small Packages
Applications
z Power source for battery-powered equipment
z Power source for cameras, camcorders, VCRs,
PDAs, pagers, electronic data banks, and hand-
held communication equipment
z Power source for applications, which require
higher voltage than that of batteries used in the
appliances
Pin Configurations
Part Number
RT9261-……CX
(Plastic SOT-89)
Pin Configurations
TOP VIEW
1 23
1. GND
2. VOUT (TAB)
3. LX
RT9261A-……CX
(Plastic SOT-89)
123
TOP VIEW
1. GND
2. VOUT (TAB)
3. EXT
RT9261-……CB
(Plastic SOT-25)
RT9261A-……CB
(Plastic SOT-25)
5
4
123
5
4
123
TOP VIEW
1. CE
2. VOUT
3. NC
4. GND
5. LX
TOP VIEW
1. CE
2. VOUT
3. NC
4. GND
5. EXT
DS9261/A-03 January 2002
www.richtek-ic.com.tw
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