Preliminary
RT9261B
VFM Step-up DC/DC Converter
General Description
Features
The RT9261B Series are VFM Step-up DC/DC
converter ICs with ultra low supply current by CMOS
process and suitable for use with battery-powered
instruments.
z Minimal Number of External Components
(Only an Inductor, a Diode, and a Capacitor)
z Ultra Low Input Current (6.5µA at Switch Off)
z Capable of Supplying 50mA Output Current
with Internal Switch
The RT9261B 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 with the
RT9261B IC and only three external components.
z
2% Output Voltage Accuracy
z Low Ripple and Low Noise
z Low Start-up Voltage, 0.8V at 1mA
z 80% Efficiency with Low Cost Inductor
z +50 ppm/°C Low Temperature-Drift
z SOT-89 and SOT-25 Small Packages
Applications
The CE pin enables the circuit to set the standby
supply current at a maximum of 0.5µA.
z Power source for battery-powered equipment
z Power source for cameras, camcorders, VCRs,
PDAs, pagers, electronic data banks, and hand-
held communication equipment
Ordering Information
RT9261B-ꢀꢀ ꢀ ꢀ
Package type
B : SOT-25
z Power source for appliances, which require
higher voltage than that of batteries used in the
appliances
X : SOT-89
Operating temperature range
C: Commercial standard
Pin Configurations
Part Number
Pin Configurations
Output voltage
15 : 1.5V
16 : 1.6V
:
TOP VIEW
RT9261B-ꢀꢀCX
(Plastic SOT-89)
1. GND
2. VOUT (TAB)
3. LX
1
5
1
2
2
3
49 : 4.9V
50 : 5.0V
TOP VIEW
RT9261B-ꢀꢀCB
(Plastic SOT-25)
4
1. CE
2. VOUT
3. NC
4. GND
5. LX
3
DS9261B-03 September 2001
www.richtek-ic.com.tw
1
ETC [ ETC ]
