RT9261B VFM Step-Up DC/DC Converter General Description Features zz z zz Minimal Number of External Components (Only an The RT9261B Series are VFM Step-up DC/DC converter Inductor, a Diode, and a Capacitor) ICs with ultra low supply current by CMOS process and zz z zz Ultra Low Input Current (6.5A at Switch Off) suitable for use with battery-powered instruments. z Capable of Supplying 50mA Output Current with The RT9261B IC consists of an oscillator, a VFM control Internal Switch circuit, a driver transistor (LX switch), a reference voltage zz z zz 2% Output Voltage Accuracy unit, an error amplifier, resistors for voltage detection, and zz z zz Low Ripple and Low Noise a LX switch protection circuit. A low ripple and high efficiency zz z zz Low Start-up Voltage, 0.8V at 1mA step-up DC/DC converter can be constructed with the zz z zz 80% Efficiency with Low Cost Inductor RT9261B IC and only three external components. zz z zz +50 ppm/C Low Temperature-Drift The EN pin enables the circuit to set the standby supply z SOT-89 and SOT-23-5 Small Packages current at a maximum of 0.5A. zz z zz RoHS Compliant and 100% Lead (Pb)-Free Ordering Information Applications RT9261B- z Power source for battery-powered equipment Package Type z Power source for cameras, camcorders, VCRs, PDAs, B : SOT-23-5 pagers, electronic data banks, and hand-held X : SOT-89 communication equipment Lead Plating System P : Pb Free z Power source for appliances, which require higher G : Green (Halogen Free and Pb Free) voltage than that of batteries used in the appliances Output Voltage 15 : 1.5V Pin Configurations 16 : 1.6V : (TOP VIEW) 49 : 4.9V LX GND 50 : 5.0V Note : 5 4 Richtek products are : 23 RoHS compliant and compatible with the current require- ments of IPC/JEDEC J-STD-020. EN VOUT NC Suitable for use in SnPb or Pb-free soldering processes. SOT-23-5 Marking Information For marking information, contact our sales representative 12 3 directly or through a Richtek distributor located in your area. VOUT GND LX (TAB) SOT-89 DS9261B-16 April 2011 www.richtek.com 1+ + RT9261B Typical Application Circuit D1 1N5819 L1 RT9261B V LX VOUT OUT C OUT GND V IN 22F D1 1N5819 L1 RT9261B LX VOUT V OUT C OUT V IN EN GND 22F * L1 ranges from 27H to 120H Functional Pin Description Pin No. Pin Name Pin Function SOT-23-5 SOT-89 1 -- EN Chip Enable (Active High). 2 2 VOUT Output Voltage. 3 -- NC No Internal Connection. 4 1 GND Ground. 5 3 LX Pin for Switching. Function Block Diagram V Limiter LX LX V REF LXSW Buffer VOUT GND - OSC 190kHz + Error Amplifier Chip Enable EN www.richtek.com DS9261B-16 April 2011 2