RT9261/A VFM Step-Up DC/DC Converter General Description Features zz z zz Minimal Number of External Components ( Only The RT9261 Series are VFM Step-up DC/DC ICs with ultra an Inductor, a Diode, and a Capacitor) low supply current by CMOS process and suitable for zz z zz Ultra Low Input Current ( 5A at Switch Off) use with battery-powered instruments. zz z zz 2% High Output Voltage Accuracy The RT9261 IC consists of an oscillator, a VFM control zz z zz Low Ripple and Low Noise circuit, a driver transistor (LX switch), a reference voltage zz z zz Low Start-up Voltage, 0.85V at 1mA unit, an error amplifier, resistors for voltage detection, and zz z zz 75% Efficiency with Low Cost Inductor a LX switch protection circuit. A low ripple and high zz z zz +50 ppm/ C Low Temperature-Drift efficiency step-up DC/DC converter can be constructed of zz z zz SOT-89 and SOT-23-5 Small Packages this RT9261 IC with only three external components. zz z zz RoHS Compliant and 100% Lead (Pb)-Free The RT9261A IC provides with a drive pin (EXT) for an external transistor, so that a power transistor can be Applications externally applied. Therefore, the RT9261A IC is z Power source for battery-powered equipment recommended for applications where large currents are z Power source for cameras, camcorders, VCRs, PDAs, required. EN pin enables circuit to set the standby supply pagers, electronic data banks, and hand-held current at a maximum of 0.5A. communication equipment z Power source for applications, which require higher Ordering Information voltage than that of batteries used in the appliances RT9261/A- Package Type Pin Configurations B : SOT-23-5 X : SOT-89 (TOP VIEW) Lead Plating System P : Pb Free G : Green (Halogen Free and Pb Free) Output Voltage 12 3 12 3 15 : 1.5V 16 : 1.6V : GND VOUT LX GND VOUT EXT 49 : 4.9V (TAB) (TAB) 50 : 5.0V RT9261 RT9261A Use external switch SOT-89 Use internal switch Note : Richtek products are : LX GND EXT GND RoHS compliant and compatible with the current require- 5 4 5 4 ments of IPC/JEDEC J-STD-020. Suitable for use in SnPb or Pb-free soldering processes. 23 23 EN VOUT NC EN VOUT NC Marking Information RT9261 RT9261A For marking information, contact our sales representative SOT-23-5 directly or through a Richtek distributor located in your area. DS9261/A-16 April 2011 www.richtek.com 1+ + + + + RT9261/A Typical Application Circuit D1 L1 D1 27H 1N5819 1N5819 Cb L1 RT9261xX RT9261AxX 0.01F LX VOUT V OUT V EXT VOUT V 100H IN OUT C OUT GND ZTX C OUT GND V IN 22F 650 Rb 22F Tr 300 Figure 1 Figure 2 L1 D1 D1 27H 1N5819 1N5819 L1 RT9261xB RT9261AxB NC LX VOUT V V OUT VOUT IN V OUT Cb 100H C OUT 0.01F NC C OUT V IN EXT 22F 22F EN ZTX GND EN GND 650 Rb Tr 300 Figure 3 Figure 4 D1 1N5819 L1 RT9261xB V LX VOUT OUT 27H C OUT NC V IN 22F EN Chip GND Enable Figure 5 www.richtek.com DS9261/A-16 April 2011 2