RT8024-18GB

RT8024 1.5MHz, 400mA, High Efficiency PWM Step-Down DC/DC Converter General Description Features zz z zz 2.5V to 5.5V Input Range The RT8024 is a high-efficiency pulse-width-modulated zz z zz Adjustable Output From 0.6V to V IN (PWM) step-down DC/DC converter. Capable of delivering zz z zz 1.0V, 1.2V, 1.5V, 1.8V, 2.5V and 3.3V Fixed/ 400mA output current over a wide input voltage range from Adjustable Output Voltage 2.5V to 5.5V, the RT8024 is ideally suited for portable zz z zz 400mA Output Current, 1A Peak Current electronic devices that are powered from 1-cell Li-ion zz z zz 95% Efficiency battery or from other power sources within the range such zz z zz No Schottky Diode Required as cellular phones, PDAs and handy-terminals. zz z zz 1.5MHz Fixed Frequency PWM Operation Internal synchronous rectifier with low R dramatically DS(ON) zz z zz Small SOT-23-5 and TSOT-23-5 Package reduces conduction loss at PWM mode. No external zz z zz RoHS Compliant and Halogen Free Schottky diode is required in practical application. The RT8024 automatically turns off the synchronous rectifier Applications while the inductor current is low and enters discontinuous z Cellular Telephones PWM mode. This can increase efficiency at light load z Personal Information Appliances condition. z Wireless and DSL Modems The RT8024 enters Low-Dropout mode when normal PWM z MP3 Players cannot provide regulated output voltage by continuously z Portable Instruments turning on the upper P-MOSFET. RT8024 enter shutdown mode and consumes less than 0.1A when EN pin is pulled Ordering Information low. RT8024(- ) Package Type The switching ripple is easily smoothed-out by small B : SOT-23-5 package filtering elements due to a fixed operation J5 : TSOT-23-5 frequency of 1.5MHz. This along with small SOT-23-5 and Lead Plating System TSOT-23-5 package provides small PCB area application. G : Green (Halogen Free and Pb Free) Other features include soft start, lower internal reference Output Voltage voltage with 2% accuracy, over temperature protection, Default : Adjustable 10 : 1.0V and over current protection. 12 : 1.2V 15 : 1.5V Pin Configurations 18 : 1.8V (TOP VIEW) 25 : 2.5V 33 : 3.3V FB/VOUT VIN Note : 5 4 Richtek products are : RoHS compliant and compatible with the current require- 23 ments of IPC/JEDEC J-STD-020. EN GND LX Suitable for use in SnPb or Pb-free soldering processes. SOT-23-5/TSOT-23-5 Marking Information For marking information, contact our sales representative directly or through a Richtek distributor located in your area. DS8024-02 March 2011 www.richtek.com 1RT8024 Typical Application Circuit L 2.2H 4 3 V V IN OUT VIN LX 2.2V to 5.5V C IN RT8024 4.7F C OUT 1 5 10F EN VOUT GND 2 Figure 1. Fixed Voltage Regulator L 2.2H 4 V 3 IN V VIN OUT LX 2.2V to 5.5V C IN C1 RT8024 4.7F R1 C OUT 1 5 EN FB 10F GND I R2 R2 2 R1 VOUT = VREF x 1+ R2 with R2 = 300k to 60k so the I = 2A to 10A, R2 -6 -6 and (R1 x C1) should be in the range between 3x10 and 6x10 for component selection. Figure 2. Adjustable Voltage Regulator Layout Guide GND GND V V V V IN IN OUT OUT C C C C IN IN OUT OUT L L 4 3 LX 4 3 LX VIN VIN 2 2 GND GND C1 5 1 EN FB 5 1 EN VOUT R1 R2 V GND OUT GND Figure 3 Layout note: 1. The distance that CIN connects to VIN is as close as possible (Under 2mm). 2. COUT should be placed near RT8024. www.richtek.com DS8024-02 March 2011 2