RT8015A 3A, 2MHz, Synchronous Step-Down Converter General Description Features zz z zz High Efficiency : Up to 95% The RT8015A is a high efficiency synchronous, step-down zz z zz Low R Internal Switches : 110m DS(ON) DC/DC converter. Its input voltage range is from 2.6V to zz z zz Programmable Frequency : 300kHz to 2MHz 5.5V and provides an adjustable regulated output voltage zz z zz No Schottky Diode Required from 0.8V to 5V while delivering up to 3A of output current. zz z zz 0.8V Reference Allows for Low Output Voltage The internal synchronous low on-resistance power zz z zz Forced Continuous Mode Operation switches increase efficiency and eliminate the need for zz z zz Low Dropout Operation : 100% Duty Cycle an external Schottky diode. The switching frequency is zz z zz RoHS Compliant and 100% Lead (Pb)-Free set by an external resistor or can be synchronized to an external clock. The 100% duty cycle provides low dropout Applications operation extending battery life in portable systems. z Portable Instruments Current mode operation with external compensation z Battery-Powered Equipment allows the transient response to be optimized over a wide z Notebook Computers range of loads and output capacitors. z Distributed Power Systems The RT8015A is operated in forced continuous PWM Mode z IP Phones which minimizes ripple voltage and reduces the noise and z Digital Cameras RF interference. The 100% duty cycle in Low Dropout Operation further Pin Configurations maximize battery life. (TOP VIEW) The RT8015A is available in the WDFN-10L 3x3 package. SHDN/RT 1 10 COMP 2 9 FB GND 3 8 LX VDD 4 7 PVDD LX Ordering Information 11 PGND 5 PVDD RT8015A WDFN-10L 3x3 Package Type QW : WDFN-10L 3x3 Marking Information Lead Plating System P : Pb Free For marking information, contact our sales representative G : Green (Halogen Free and Pb Free) directly or through a Richtek distributor located in your Note : area. Richtek products are : RoHS compliant and compatible with the current require- ments of IPC/JEDEC J-STD-020. Suitable for use in SnPb or Pb-free soldering processes. DS8015A-04 March 2011 www.richtek.com 1 9RT8015A Typical Application Circuit V IN 5V C COMP R COMP R RT8015A OSC 1000pF 30k 332k 10 1 SHDN/RT COMP 2 R2 240k GND 9 FB 3, 4 8 LX VDD 5 6, 7 PGND PVDD C R1 1 C IN 510k 22pF 22F L1 2H V OUT 2.5V/3A C OUT 22Fx2 Note : Using all Ceramic Capacitors Functional Pin Description Pin No. Pin Name Pin Function Oscillator Resistor Input. Connecting a resistor to ground from this pin sets the 1 SHDN/RT switching frequency. Forcing this pin to V causes the device to be shut down. DD Signal Ground. All small-signal components and compensation components should 2 GND connect to this ground, which in turn connects to PGND at one point. 3, 4 LX Internal Power MOSFET Switches Output. Connect this pin to the inductor. 5 PGND Power Ground. Connect this pin close to the negative terminal of C and C . IN OUT 6, 7 PVDD Power Input Supply. Decouple this pin to PGND with a capacitor. Signal Input Supply. Decouple this pin to GND with a capacitor. Normally V is DD 8 VDD equal to PVDD. Feedback Pin. This pin Receives the feedback voltage from a resistive divider 9 FB connected across the output. Error Amplifier Compensation Point. The current comparator threshold increases 10 COMP with this control voltage. Connect external compensation elements to this pin to stabilize the control loop. No Internal Connection. The exposed pad must be soldered to a large PCB and 11 (Exposed Pad) NC connected to GND for maximum power dissipation. www.richtek.com DS8015A-04 March 2011 2