RT8056GQW Richtek

RT8056 Dual 1A 1.5MHz Synchronous Step-Down Converters General Description Features zz z zz 2.8V to 5.5V Input Voltage Range The RT8056 is a high efficiency synchronous dual step- zz z zz 1.5MHz Fixed Frequency PWM Operation down converter. Capable of delivering two independent 1A zz z zz 2 x 1A Output Current output current over a wide input voltage range from 2.8V zz z zz Up to 95% Efficiency to 5.5V. The RT8056 is ideally suited for portable zz z zz No Schottky Diode Required electronic devices that are powered from 1-cell Li-ion zz z zz 0.6V Reference Allows for Low Output Voltage battery or from other power sources such as cellular zz z zz Low Dropout Operation : 100% Duty Cycle phones, PDAs and hand-held devices. The RT8056 zz z zz Small 10-Lead WDFN Package provides two operation modes including PWM/Low- zz z zz RoHS Compliant and Halogen Free Dropout auto switch and shutdown modes. The internal synchronous rectifier with low R dramatically reduces DS(ON) Applications conduction loss at PWM mode. No external Schottky z Portable Instruments diode is required in practical applications. The RT8056 z Microprocessors and DSP Core Supplies enters Low-Dropout mode when normal PWM cannot z Cellular Phones provide regulated output voltage by continuously turning z Wireless and DSL Modems on the upper P-MOSFET. The RT8056 enters shut-down z PC Cards mode and consumes less than 0.1A when EN pin is z Set Top Box pulled low. The switching ripple is easily smoothed-out by small package filtering elements due to a fixed Pin Configurations operating frequency of 1.5MHz. (TOP VIEW) Ordering Information FB2 1 10 LX2 2 9 NC EN2 RT8056 3 8 VIN GND Package Type 4 7 EN1 NC QW : WDFN-10L 3x3 (W-Type) 11 5 6 LX1 FB1 Lead Plating System WDFN-10L 3x3 G : Green (Halogen Free and Pb Free) Note : 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. Marking Information JM= : Product Code JM=YM YMDNN : Date Code DNN DS8056-02 April 2011 www.richtek.com 1 GNDRT8056 Typical Application Circuit L1 2.2H 6 V LX1 OUT1 R1 V 3 IN V = 0.6V x 1+ OUT1 VIN C OUT1 R1 R2 2.8V to 5.5V 22F 5 C FB1 IN R3 10F V = 0.6V x 1+ OUT2 R2 RT8056 R4 L2 2.2H 10 LX2 V OUT2 7 C EN1 OUT2 R3 22F Chip Enable 1 9 FB2 EN2 R4 8, 11 (Exposed Pad) GND Function Pin Description Pin No. Pin Name Pin Function 1 FB2 Feedback Input of Channel 2. 2, 4 NC No Internal Connection. 3 VIN Power Supply Input of Channel 1 & Channel 2. 5 FB1 Feedback Input of Channel 1. 6 LX1 Switching Node of Channel 1. 7 EN1 Chip Enable of Channel 1 (Active High). 8, Ground. The Exposed Pad must be soldered to a large PCB and connected to GND GND 11 (Exposed Pad) for maximum power dissipation. 9 EN2 Chip Enable of Channel 2 (Active High). 10 LX2 Switching Node of Channel 2. Function Block Diagram EN1/EN2 VIN RS1 OSC & Current Shutdown Limit Control Detector Slope Compensation Current Sense Error Control Driver LX1/LX2 Amplifier Logic FB1/FB2 PWM Comparator RC COMP UVLO & RS2 Power Good GND Detector V REF www.richtek.com DS8056-02 April 2011 2