RT8058AGQW Richtek

RT8058A 1.2MHz, 2A, High Efficiency PWM Step-Down DC/DC Converter General Description Features zz z zz 0.6V Reference Allows Low Output Voltage The RT8058A is a current mode PWM step-down converter. zz z zz Low Dropout Operation : 100% Duty Cycle The chip is ideal for fixed frequency and low ripple zz z zz 2A Load Current applications over full range of load conditions. Its input zz z zz <2A Shutdown Current voltage range is from 2.6V to 5.5V with a constant 1.2MHz zz z zz Up to 95% Efficiency switching frequency that allows it to adopt tiny, low cost zz z zz No Schottky Diode Required capacitors and inductors with 2mm or less in height making zz z zz 1.2MHz Constant Switching Frequency it ideal for single-cell Li-lon/polymer battery applications. zz z zz Low R Internal Switches DS(ON) The low on resistance internal MOSFET can achieve high zz z zz Internally Compensated efficiency without the need of external schottky diodes in zz z zz Internal Soft-Start wide operating ranges and the output voltage is adjustable zz z zz Over temperature Protection from 0.6V to 5V that can provide up to 2A load current. zz z zz Short Circuit Protection The RT8058A operates at 100% duty cycle for low dropout zz z zz Small 10-Lead WDFN Package operation that extends battery life in portable devices. zz z zz RoHS Compliant and Halogen Free The RT8058A is available in a WDFN-10L 3x3 package. Applications Ordering Information z Portable Instruments RT8058A z Microprocessors and DSP Core supplies Package Type QW : WDFN-10L 3x3 (W-Type) z Cellular Telephones Lead Plating System z Wireless and DSL Modems P : Pb Free z Digital Cameras G : Green (Halogen Free and Pb Free) z PC Cards Note : Richtek products are : Pin Configurations RoHS compliant and compatible with the current require- (TOP VIEW) ments of IPC/JEDEC J-STD-020. PGND 1 10 LX Suitable for use in SnPb or Pb-free soldering processes. 9 PGND 2 LX GND 8 FB 3 PVDD 4 7 GND VDD 11 5 Marking Information POK EN E9= : Product Code WDFN-10L 3x3 YMDNN : Data Code E9=YM DNN DS8058A-02 April 2011 www.richtek.com 1 9RT8058A Typical Application Circuit RT8058A L1 V IN 8 PVDD 3.3H 9, 10 2.6V to 5.5V V OUT LX 6 1.2V/2A EN R1 100k 7 C1 R3 C2 VDD 3 1F 100k 10F C3 C4 FB 5 22F 1F POK R2 GND PGND 100k PGOOD 4 1, 2, 11 (Exposed Pad) Functional Pin Description Pin No. Pin Name Pin Function 1, 2, Power Ground. Connect this pin close to the () terminal of C and C . Exposed IN OUT PGND 11 (Exposed Pad) pad should be soldered to PCB board and connected to GND. Feedback Input Pin. Receives the feedback voltage from a resistive divider 3 FB connected across the output. Signal Ground. Return the feedback resistive dividers to this ground, which in turn 4 GND connects to PGND at one point. Power Good Indicator. Open-drain logic output that is opened when the output 5 POK voltage exceeds 90% of the regulation point. Enable pin. A logical high level at this pin enables the converter, while a logical low 6 EN level causes the converter to shut down. Signal Input Supply. Decouple this pin to GND with a capacitor. Normally VDD is 7 VDD equal to PVDD. Power Input Supply of converter power stage. Decouple this pin to PGND with a 8 PVDD capacitor. Internal Power MOSFET Switches Output of converter. Connect this pin to the 9, 10 LX inductor. Function Block Diagram PVDD Current Sense Slope OSC Com 0.6V Output OC EA Limit Clamp FB Driver Int-SS LX 0.3V Control UV Logic PGND POR VREF OTP 0.533V GND POK VDD EN www.richtek.com DS8058A-02 April 2011 2