RT8074GSP Richtek

RT8074 4A, 2MHz, Synchronous Step-Down Converter General Description Features zz z zz High Efficiency : Up to 95% The RT8074 is a high efficiency synchronous, step-down z Adjustable Frequency : 200kHz to 2MHz DC/DC converter. Its input voltage range is from 2.7V to zz z zz No Schottky Diode Required 5.5V and provides an adjustable regulated output voltage zz z zz 0.8V Reference Allows Low Output Voltage from 0.8V to 5V while delivering up to 4A of output current. zz z zz Low Dropout Operation : 100% Duty Cycle The internal synchronous low on-resistance power zz z zz Enable Function switches increase efficiency and eliminate the need for zz z zz Internal Soft-Start an external Schottky diode. The default switching zz z zz RoHS Compliant and Halogen Free frequency is set at 2MHz, if the RT pin is left open. It can also be varied from 200kHz to 2MHz by adding an external Applications resistor. Current mode operation with external z LCD TV and Monitor compensation allows the transient response to be z Notebook Computers optimized over a wide range of loads and output capacitors. z Distributed Power Systems z IP Phones Ordering Information z Digital Cameras RT8074 Package Type Pin Configurations SP : SOP-8 (Exposed Pad-Option 2) Lead Plating System (TOP VIEW) G : Green (Halogen Free and Pb Free) COMP 8 FB Note : 2 7 GND RT Richtek products are : GND EN 3 6 LX 9 RoHS compliant and compatible with the current require- 4 5 VIN LX ments of IPC/JEDEC J-STD-020. SOP-8 (Exposed Pad) Suitable for use in SnPb or Pb-free soldering processes. Typical Application Circuit RT8074 L 5, 6 V OUT LX V IN 4 1.1V VIN 1.5H 2.7V to 5.5V R1 C IN 750 10F 8 C FB OUT 3 22F R COMP EN 1 COMP R2 C 10k COMP 2k R 560pF OSC 2, 7 GND RT 9 (Exposed Pad) Note : Using all Ceramic Capacitors Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS8074-07 November 2012 www.richtek.com 1RT8074 Marking Information RT8074GSP : Product Number RT8074 YMDNN : Date Code GSPYMDNN Functional Pin Description Pin No. Pin Name Pin Function Error Amplifier Compensation Point. The current comparator threshold increases 1 COMP with this control voltage. Connect external compensation elements to this pin to stabilize the control loop. 2, Ground. The exposed pad must be soldered to a large PCB and connected to GND GND 9 (Exposed Pad) for maximum power dissipation. Enable Control Input. Float or connect this pin to logic high for enable. Connect to 3 EN GND for disable. 4 VIN Power Input Supply. Decouple this pin to GND with a capacitor. 5, 6 LX Internal Power MOSFET Switches Output. Connect this pin to the inductor. Oscillator Resistor Input. Connecting a resistor from this pin to GND sets the 7 RT switching frequency. If this pin is floating, the frequency will be set at 2MHz internally. Feedback. Receives the feedback voltage from a resistive divider connected across 8 FB the output. Function Block Diagram RT VIN SD ISEN Slope OSC Com COMP 0.8V Output OC EA Limit Clamp FB Driver Int-SS LX Hiccup Control Logic 0.7V P-G NISEN GND N-MOS I EN Enable OTP 0.4V LIM UV Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS8074-07 November 2012 2