RT8074GSP

® RT8074 4A, 2MHz, Synchronous Step-Down Converter General Description Features The RT8074 is a high efficiency synchronous, step-down DC/DC converter. Its input voltage range is from 2.7V to 5.5V and provides an adjustable regulated output voltage from 0.8V to 5V while delivering up to 4A of output current. z High Efficiency : Up to 95% z Adjustable Frequency : 200kHz to 2MHz No Schottky Diode Required 0.8V Reference Allows Low Output Voltage Low Dropout Operation : 100% Duty Cycle Enable Function Internal Soft-Start RoHS Compliant and Halogen Free The internal synchronous low on-resistance power switches increase efficiency and eliminate the need for an external Schottky diode. The default switching 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 resistor. Current mode operation with external compensation allows the transient response to be optimized over a wide range of loads and output capacitors. z z z z z z Applications z z z z Ordering Information z LCD TV and Monitor Notebook Computers Distributed Power Systems IP Phones Digital Cameras RT8074 Package Type SP : SOP-8 (Exposed Pad-Option 2) Pin Configurations Lead Plating System G : Green (Halogen Free and Pb Free) (TOP VIEW) COMP Note : Richtek products are : ` RoHS compliant and compatible with the current require- 8 GND 2 EN 3 7 GND 6 9 4 5 VIN FB RT LX 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 VIN 2.7V to 5.5V 4 LX VIN CIN 10µF FB 3 EN COMP L 5, 6 1.5µH 8 1 7 RT COUT 22µF RCOMP 10k ROSC R1 750 GND 2, 9 (Exposed Pad) VOUT 1.1V CCOMP 560pF R2 2k Note : Using all Ceramic Capacitors Copyright © 2012 Richtek Technology Corporation. All rights reserved. DS8074-07 November 2012 is a registered trademark of Richtek Technology Corporation. www.richtek.com 1 RT8074 Marking Information RT8074GSP : Product Number RT8074 GSPYMDNN YMDNN : Date Code Functional Pin Description Pin No. Pin Name 1 Pin Function Error Amplifier Compensation Point. The current comparator threshold increases with this control voltage. Connect external compensation elements to this pin to stabilize the control loop. COMP 2, GND 9 (Exposed Pad) Ground. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. 3 EN Enable Control Input. Float or connect this pin to logic high for enable. Connect to 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. 7 RT Oscillator Resistor Input. Connecting a resistor from this pin to GND sets the switching frequency. If this pin is floating, the frequency will be set at 2MHz internally. 8 FB Feedback. Receives the feedback voltage from a resistive divider connected across the output. Function Block Diagram RT SD VIN ISEN OSC Slope Com COMP 0.8V FB EA Output Clamp OC Limit Driver Int-SS LX Hiccup Control Logic 0.7V EN Enable 0.4V P-G UV Copyright © 2012 Richtek Technology Corporation. All rights reserved. www.richtek.com 2 NISEN OTP GND N-MOS ILIM is a registered trademark of Richtek Technology Corporation. DS8074-07 November 2012 RT8074 Absolute Maximum Ratings z z z z z z z z z z (Note 1) Supply Input Voltage, VIN --------------------------------------------------------------------------------------- −0.3V to 6.5V LX Pin Switch Voltage -------------------------------------------------------------------------------------------- −0.3V to (VIN + 0.3V)