RT8078AGQW Richtek

RT8078A 4A, 1MHz, Synchronous Step-Down Converter General Description Features zz z zz High Efficiency : Up to 95% The RT8078A is a high efficiency synchronous, step-down zz z zz Fixed Frequency : 1MHz DC/DC converter. It s input voltage range from 2.7V to 5.5V zz z zz No Schottky Diode Required that provides an adjustable regulated output voltage from zz z zz Internal Compensation 0.6V to V while delivering up to 4A of output current. IN zz z zz 0.6V Reference Allows Low Output Voltage The internal synchronous low on-resistance power zz z zz PWM 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 OCP, UVP, OVP, OTP fixed internally at 1MHz. The 100% duty cycle provides zz z zz RoHS Compliant and Halogen Free low dropout operation, hence extending battery life in portable systems. Current mode operation with internal compensation allows the transient response to be Applications optimized over a wide range of loads and output capacitors. z Portable Instruments The RT8078A is operated in PWM mode to achieve high z Battery Powered Equipment efficiency for a wide load range. The RT8078A is available z Notebook Computers in WDFN-10L 3x3 and SOP-8 (Exposed Pad) packages. z Distributed Power Systems z IP Phones z Digital Cameras Ordering Information RT8078A Package Type Pin Configurations QW : WDFN-10L 3x3 (W-Type) (TOP VIEW) SP : SOP-8 (Exposed Pad-Option 2) LX 1 10 PVIN Lead Plating System 9 LX 2 PVIN G : Green (Halogen Free and Pb Free) 3 8 SVIN LX PGOOD 4 7 NC Z : ECO (Ecological Element with 11 EN 5 6 FB Halogen Free and Pb free) Note : WDFN-10L 3x3 Richtek products are : RoHS compliant and compatible with the current require- LX 8 PVIN 2 LX 7 PVIN ments of IPC/JEDEC J-STD-020. GND 3 6 PGOOD SVIN Suitable for use in SnPb or Pb-free soldering processes. 9 4 EN 5 FB SOP-8 (Exposed Pad) DS8078A-01 June 2011 www.richtek.com 1 GNDRT8078A Marking Information RT8078AGQW RT8078AGSP 42= : Product Code RT8078AGSP : Product Number RT8078A YMDNN : Date Code YMDNN : Date Code 42=YM GSPYMDNN DNN RT8078AZQW RT8078AZSP RT8078AZSP : Product Number 42 : Product Code RT8078A YMDNN : Date Code 42 YM YMDNN : Date Code ZSPYMDNN DNN Typical Application Circuit RT8078A L OUT PGOOD LX V PGOOD OUT C R1 OUT R1 C PVIN FF V IN C IN FB SVIN C1 R2 Chip Enable GND EN Table 1. Recommended Component Selection V (V) R1 (k) R2 (k) C(pF) L ( H) C (F) OUT FF OUT 3.3 229.5 51 22 2 22 x 2 2.5 161.5 51 22 2 22 x 2 1.8 102 51 22 1.5 22 x 2 1.5 76.5 51 22 1.5 22 x 2 1.2 51 51 22 1.5 22 x 2 1.0 34 51 22 1.5 22 x 2 www.richtek.com DS8078A-01 June 2011 2