ST1S50 4 A monolithic synchronous step-down switching converter with high efficiency at light load Datasheet - production data Applications Point of load for: STB, TVs, gateway Solid state disk drive, Blu-ray, DVD VFDFPN10 P/ASIC/DSP/FPGA core and I/O supplies Features Description 4 A output current The ST1S50 device is a 500 kHz fixed frequency PWM synchronous step-down regulator. The 4.0 V to 18 V input voltage ST1S50 operates from 4.0 V to 18 V input, while it Output voltage adjustable from 0.8 V to 0.88 x regulates an output voltage as low as 0.8 V and V IN up to 0.88 x V . IN 500 kHz switching frequency The ST1S50 device integrates a 95 m high-side High efficiency at light load switch and a 69 m synchronous rectifier allowing very high efficiency with very low output Programmable soft-start and enable voltages. Integrated 95 m and 69 m power MOSFETs The peak current mode control with a special All ceramic capacitor PFM mode enables high efficiency at a light load. Power Good The ST1S50 device is available in a VFDFPN10 Cycle-by-cycle current limiting 3 x 3 x 1 mm - 10 leads package. Short-circuit protection VFDFPN10 3 x 3 x 1 mm - 10 L Figure 1. Application circuit R3 Cbst L VIN VOUT PG BST VINSW SW VINA Cinsw Cina R1 EN SS ST1S50 FB COMP Cout Rc Css R2 GNDA GNDP Cc March 2015 DocID025723 Rev 4 1/29 This is information on a product in full production. www.st.comContents ST1S50 Contents 1 Pin settings 4 1.1 Pin connection 4 1.2 Pin description 4 2 Maximum ratings 5 3 Thermal data . 5 4 Electrical characteristics . 6 5 Functional description . 8 5.1 Programmable soft-start and enable . 9 5.2 Error amplifier and control loop stability . 9 5.3 Overcurrent protection . 13 5.4 Power Good function 14 5.5 Hysteretic thermal shutdown 14 6 Application information . 15 6.1 Input capacitor selection 15 6.2 Inductor selection . 16 6.3 Output capacitor selection 17 6.4 Compensation network selection . 18 6.5 Soft-start capacitor selection 19 6.5.1 Reset time . 19 6.5.2 CSS value . 20 6.6 Thermal dissipation . 20 6.7 Layout consideration 21 6.8 Demonstration board 23 7 Typical characteristics 24 8 Package information 26 VFDFPN10 package information . 26 2/29 DocID025723 Rev 4