ST1S32 4 A DC step-down switching regulator Datasheet production data Features 4 A DC output current 2.8 V to 5.5 V input voltage Output voltage adjustable from 0.8 V 1.5 MHz switching frequency VFDFPN 8 4x4x1.0 Internal soft-start and enable Integrated 60 m and 45 m Power MOSFETs All ceramic capacitor Description Power Good (POR) The ST1S32 is an internally compensated 1.5 Cycle-by-cycle current limiting MHz fixed-frequency PWM synchronous step- Current foldback short-circuit protection down regulator. The ST1S32 operates from 2.8 V to 5.5 V input, while it regulates an output voltage VFDFPN 8 4x4x1.0 package as low as 0.8 V and up to V . IN Applications The ST1S32 integrates a 60 m high-side switch and a 45 m synchronous rectifier, allowing very P/ASIC/DSP/FPGA core and I/O supplies high efficiency with very low output voltages. Point of Load for: STB, TV, DVD The peak current mode control with internal Optical storage, hard disk drives, printers, compensation delivers a very compact solution audio/graphic cards with a minimum component count. The ST1S32 is available in 4 mm x 4 mm, 8-lead VFDFPN package. Figure 1. Application circuit L VOUT VIN VINSW SW VINA Cin a R3 R1 ST1S32 EN VFB PG Cout Cin sw R2 GND AM12608V1 May 2012 Doc ID 023246 Rev 1 1/29 This is information on a product in full production. www.st.com 29Contents ST1S32 Contents 1 Pin settings 3 1.1 Pin connection 3 1.2 Pin description 3 2 Maximum ratings 4 2.1 Thermal data . 4 3 Electrical characteristics . 5 4 Functional description . 7 4.1 Soft-start . 8 4.2 Error amplifier and control loop stability . 8 4.3 Overcurrent protection . 13 4.4 Enable function . 14 4.5 Light load operation . 14 4.6 Hysteretic thermal shutdown 14 5 Application information . 15 5.1 Input capacitor selection 15 5.2 Inductor selection . 16 5.3 Output capacitor selection 17 5.4 Thermal dissipation . 18 5.5 Layout considerations 20 6 Demonstration board . 22 7 Typical characteristics 24 8 Package mechanical data 26 9 Order codes . 28 10 Revision history . 28 2/29 Doc ID 023246 Rev 1